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Welcome to Our Generation USA!

Below, we cover
THE COSMOS 
from early astronomy to the first satellite launch, including manned space travel and moon landings, Mars and other destinations, as well as the space shuttles and the International Space Station, including Earth-bound Planetariums/Observatories and Space Telescopes.


Space Exploration including Moon Landings
YouTube Video: We Are the Explorers (NASA)
YouTube Video: John F. Kennedy* "Landing a man on the Moon" Address to Congress - May 25, 1961
YouTube Video of Neil Armstrong* - First Moon Landing 1969
* -- John F. Kennedy
**-- Neil Armstrong
Pictured:  LEFT: Saturn V rocket, used for the American manned lunar landing missions; RIGHT: The (unmanned) Mars Rover

Space exploration is the discovery and exploration of celestial structures in outer space by means of evolving and growing space technology. While the study of space is carried out mainly by astronomers with telescopes, the physical exploration of space is conducted both by unmanned robotic space probes and human spaceflight.

While the observation of objects in space, known as astronomy, predates reliable recorded history, it was the development of large and relatively efficient rockets during the mid-twentieth century that allowed physical space exploration to become a reality. Common rationales for exploring space include advancing scientific research, national prestige, uniting different nations, ensuring the future survival of humanity, and developing military and strategic advantages against other countries.

Space exploration has often been used as a proxy competition for geopolitical rivalries such as the Cold War. The early era of space exploration was driven by a "Space Race" between the Soviet Union and the United States.

The launch of the first human-made object to orbit Earth, the Soviet Union's Sputnik 1, on 4 October 1957, and the first Moon landing by the American Apollo 11 mission on 20 July 1969 are often taken as landmarks for this initial period.

The Soviet Space Program achieved many of the first milestones, including the first living being in orbit in 1957, the first human spaceflight (Yuri Gagarin aboard Vostok 1) in 1961, the first spacewalk (by Aleksei Leonov) on 18 March 1965, the first automatic landing on another celestial body in 1966, and the launch of the first space station (Salyut 1) in 1971.

After the first 20 years of exploration, focus shifted from one-off flights to renewable hardware, such as the Space Shuttle program, and from competition to cooperation as with the International Space Station (ISS).

With the substantial completion of the ISS following STS-133 in March 2011, plans for space exploration by the U.S. remain in flux. Constellation, a Bush Administration program for a return to the Moon by 2020 was judged inadequately funded and unrealistic by an expert review panel reporting in 2009.

The Obama Administration proposed a revision of Constellation in 2010 to focus on the development of the capability for crewed missions beyond low Earth orbit (LEO), envisioning extending the operation of the ISS beyond 2020, transferring the development of launch vehicles for human crews from NASA to the private sector, and developing technology to enable missions to beyond LEO, such as Earth–Moon L1, the Moon, Earth–Sun L2, near-Earth asteroids, and Phobos or Mars orbit.

In the 2000s, the People's Republic of China initiated a successful manned spaceflight program, while the European Union, Japan, and India have also planned future crewed space missions. China, Russia, Japan, and India have advocated crewed missions to the Moon during the 21st century, while the European Union has advocated manned missions to both the Moon and Mars during the 20th and 21st century.

From the 1990s onwards, private interests began promoting space tourism and then public space exploration of the Moon (see Google Lunar X Prize).

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​The Hubble Space Telescope
YouTube Video: Hubble Space Telescope Deploy (April 24, 1990)
YouTube Video: Images Taken From the Hubble Space Telescope
Pictured: The Hubble Space Telescope as seen from the departing Space Shuttle Atlantis, flying Servicing Mission 4 (STS-125), the sixth and final Hubble mission

​The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.

Although not the first space telescope, Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. The HST is named after the astronomer Edwin Hubble, and is one of NASA's Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope.

With a 2.4-meter (7.9 ft) mirror, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared spectra. Hubble's orbit outside the distortion of Earth's atmosphere allows it to take extremely high-resolution images, with substantially lower background light than ground-based telescopes.

Hubble has recorded some of the most detailed visible light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.

The HST was built by the United States space agency NASA, with contributions from the European Space Agency. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center controls the spacecraft.

Space telescopes were proposed as early as 1923. Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster (1986). When finally launched in 1990, Hubble's main mirror was found to have been ground incorrectly, compromising the telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.

Hubble is the only telescope designed to be serviced in space by astronauts. After launch by Space Shuttle Discovery in 1990, five subsequent Space Shuttle missions repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments.

The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003). However, after spirited public discussion, NASA administrator Mike Griffin approved the fifth servicing mission, completed in 2009. The telescope is operating as of 2017, and could last until 2030–2040. Its scientific successor, the James Webb Space Telescope (JWST), is scheduled for launch in 2019.

Click on any of the following blue hyperlinks for more about the Hubble Space Telescope:
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​Elon Musk and the Launch of SpaceX aboard the Falcon Heavy, the world's most powerful rocket​
YouTube Video: Elon Musk reveal SpaceX's most detailed plans to colonize Mars
​YouTube Video: SpaceX launches world's most powerful rocket (CNN 2-6-18)
Pictured below (L-R): Elon Musk and the SpaceX Launch on February 6, 2018

SpaceX launches Falcon Heavy, the world's most powerful rocket on February 6, 2018:
by CNN February 7, 2018:

SpaceX has done it again!

The pioneering rocket firm just pulled off the unexpected, and carried out what appears to be a seamless first-ever launch of its massive new rocket, called Falcon Heavy.

That makes SpaceX, the game-changing company helmed by billionaire Tesla CEO Elon Musk, the owner of the world's most powerful operational rocket.

Falcon Heavy took flight Tuesday around 3:45 pm ET from Kennedy Space Center in Florida.

"I'm still trying to absorb everything that happened because it's still kind of surreal to me," Musk told reporters after the launch.

​Thousands of onlookers in Florida could be heard cheering on the company's livestream, which was viewed by about 3 million people.

In the run up to launch, it wasn't at all clear that the rocket would work.

"People [came] from all around the world to see what will either be a great rocket launch or the best fireworks display they've ever seen," Musk said in an interview with CNN's Rachel Crane Monday.

Related: Falcon Heavy: How it stacks up with other massive rockets

The rocket's smooth takeoff wasn't the only stunning thing about this launch.

In a never-before-seen feat, SpaceX also managed to guide at least two of the Falcon Heavy's first-stage rocket boosters to land upright back on Earth. They cut back through the Earth's atmosphere and landed in unison at a Kennedy Space Center landing pad.

"That was probably the most exciting thing I've ever seen -- literally ever," Musk said.
The third booster was supposed to land on a sea-faring platform called a droneship -- but just as it was about to land, the livestream cut out. Musk confirmed after the launch that the booster crashed.

On board the rocket that's now headed deeper into space is Musk's personal Tesla (TSLA) roadster.

At the wheel is a dummy dressed in a spacesuit. Musk said in December the car would play David Bowie's "Space Oddity" on repeat. Cameras on board the car show it cruising by Earth, which appears as a big blue orb in the background. Musk plans to send the car into orbit around the sun.

He announced last year he planned to put his car on the inaugural Falcon Heavy flight. When asked on Twitter why he wanted to throw away a $100,000 vehicle, he replied, "I love the thought of a car drifting apparently endlessly through space and perhaps being discovered by an alien race millions of years in the future."

Related: Everything you need to know about SpaceX's Falcon Heavy

Tuesday's success marked a huge step forward for a company that's already managed to shake up the rocket industry with its groundbreaking technology.

The company made the world take notice when it proved it can safely return first-stage rocket boosters to Earth with its Falcon 9 rocket, which the company has used for more than 40 missions dating back to 2012.

​Those rockets have a single first-stage booster, and SpaceX has safely recaptured them after 21 Falcon 9 launches.

Now, SpaceX routinely puts used boosters back to work. In fact, the inaugural Falcon Heavy flight actually used two pre-flown Falcon 9 boosters (the center booster was new.)
Reusing hardware is part of SpaceX's plan to drive down the cost of launches.

Before SpaceX came along, companies just discarded rockets after each mission.

Note: the Falcon Heavy is not the most powerful rocket in history. That honor belongs to NASA's Saturn V rocket, which was used for the Apollo moon landings and was retired in the 1970s.







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​​History of Space Flight
YouTube Video of John Glenn's historic space flight (1962)
YouTube Video of Neil Armstrong - First Moon Landing 1969

Spaceflight became part of human achievement in the 20th century following theoretical and practical breakthroughs by Konstantin Tsiolkovsky and Robert H. Goddard.

The Soviet Union took the lead in the post-war Space Race, launching the first satellite, the first man and the first woman into orbit. The United States caught up with, and then passed, their Soviet rivals during the mid-1960s, landing the first man on the Moon in 1969. In the same period, France, the United Kingdom, Japan and China were concurrently developing more limited launch capabilities.

Following the end of the Space Race, spaceflight has been characterised by greater international co-operation, cheaper access to low Earth orbit and an expansion of commercial ventures.

Interplanetary probes have visited all of the planets in the Solar System, and humans have remained in orbit for long periods aboard space stations such as Mir and the ISS. Most recently, China has emerged as the third nation with the capability to launch independent manned missions, whilst operators in the commercial sector have developed re-usable booster systems and craft launched from airborne platforms.

Background:
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At the beginning of the 20th century, there was a burst of scientific investigation into interplanetary travel, inspired by fiction by writers such as Jules Verne (From the Earth to the Moon, Around the Moon) and H.G. Wells (The First Men in the Moon, The War of the Worlds).

The first realistic proposal of spaceflight goes back to Konstantin Tsiolkovsky. His most famous work, "Исследование мировых пространств реактивными приборами" (Issledovanie mirovikh prostranstv reaktivnimi priborami, or The Exploration of Cosmic Space by Means of Reaction Devices), was published in 1903, but this theoretical work was not widely influential outside Russia.

Spaceflight became an engineering possibility with the work of Robert H. Goddard's publication in 1919 of his paper "A Method of Reaching Extreme Altitudes", where his application of the de Laval nozzle to liquid fuel rockets gave sufficient power for interplanetary travel to become possible. This paper was highly influential on Hermann Oberth and Wernher Von Braun, later key players in spaceflight.

In 1929, the Slovene officer Hermann Noordung was the first to imagine a complete space station in his book The Problem of Space Travel.

​The first rocket to reach space was a German V-2 rocket, on a vertical test flight in June 1944. After the war ended, the research and development branch of the (British) Ordinance Office organised Operation Backfire which, in October 1945, assembled enough V-2 missiles and supporting components to enable the launch of three (possibly four, depending on source consulted) of them from a site near Cuxhaven in northern Germany.

Although these launches were inclined and the rockets didn't achieve the altitude necessary to be regarded as sub-orbital spaceflight, the Backfire report remains the most extensive technical documentation of the rocket, including all support procedures, tailored vehicles and fuel composition.

Subsequently, the British Interplanetary Society proposed an enlarged man-carrying version of the V-2 called Megaroc. The plan, written in 1946, envisaged a three-year development programme culminating in the launch of test pilot Eric Brown on a sub-orbital mission in 1949.

The decision by the Ministry of Supply under Attlee's government to concentrate on research into nuclear power generation and sub-sonic passenger jet aircraft over supersonic atmospheric flight and spaceflight delayed the introduction of both of the latter (although only by a year in the case of supersonic flight, as the data from the Miles M.52 was handed to Bell Aircraft.

Click on any of the following blue hyperlinks for more about The History of Space Flight:





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National Aeronautics and Space Administration (NASA) including a List of NASA Missions
YouTube Video of Neil Armstrong - First Moon Landing 1969

Click here for a List of NASA Missions.

The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research.

President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science.

The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA's predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most US space exploration efforts have been led by NASA, including the Apollo Moon landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles.

The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches.

NASA science is:
NASA shares data with various national and international organizations such as from the Greenhouse Gases Observing Satellite.

Click on any of the following blue hyperlinks for more about NASA:






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​Observatory including a List of Observatories around the Globe
YouTube Video: Professor Stephen Hawking explains how stars are made.
* -- Stephen Hawking
Pictured: The Hubble Telescope

Click here for a List of Observatories around the Globe.

​An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology
are  examples of disciplines for which observatories have been constructed.

Historically, observatories were as simple as containing an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena).

While other sciences, such as volcanology and meteorology, also use facilities called observatories for research and observations, this list is limited to observatories that are used to observe celestial objects.

Astronomical observatories are mainly divided into four categories:
  1. space based,
  2. airborne,
  3. ground based
  4. and underground based.

Many modern telescopes and observatories are located in space to observe astronomical objects in wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere (such as ultraviolet radiation, X-rays, and gamma rays) and are thus impossible to observe using ground-based telescopes.

Being above the atmosphere, these space observatories can also avoid the effects of atmospheric turbulence that plague ground based telescopes, although new generations of adaptive optics telescopes have since then dramatically improved the situation on the ground.

The space high vacuum environment also frees the detectors from the ancestral diurnal cycle due to the atmospheric blue light background of the sky, thereby increasing significantly the observation time.

An intermediate variant is the airborne observatory, specialized in the infrared wavelengths of the EM spectrum, that conduct observations above the part of the atmosphere containing water vapor that absorbs them, in the stratosphere.

Historically, astronomical observatories consisted generally in a building or group of buildings where observations of astronomical objects such as sunspots, planets, asteroids, comets, stars, nebulae, and galaxies in the visible wavelengths of the electromagnetic spectrum were conducted.

At first, for millennia, astronomical observations have been made with naked eyes. Then with the discovery of optics, with the help of different types of refractor telescopes and later with reflector telescopes.

Their use allowed to dramatically increase both the collecting power and limit of resolution, thus the brightness, level of detail and apparent angular size of distant celestial objects allowing them to be better studied and understood.

Following the development of modern physics, new ground based facilities have been constructed to conduct research in the radio and microwave wavelengths of the electromagnetic spectrum, with radio telescopes and dedicated microwave telescopes.

Modern astrophysics has extended the field of study of celestial bodies to non electromagnetic vectors, such as neutrinos, neutrons and cosmic-rays or gravitational waves. Thus new types of observatories have been developed. Interferometers are at the core of gravitational wave detectors.

In order to limit the natural or artificial background noise, most particle detector based observatories are built deep underground.

Click on any of the following blue hyperlinks for more about Observatories:







​Planetarium --  A Listing of Planetariums
YouTube Video: Seven Wonders planetarium show
Pictured: A front view of Griffith Observatory, sitting above Hollywood in Griffith Park, Los Angeles, California

Click here for a List of Planetariums worldwide.

A planetarium is a theater built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation.

A dominant feature of most planetariums is the large dome-shaped projection screen onto which scenes of stars, planets and other celestial objects can be made to appear and move realistically to simulate the complex 'motions of the heavens'.

The celestial scenes can be created using a wide variety of technologies, for example precision-engineered 'star balls' that combine optical and electro-mechanical technology, slide projector, video and full dome projector systems, and lasers.

Whatever technologies are used, the objective is normally to link them together to provide an accurate relative motion of the sky. Typical systems can be set to display the sky at any point in time, past or present, and often to show the night sky as it would appear from any point of latitude on Earth.

Planetariums range in size from the Hayden Planetarium's 21-meter dome seating 423 people, to three-meter inflatable portable domes where children sit on the floor. Such portable planetaria serve education programs outside of the permanent installations of museums and science centers.

The term planetarium is sometimes used generically to describe other devices which illustrate the solar system, such as a computer simulation or an orrery. Planetarium software refers to a software application that renders a three-dimensional image of the sky onto a two-dimensional computer screen. The term planetarian is used to describe a member of the professional staff of a planetarium.

Click on any of the following blue hyperlinks for more about Planetariums:







​Stephen Hawking (1942-2018)
YouTube Video featuring Stephen Hawking: Questioning the universe by TED
Pictured: Stephen Hawking with his Family

Stephen William Hawking, CH, CBE, FRS, FRSA (born 8 January 1942) is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge.

His scientific works include a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics. He is a vigorous supporter of the many-worlds interpretation of quantum mechanics.

Hawking is an Honorary Fellow of the Royal Society of Arts, a lifetime member of the Pontifical Academy of Sciences, and a recipient of the Presidential Medal of Freedom, the highest civilian award in the US.

He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009 and has achieved commercial success with works of popular science in which he discusses his own theories and cosmology in general; his book A Brief History of Time appeared on the British Sunday Times best-seller list for a record-breaking 237 weeks.

Hawking has a rare early-onset, slow-progressing form of amyotrophic lateral sclerosis (ALS) that has gradually paralysed him over the decades. He now communicates using a single cheek muscle attached to a speech-generating device.

Click on any of the following blue hyperlinks for more about Stephen Hawking:
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​Carl Sagan
YouTube Video: Humanity by Carl Sagan*
​* -- Carl Sagan gives the best speech ever about humanity and how foolish we behave. Pale Blue Dot is one of the most important and reflective speeches about the human condition and our place in the Universe. The Pale Blue Dot is a photograph of Earth taken in 1990 by the Voyager 1 space probe from a record distance of about 6 billion kilometers from Earth, as part of the solar system Family Portrait series of images.

Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer, cosmologist, astrophysicist, astrobiologist, author, science popularizer, and science communicator in astronomy and other natural sciences.

He is best known for his work as a science popularizer and communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.

Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.

Sagan published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books. He wrote many popular science books, such as The Dragons of Eden, Broca's Brain and Pale Blue Dot, and narrated and co-wrote the award-winning 1980 television series Cosmos: A Personal Voyage. The most widely watched series in the history of American public television, Cosmos has been seen by at least 500 million people across 60 different countries.

The book Cosmos was published to accompany the series. He also wrote the science fiction novel Contact, the basis for a 1997 film of the same name. His papers, containing 595,000 items, are archived at The Library of Congress.

Sagan always advocated scientific skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI). He spent most of his career as a professor of astronomy at Cornell University, where he directed the Laboratory for Planetary Studies.

Sagan and his works received numerous awards and honors, including the NASA Distinguished Public Service Medal, the National Academy of Sciences Public Welfare Medal, the Pulitzer Prize for General Non-Fiction for his book The Dragons of Eden, and, regarding Cosmos: A Personal Voyage, two Emmy Awards, the Peabody Award and the Hugo Award.

​He married three times and had five children. After suffering from myelodysplasia, Sagan died of pneumonia at the age of 62, on December 20, 1996.

For additional Background of Carl Sagan, click on any of the following blue hyperlinks:






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NASA'a Voyager Space Program: including a New York Times article about the Voyager: "A Reverie for the Voyager Probes, Humanity’s Calling Cards"
YouTube Video About Voyager Space Program: Voyager at 40: Keep Reaching for the Stars
Pictured below: Montage of planets and some moons the two Voyager spacecraft have visited and studied

A Reverie for the Voyager Probes
The New York Times By Dennis Overbye, Aug. 21, 2017 

"In the shadow, one might say, of the Great American Eclipse, a major anniversary in the history of space exploration — and indeed cosmic consciousness — is being celebrated.
It was 40 years ago, on Aug. 20 and Sept. 5, 1977, that a pair of robots named Voyager were dispatched to explore the outer solar system and the vast darkness beyond.

What resulted was nothing less than a re-imagining of what a world might be and what strange cribs of geology and chemistry might give rise to life in some form or other.
It was a real-life Star Trek adventure, but the crew stayed home, communicating with their two spacecraft through a billion-mile bucket brigade of data bits.

New computer programs went one way, and data — including scratchy photos of new landscapes and the whispering moans of interplanetary plasma fields — came back the other way. All of it was being carried out by a robot brain with the memory capacity of an old-fashioned digital watch.

The spacecraft had been designed to make what scientists called the Grand Tour, taking advantage of a once-every-175-year planetary alignment. Voyager 1 and Voyager 2 were to use the gravity of the outer planets to slingshot from Jupiter to Saturn, and to Uranus and Neptune, and then beyond the edge of the sun’s domain into interstellar space.

In the end, only half the tour — to Jupiter and Saturn — was actually approved. But the Voyager crew packed for a much longer journey. When they lifted off 40 years ago, the two spacecraft carried golden records inscribed with pictures and sounds from Earth, greetings from President Jimmy Carter and instructions on how to play it all.

The Voyagers would observe the universe, and give something back to whoever might one day find them.

The robot emissaries cruised the solar system through presidential administrations, wars and scandals, and the Challenger disaster, which happened as Voyager 2 was pulling away from Uranus.

At every planetfall, the crew members, a little older and a little grayer each time, reconvened at the Jet Propulsion Laboratory in Pasadena, Calif., for a weeklong marathon of discovery, a circus of science on the fly.

With imagery returned by probes, what had been fuzzy dots in the world’s biggest telescopes bloomed into worlds.

Back on Earth, some theoreticians claimed to be homing in on a putative theory of everything, an Einsteinian dream of an equation simple enough to be inscribed on a T-shirt.

But in space, scientists were finding that such theories were no help against nature’s endless capacity to invent and surprise. Each new world revealed by the Voyagers was a head-scratcher.

Once upon a time, it was presumed that the moons of the outer planets, so far from the sun and so close to the origins of the solar system, would be boring ice balls, geologically and in every other way dead.

But then Voyager 2 spotted volcanoes spraying fountains of sulfur from the surface of Jupiter’s innermost moon, Io. On close inspection, Saturn’s rings — the jewels of the solar system — dissolved into 10,000 grooves, like a vinyl record’s, braided, kinked and patrolled by tiny moonlets.

Voyager 1 plumbed a fat, smoggy atmosphere of Titan, where nitrogen and methane rains fall on a frozen slush pile of hydrocarbons and oily lakes, and then headed off toward interstellar space.

Voyager 2 cruised on to Uranus, mysteriously tipped on its axis and surrounded by rings that make it look like a bull’s eye.

The probe passed the restful methane blue of Neptune, besmirched by a dark spot, and its moon Triton, an ice rock flowing like soft ice cream with geysering nitrogen.

I’ve never had more fun as a science writer than during those weeklong encounters in Pasadena, when my colleagues and I — a little older and grayer ourselves, humbler but no wiser about the tricks that nature might be up to out there in the realm of dark and ice — gathered to watch the scientists watch their new worlds.

The television screens in the press room showed the latest images as they came in from the Voyager spacecraft. We had the same view as the scientists.

If on some distant world there had been a sign saying “Drink Coke,” or a pyramid, what we liked to call “the press room imaging team” would have had a chance to see it first.

Casting aside years of learned reserve and an addiction to speaking and writing in the passive voice, Voyager scientists had to parade to daily news briefings and venture explanations that they knew they would have to take back a few days later about things they (and we) had seen for the first time only a few hours before.

Part of the joy of “The Farthest: Voyager in Space,” a documentary to air on PBS on Wednesday, is reliving those moments of bafflement and intellectual ambition.

It was at the Voyager encounters that I first got to know my colleagues in the newspaper business, and learned by going out to dinner with them that they could drink me under the table before the appetizers arrived.

Other nights were spent in the bluesy, smoky company of science writers and planetary astronomers listening to the space ballads of Jonathan Eberhart, the late correspondent for Science News and a well-known folk singer. A rock band named for a feature of Titan, The Titan Equatorial Band, played at parties and gatherings.

The music stopped the morning after Voyager 2 passed by Uranus, on Jan. 28, 1986, when the Space Shuttle Challenger blew up with seven astronauts aboard, including Christa McAuliffe, the teacher in space.

That morning the televisions in a hushed newsroom at J.P.L. had Uranus on one screen and the Y-shaped cloud of the explosion on the other. By noon, my newspaper friends had packed their bags and headed for Houston or Cape Canaveral.

Voyager 2 went on. By the time it reached Neptune — the gatekeeper of our planetary realm, now that Pluto doesn’t count — the engineers at J.P.L. had enlisted antennas around the Earth to listen in unison, catching the trickle of data bits flowing from almost three billion miles away.

Chuck Berry, whose music was included on the spacecraft records, came to the lab to play for a Voyager farewell party.

There would be one last act. In 1990, as it ascended the void, Voyager 1’s crew commanded it to turn its cameras backward and snap a family portrait of the worlds it was leaving forever behind.

The Earth appears on this picture as the famous “pale blue dot” in a wash of scattered sunlight, a “mote of dust suspended in a sunbeam,” as the astronomer and cosmic sage Carl Sagan later described it.

Voyagers’ cameras are now turned off, but the probes continue to report back on the conditions in deepest space.

In October 2012, magnetic field and cosmic ray measurements indicated that Voyager 1 had reached the edge of the magnetic bubble that the sun extends like an umbrella over the planets, blocking outside radiation.

Voyager 1 was in interstellar space, the first human artifact to escape the solar system. It and its twin will go on circling the galaxy, long after it has ceased speaking to us.

In the fullness of galactic time, the Voyagers may be found, but by then the human race may be long extinct. The Voyager record might be the only physical remnant, the last lonely evidence that we, too, once lived in this city of stars, among these islands of ice and rock.

Back then, we were looking forward to an exploration of space that would go on forever. It was magic, and we were all on the spaceship."

[End of Article]
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The Voyager program is an American scientific program that employs two robotic probes, Voyager 1 and Voyager 2, to study the outer Solar System. The probes were launched in 1977 to take advantage of a favorable alignment of Jupiter, Saturn, Uranus and Neptune.

Although their original mission was to study only the planetary systems of Jupiter and Saturn, Voyager 2 continued on to Uranus and Neptune. The Voyagers now explore the outer boundary of the heliosphere in interstellar space; their mission has been extended three times and they continue to transmit useful scientific data. Neither Uranus nor Neptune has been visited by a probe other than Voyager 2.

On 25 August 2012, data from Voyager 1 indicated that it had become the first human-made object to enter interstellar space, traveling "further than anyone, or anything, in history". As of 2013, Voyager 1 was moving with a velocity of 17 kilometers per second (11 mi/s) relative to the Sun.

Data and photographs collected by the Voyagers' cameras, magnetometers and other instruments, revealed unknown details about each of the four giant planets and their moons.

Close-up images from the spacecraft charted Jupiter’s complex cloud forms, winds and storm systems and discovered volcanic activity on its moon Io.

Saturn’s rings were found to have enigmatic braids, kinks and spokes and to be accompanied by myriad "ringlets".

At Uranus, Voyager 2 discovered a substantial magnetic field around the planet and ten more moons.

Its flyby of Neptune uncovered three rings and six hitherto unknown moons, a planetary magnetic field and complex, widely distributed auroras. Voyager 2 is the only spacecraft to have visited the two ice giants.

The Voyager spacecraft were built at the Jet Propulsion Laboratory in Southern California and they were funded by the National Aeronautics and Space Administration (NASA), which also financed their launches from Cape Canaveral, Florida, their tracking and everything else concerning the probes.

The cost of the original program was $865 million, with the later-added Voyager Interstellar Mission costing an extra $30 million.

Click on any of the following blue hyperlinks for about NASA's Voyager Program:








Mars Landing of the Curiosity Rover (2012)
YouTube Video: Curiosity Has Landed
YouTube Video: Curiosity Rover Report (August 2015): Three Years on Mars!
(See also YouTube Videos listed at bottom of this Topic)
Pictured Below: This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Big Sky" site, where its drill collected the mission's fifth taste of Mount Sharp. The scene combines dozens of images taken during the 1,126th Martian day, or sol, of Curiosity's work during Mars (Oct. 6, 2015, PDT), by the Mars Hand Lens Imager (MAHLI) camera at the end of the rover's robotic arm. The rock drilled at this site is sandstone in the Stimson geological unit inside 

Curiosity is a car-sized rover designed to explore Gale Crater on Mars as part of NASA's Mars Science Laboratory mission (MSL).

Curiosity was launched from Cape Canaveral on November 26, 2011, at 15:02 UTC aboard the MSL spacecraft and landed on Aeolis Palus in Gale Crater on Mars on August 6, 2012, 05:17 UTC. 

The Bradbury Landing site was less than 2.4 km (1.5 mi) from the center of the rover's touchdown target after a 560 million km (350 million mi) journey. The rover's goals include an investigation of the Martian climate and geology; assessment of whether the selected field site inside Gale Crater has ever offered environmental conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for human exploration.

In December 2012, Curiosity's two-year mission was extended indefinitely. On August 5, 2017, NASA celebrated the fifth anniversary of the Curiosity rover landing and related exploratory accomplishments on the planet Mars. 

The rover is still operational, and as of June 25, 2018, Curiosity has been on Mars for 2092 sols (2149 total days) since landing on August 6, 2012.

Curiosity's design will serve as the basis for the planned Mars 2020 rover.

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Cape Canaveral Air Force Base
YouTube Video of the Launch of Apollo 11
Pictured below: ​Saturn [SA-3] lifting off from Launch Complex 34 Photo courtesy of NASA

Cape Canaveral Air Force Station (CCAFS) (known as Cape Kennedy Air Force Station from 1963 to 1973) is an installation of the United States Air Force Space Command's 45th Space Wing.

CCAFS is headquartered at the nearby Patrick Air Force Base, and located on Cape Canaveral in Brevard County, Florida, CCAFS.

The station is the primary launch head of America's Eastern Range with three launch pads currently active (Space Launch Complexes 37B, 40, and 41).

Popularly known as "Cape Kennedy" from 1963 to 1973, and as "Cape Canaveral" from 1949 to 1963 and from 1973 to the present, the facility is south-southeast of NASA's Kennedy Space Center on adjacent Merritt Island, with the two linked by bridges and causeways.

The Cape Canaveral Air Force Station Skid Strip provides a 10,000-foot (3,000 m) runway close to the launch complexes for military airlift aircraft delivering heavy and outsized payloads to the Cape.

A number of American space exploration pioneers were launched from CCAFS, including: 
CCAFS was also the launch site for:
Portions of the base have been designated a National Historic Landmark for their association with the early years of the American space program.

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Jet Propulsion Laboratory (NASA) (JPL Website)
YouTube Video about the Jet Propulsion Laboratory: NASA Mars InSight Overview
(InSight is more than a Mars mission. Its team members hope to unlock the mysteries of the formation and evolution of rocky planets, including Earth. For more about the mission, click here.

Pictured below: A Ticket to Explore JPL is an annual event where NASA’s Jet Propulsion Laboratory in Pasadena, California, opens its doors to the public once a year. Visitors are offered a behind-the-scenes look and interactive demonstrations. You must reserve tickets for JPL’s Open House in advance. Other opportunities to experience JPL include their monthly von Karman Lecture series and weekday JPL Tours.

The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in Pasadena, California, with large portions of the campus in La Cañada Flintridge, California.

Founded in 1930s, the JPL is currently owned by NASA and managed by the nearby California Institute of Technology (Caltech) for NASA. The laboratory's primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA's Deep Space Network.

Among the laboratory's major active projects are:
JPL is also responsible for managing the JPL Small-Body Database, and provides physical data and lists of publications for all known small Solar System bodies.

The JPL's Space Flight Operations Facility and Twenty-Five-Foot Space Simulator are designated National Historic Landmarks.

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Vandenberg Air Force Base
YouTube Video: Atlas V NROL-35 Launch Highlights
​Pictured: Titan IV rocket launch from Space Launch Complex-4 East, Vandenberg AFB, 19 October 2005

Vandenberg Air Force Base (IATA: VBG, ICAO: KVBG, FAA LID: VBG) is a United States Air Force Base 9.2 miles (14.8 km) northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command (AFSPC).

Vandenberg AFB is a Department of Defense space and missile testing base, with a mission of placing satellites into polar orbit from the West Coast using expendable boosters (Pegasus, Taurus, Minotaur, Atlas V, and Delta IV) and reusable boosters (SpaceX's Falcon 9). Wing personnel also support the Service's LGM-30G Minuteman III Intercontinental Ballistic Missile Force Development Evaluation program.

In addition to its military mission, the base also leases launch pad facilities to SpaceX (SLC-4E), as well as 100 acres (40 ha) leased to the California Spaceport in 1995.
Established in 1941, the base is named in honor of former Air Force Chief of Staff General Hoyt Vandenberg.

Units:
​See also: List of Vandenberg Air Force Base Launch Facilities

The host unit at Vandenberg AFB is the 30th Space Wing. The 30th SW is home to the Western Range, manages Department of Defense space and missile testing, and places satellites into near-polar orbits from the West Coast.

Wing personnel also support the Air Force's Minuteman III Intercontinental Ballistic Missile Force Development Test and Evaluation program. The Western Range begins at the coastal boundaries of Vandenberg and extends westward from the California coast to the Western Pacific, including sites in Hawaii. Operations involve dozens of federal and commercial interests.

The wing is organized into operations, launch, mission support and medical groups, along with several directly assigned staff agencies:
Space and Missile Heritage Center:

The Space and Missile Heritage Center is located at Space Launch Complex 10, site of the first IRBM tests of the Thor and Discoverer (aka Corona spy satellite) series of launches. It is Vandenberg's only National Historic Landmark that is open for regularly scheduled tours through the 30th Space Wing's Public Affairs office.

The Center preserves and displays artifacts and memorabilia to interpret the evolution of missile and spacelift activity at Vandenberg from the beginning of the Cold War through current non-classified developments in military, commercial, and scientific space endeavors.

The current display area is made up of two exhibits, the "Chronology of the Cold War" and the "Evolution of Technology". The exhibits incorporate a combination of launch complex models, launch consoles, rocket engines, re-entry vehicles, audiovisual and computer displays as well as hands-on interaction where appropriate. There are plans to evolve the center in stages from the current exhibit areas as restorations of additional facilities are completed.

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Space Shuttle Program (1972-2011) featuring the Space Shuttle, along with a List of: YouTube Video: Every Space Shuttle ever launched, in order
(NASA's pioneering reusable Space Transportation System (STS) was in operation for 30 years. 355 men and women flew on the five Space Shuttles over 135 missions. This video shows all of them.)
YouTube Video: Last Blast Off of the Space Shuttle Program
The beginning of the end of the shuttle era commenced with the lift-off of Atlantis and its crew of 4 at 11:29am EDT July 8, 2011.
Pictured below: The SLS is designed to hoist the Orion Multi-purpose Crew Vehicle, along with science experiments and critical supplies, to Earth's orbit and, eventually, way beyond. See more space exploration pictures. Courtesy of © 2011 HOWSTUFFWORKS
Click here for a List of Space Shuttle Missions.
Click here for a List of Space Shuttle Crews.
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​The Space Shuttle program was the fourth human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. Its official name, Space Transportation System (STS), was taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development.

The Space Shuttle—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank—carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and land like a glider at either the Kennedy Space Center or Edwards Air Force Base.

The Shuttle is the only winged manned spacecraft to have achieved orbit and landing, and the only reusable manned space vehicle that has ever made multiple flights into orbit (the Russian shuttle Buran was very similar and was designed to have the same capabilities but made only one unmanned spaceflight before it was cancelled).

The Shuttle missions involved carrying large payloads to various orbits (including segments to be added to the International Space Station (ISS)), providing crew rotation for the space station, and performing service missions.

The orbiter also recovered satellites and other payloads (e.g., from the ISS) from orbit and returned them to Earth, though its use in this capacity was rare. Each vehicle was designed with a projected lifespan of 100 launches, or 10 years' operational life, though original selling points on the shuttles were over 150 launches and over a 15-year operational span with a 'launch per month' expected at the peak of the program, but extensive delays in the development of the International Space Station never created such a peak demand for frequent flights.

Although the concept had been explored since the late 1960s, the program formally commenced in 1972, and was the sole focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. The Shuttle was originally conceived of and presented to the public in 1972 as a 'Space Truck' which would, among other things, be used to build a United States space station in low Earth orbit during the 1980s and then be replaced by a new vehicle by the early 1990s.

The stalled plans for a U.S. space station evolved into the International Space Station and were formally initiated in 1983 by U.S. President Ronald Reagan, but the ISS suffered from long delays, design changes and cost over-runs and forced the service life of the Space Shuttle to be extended several times until 2011 when it was finally retired—serving twice as long than it was originally designed to do.

In 2004, according to the President George W. Bush's Vision for Space Exploration, use of the Space Shuttle was to be focused almost exclusively on completing assembly of the ISS, which was far behind schedule at that point.

The first experimental orbiter Enterprise was a high-altitude glider, launched from the back of a specially modified Boeing 747, only for initial atmospheric landing tests (ALT). Enterprise's first test flight was on February 18, 1977, only five years after the Shuttle program was formally initiated; leading to the launch of the first space-worthy shuttle Columbia on April 12, 1981 on STS-1.

The Space Shuttle program finished with its last mission, STS-135 flown by Atlantis, in July 2011, retiring the final Shuttle in the fleet. The Space Shuttle program formally ended on August 31, 2011.

Since the Shuttle's retirement, many of its original duties are performed by an assortment of government and private vessels. The European ATV Automated Transfer Vehicle supplied the ISS between 2008 and 2015. Classified military missions are being flown by the US Air Force's unmanned space plane, the X-37B.

By 2012, cargo to the International Space Station was already being delivered commercially under NASA's Commercial Resupply Services by SpaceX's partially reusable Dragon spacecraft, followed by Orbital Sciences' Cygnus spacecraft in late 2013. Crew service to the ISS is currently provided by the Russian Soyuz while work on the Commercial Crew Development program proceeds; the first crewed flight of this is planned for December 2018, on the SpaceX Falcon 9 with Dragon 2 crew capsule. For missions beyond low Earth orbit, NASA is building the Space Launch System and the Orion spacecraft.

Click on any of the  following blue hyperlinks for more about the Space Shuttle Program: ___________________________________________________________________________

The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration (NASA), as part of the Space Shuttle program (above).

The space shuttle's official program name was Space Transportation System (STS), taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. 

The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. In addition to the prototype whose completion was cancelled, five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida.

Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST); conducted science experiments in orbit; and participated in construction and servicing of the International Space Station. The Shuttle fleet's total mission time was 1322 days, 19 hours, 21 minutes and 23 seconds.

Shuttle components included the Orbiter Vehicle (OV) with three clustered Rocketdyne RS-25 main engines, a pair of recoverable solid rocket boosters (SRBs), and the expendable external tank (ET) containing liquid hydrogen and liquid oxygen.

The Space Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System (OMS) engines.

At the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a runway landing, usually to the Shuttle Landing Facility at Kennedy Space Center, Florida or Rogers Dry Lake in Edwards Air Force Base, California.

After landing at Edwards, the orbiter was flown back to the KSC on the Shuttle Carrier Aircraft, a specially modified version of the Boeing 747.

The first orbiter, Enterprise, was built in 1976, used in Approach and Landing Tests and had no orbital capability. Four fully operational orbiters were initially built: Columbia, Challenger, Discovery, and Atlantis. Of these, two were lost in mission accidents: Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed. (See later topic below, covering both disasters.)

A fifth operational (and sixth in total) orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis's final flight on July 21, 2011. The U.S. has since relied primarily on the Russian Soyuz spacecraft to transport supplies and astronauts to the International Space Station.

Click on any of the following blue hyperlinks for more about the Space Shuttle program:





​

Space Shuttle Challenger Disaster (1986)
YouTube Video of the 1986 Challenger Space Shuttle Disaster by CNN
Pictured below: Photo montage of the Space Shuttle Challenger

On January 28, 1986, the NASA shuttle orbiter mission STS-51-L and the tenth flight of Space Shuttle Challenger (OV-99) broke apart 73 seconds into its flight, killing all seven crew members, which consisted of five NASA astronauts and two payload specialists.

The spacecraft disintegrated over the Atlantic Ocean, off the coast of Cape Canaveral, Florida, at 11:39 EST. The disintegration of the vehicle began after a joint in its right solid rocket booster (SRB) failed at liftoff. The failure was caused by the failure of O-ring seals used in the joint that were not designed to handle the unusually cold conditions that existed at this launch.

The seals' failure caused a breach in the SRB joint, allowing pressurized burning gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB aft field joint attachment hardware and external fuel tank. This led to the separation of the right-hand SRB's aft field joint attachment and the structural failure of the external tank. Aerodynamic forces broke up the orbiter.

The crew compartment and many other vehicle fragments were eventually recovered from the ocean floor after a lengthy search and recovery operation. The exact timing of the death of the crew is unknown; several crew members are known to have survived the initial breakup of the spacecraft.

The shuttle had no escape system, and the impact of the crew compartment with the ocean surface was too violent to be survivable.

The disaster resulted in a 32-month hiatus in the shuttle program and the formation of the Rogers Commission, a special commission appointed by United States President Ronald Reagan to investigate the accident. The Rogers Commission found NASA's organizational culture and decision-making processes had been key contributing factors to the accident, with the agency violating its own safety rules.

NASA managers had known since 1977 that contractor Morton-Thiokol's design of the SRBs contained a potentially catastrophic flaw in the O-rings, but they had failed to address this problem properly. NASA managers also disregarded warnings from engineers about the dangers of launching posed by the low temperatures of that morning, and failed to adequately report these technical concerns to their superiors.

Approximately 17 percent of Americans witnessed the launch live because of the presence of Payload Specialist Christa McAuliffe, who would have been the first teacher in space. Media coverage of the accident was extensive: one study reported that 85 percent of Americans surveyed had heard the news within an hour of the accident.

The Challenger disaster has been used as a case study in many discussions of engineering safety and workplace ethics.

Click on any of the following blue hyperlinks for more about the Challenger Space Shuttle Disaster:







Space Shuttle Columbia Disaster (2003)
YouTube Video of Space Shuttle Columbia Disaster: Final descent - BBC

On February 1, 2003, the Space Shuttle Columbia disintegrated upon reentering Earth's atmosphere, killing all seven crew members. The disaster was the second fatal accident in the Space Shuttle program after Space Shuttle Challenger (see preceding topic), which broke apart and killed the seven-member crew 73 seconds after liftoff in 1986.

During the launch of STS-107, Columbia's 28th mission, a piece of foam insulation broke off from the Space Shuttle external tank and struck the left wing of the orbiter.

A few previous shuttle launches had seen damage ranging from minor to nearly catastrophic from foam shedding, but some engineers suspected that the damage to Columbia was more serious. NASA managers limited the investigation, reasoning that the crew could not have fixed the problem if it had been confirmed.

When Columbia re-entered the atmosphere of Earth, the damage allowed hot atmospheric gases to penetrate the heat shield and destroy the internal wing structure, which caused the spacecraft to become unstable and break apart.
​
After the disaster, Space Shuttle flight operations were suspended for more than two years, as they had been after the Challenger disaster. Construction of the International Space Station (ISS) was put on hold; the station relied entirely on the Russian Roscosmos State Corporation for resupply for 29 months until Shuttle flights resumed with STS-114 and 41 months for crew rotation until STS-121.

Several technical and organizational changes were made, including adding a thorough on-orbit inspection to determine how well the shuttle's thermal protection system had endured the ascent, and keeping a designated rescue mission ready in case irreparable damage was found.

Except for one final mission to repair the Hubble Space Telescope, subsequent shuttle missions were flown only to the ISS so that the crew could use it as a haven in case damage to the orbiter prevented safe reentry.

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Kennedy Space Center
YouTube Video of Kennedy Space Center Visitor Complex Overview
Pictured below: Aerial view of KSC Headquarters looking south

The John F. Kennedy Space Center (KSC) is one of ten National Aeronautics and Space Administration field centers. Since December 1968, Kennedy Space Center has been NASA's primary launch center of human spaceflight.

Launch operations for the Apollo, Skylab and Space Shuttle programs were carried out from Kennedy Space Center Launch Complex 39 and managed by KSC. Located on the east coast of Florida, KSC is adjacent to Cape Canaveral Air Force Station (CCAFS). The management of the two entities work very closely together, share resources, and even own facilities on each other's property.

Though the first Apollo flights, and all Project Mercury and Project Gemini flights took off from CCAFS, the launches were managed by KSC and its previous organization, the Launch Operations Directorate. 

Starting with the fourth Gemini mission, the NASA launch control center in Florida (Mercury Control Center, later the Launch Control Center) began handing off control of the vehicle to the Mission Control Center shortly after liftoff; in prior missions it held control throughout the entire mission.

Additionally, the center manages launch of robotic and commercial crew missions and researches food production and In-Situ Resource Utilization for off-Earth exploration.

Since 2010, the center has worked to become a multi-user spaceport through industry partnerships, even adding a new launch pad (LC-39C) in 2015.

There are about 700 facilities grouped across the center's 144,000 acres. Among the unique facilities at KSC are the 525 ft tall Vehicle Assembly Building for stacking NASA's largest rockets, the Operations and Checkout Building, which houses the astronaut crew quarters, and 3-mile-long Shuttle Landing Facility. There is also a Visitor Complex open to the public on site.

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Edwards Air Force Base
YouTube Video of Space Shuttle Discovery Landing STS-128 Edwards Air Force Base
Pictured below: A 461st Flight Test Squadron F-35 Lightning II, marked AA-1, lands at Edwards Air Force Base

​Edwards Air Force Base (AFB) (IATA: EDW, ICAO: KEDW, FAA LID: EDW) is a United States Air Force installation located in Kern County in southern California, about 22 miles (35 km) northeast of Lancaster and 15 miles (24 km) east of Rosamond.

Edwards AFB is the home of the Air Force Test Center, Air Force Test Pilot School, and NASA's Armstrong Flight Research Center. It is the Air Force Materiel Command center for conducting and supporting research and development of flight, as well as testing and evaluating aerospace systems from concept to combat. It is also hosts many test activities conducted by America's commercial aerospace industry.

Click on any of the following blue hyperlinks for more about Edwards Air Force Base: ​







International Space Station Pictured below: A rearward view of the International Space Station backdropped by the limb of the Earth. In view are the station's four large, gold-coloured solar array wings, two on either side of the station, mounted to a central truss structure. Further along the truss are six large, white radiators, three next to each pair of arrays. In between the solar arrays and radiators is a cluster of pressurised modules arranged in an elongated T shape, also attached to the truss. A set of blue solar arrays are mounted to the module at the aft end of the cluster.
The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component was launched into orbit in 1998, with the first long-term residents arriving in November 2000.[7] It has been inhabited continuously since that date.

The last pressurized module was fitted in 2011, and an experimental inflatable space habitat was added in 2016. The station is expected to operate until 2030. Development and assembly of the station continues, with several new elements scheduled for launch in 2019.

The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. The ISS consists of pressurized habitation modules, structural trusses, solar arrays, radiators, docking ports, experiment bays and robotic arms. ISS components have been launched by Russian Proton and Soyuz rockets and American Space Shuttles.

The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology, and other fields. The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars.

The ISS maintains an orbit with an altitude of between 330 and 435 km (205 and 270 mi) by means of reboost manoeuvres using the engines of the Zvezda module or visiting spacecraft. It circles the Earth in roughly 92 minutes and completes 15.5 orbits per day.

The ISS program is a joint project between five participating space agencies: 
  1. NASA (United States), 
  2. Roscosmos (Russia), 
  3. JAXA (Japan), 
  4. ESA (Europe),
  5. and CSA (Canada).

The ownership and use of the space station is established by intergovernmental treaties and agreements. The station is divided into two sections, the Russian Orbital Segment (ROS) and the United States Orbital Segment (USOS), which is shared by many nations.

As of January 2018, operations of the American segment were funded until 2025. Roscosmos has endorsed the continued operation of ISS through 2024, but has proposed using elements of the Russian segment to construct a new Russian space station called OPSEK.

The ISS is the ninth space station to be inhabited by crews, following the Soviet and later Russian Salyut, Almaz, and Mir stations as well as Skylab from the US. The station has been continuously occupied for 18 years and 188 days since the arrival of Expedition 1 on 2 November 2000 (see next topic below). This is the longest continuous human presence in low Earth orbit, having surpassed the previous record of 9 years and 357 days held by Mir.

The ISS has been visited by astronauts, cosmonauts and space tourists from 18 different nations. After the American Space Shuttle program ended in 2011, Soyuz rockets became the only provider of transport for astronauts at the ISS.

The station is serviced by a variety of visiting spacecraft:
The Dragon spacecraft allows the return of pressurized cargo to Earth (downmass), which is used for example to repatriate scientific experiments for further analysis. The Soyuz return capsule has minimal downmass capability next to the astronauts.

As of 14 March 2019, 236 people from 18 countries had visited the space station, many of them multiple times:
  • The United States sent 149 people,
  • Russia sent 47,
  • nine were Japanese,
  • eight were Canadian,
  • five were Italian,
  • four were French,
  • three were German,
  • and there were one each from:
    • Belgium,
    • Brazil,
    • Denmark,
    • Kazakhstan,
    • Malaysia,
    • the Netherlands,
    • South Africa,
    • South Korea,
    • Spain,
    • Sweden,
    • and the United Kingdom.

Click on any of the following blue hyperlinks for more about the International Space Station:







​Expedition 1 Space Station
YouTube Video about ISS: Expedition One Launch 2000-10-31
​​Pictured below: The ISS during Expedition 1, seen during the approach of STS-97, the first Shuttle mission to visit the inhabited space station
Expedition 1 was the first long-duration stay on the International Space Station (ISS). The three-person crew stayed aboard the station for 136 days, from November 2000 to March 2001. It was the beginning of an uninterrupted human presence on the station which continues as of May 2019. Expedition 2, which also had three crew members, immediately followed Expedition 1.

The official start of the expedition occurred when the crew docked to the station on 2 November 2000, aboard the Russian spacecraft Soyuz TM-31, which had launched two days earlier.

During their mission, the Expedition 1 crew activated various systems on board the station, unpacked equipment that had been delivered, and hosted three visiting Space Shuttle crews and two unmanned Russian Progress resupply vehicles. The crew was very busy throughout the mission, which was declared a success.

The three visiting Space Shuttles brought equipment, supplies, and key components of the space station. The first of these, STS-97, docked in early December 2000, and brought the first pair of large U.S. photovoltaic arrays, which increased the station's power capabilities fivefold. 

The second visiting shuttle mission was STS-98, which was docked in mid-February 2001 and delivered the US$1.4 billion research module Destiny, which increased the mass of the station beyond that of Mir for the first time. 

Mid-March 2001 saw the final shuttle visit of the expedition, STS-102, whose main purpose was to exchange the Expedition 1 crew with the next three-person long-duration crew, Expedition 2. The expedition ended when Discovery undocked from the station on 18 March 2001.

The Expedition 1 crew consisted of an American commander and two Russians. The commander, Bill Shepherd, had been in space three times before, all on shuttle missions which lasted at most a week. The Russians, Yuri Gidzenko and Sergei K. Krikalev, both had previous long-duration spaceflights on Mir, with Krikalev having spent over a full year in space.

Click on any of the following blue hyperlinks for more about Expedition 1:






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James Webb Space Telescope [See also YouTube Videos at the end of this Topic]
Pictured below: Highlights From the James Webb Space Telescope’s Long-Awaited Launch (NY Times)
This is an update (December 26, 2021) to the original topic concerning NASA's James Webb Telescope: The satellite was officially launched Christmas Day, December 25, 2021]:

The James Webb Space Telescope (JWST) is a space telescope developed by NASA with contributions from the European Space Agency (ESA), and the Canadian Space Agency (CSA). It is intended to succeed the Hubble Space Telescope as NASA's flagship mission in astrophysics. 

JWST was launched on 25 December 2021 on Ariane flight VA256. It is designed to provide improved infrared resolution and sensitivity over Hubble, and will enable a broad range of investigations across the fields of astronomy and cosmology, including observations of some of the most distant events and objects in the Universe such as the formation of the first galaxies, and allowing detailed atmospheric characterization of potentially habitable exoplanets.

The primary mirror of JWST, the Optical Telescope Element, consists of 18 hexagonal mirror segments made of gold-plated beryllium, which combine to create a 6.5 m (21 ft) diameter mirror – considerably larger than Hubble's 2.4 m (7 ft 10 in) mirror.

Unlike the Hubble telescope, which observes in the near ultraviolet, visible, and near infrared (0.1–1.0 μm) spectra, JWST will observe in a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm). This will enable it to observe high-redshift objects that are too old and too distant for Hubble to observe. 

The telescope must be kept very cold to observe in the infrared without interference, so it will be deployed in space near the Sun–Earth L2 Lagrange point, about 1.5 million kilometers (930,000 mi) from Earth (0.01 au – 3.9 times the distance to the Moon). A large sunshield made of silicon- and aluminum-coated Kapton will keep its mirror and instruments below 50 K (−223 °C; −370 °F).

The NASA Goddard Space Flight Center (GSFC) in Maryland managed the development, and the Space Telescope Science Institute is operating Webb. The prime contractor was Northrop Grumman. The telescope is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 and played an integral role in the Apollo program.

​Development began in 1996 for a launch that was initially planned for 2007 with a US$500 million budget. There were numerous delays and cost overruns, including a major redesign in 2005, a ripped sunshield during a practice deployment, a recommendation from an independent review board, the COVID-19 pandemic, issues with the Ariane 5 rocket and the telescope itself, and communications issues between the telescope and the launch vehicle. 

Concerns among the involved scientists and engineers about the launch and deployment of the telescope have been well described.

Construction was completed in late 2016, at which point an extensive testing phase began. JWST was launched at 12:20 UTC on 25 December 2021 by an Ariane 5 launch vehicle from Kourou, French Guiana, on the northeastern coast of South America, and was released from the upper stage 27 minutes later. 

The telescope was confirmed to be receiving power, and as of December 2021 is traveling to its target destination.

Click on any of the following blue hyperlinks for more about the James Webb Telescope:







Human Space Flights, including a List of Human Space Flights Pictured below: This is a printable version of space shuttle Atlantis' orbiter tribute, or OV-104, which hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. In the lower-left corner, it features Atlantis soaring above Earth and threaded through the design are the mission patches for each of Atlantis' flights. Atlantis' accomplishments include seven missions to the Russian space station Mir and several assembly, construction and resupply missions to the International Space Station. Atlantis also flew the last Hubble Space Telescope servicing mission on STS-125.
Human spaceflight (also referred to as crewed spaceflight or manned spaceflight) is space travel with a crew or passengers aboard the spacecraft. Spacecraft carrying people may be operated directly, by human crew, or it may be either remotely operated from ground stations on Earth or be autonomous, able to carry out a specific mission with no human involvement.

The first human spaceflight was launched by the Soviet Union on 12 April 1961 as a part of the Vostok program, with cosmonaut Yuri Gagarin aboard. Humans have been continuously present in space for 18 years and 196 days on the International Space Station. All human spaceflight has so far been human-piloted, with the first autonomous human-carrying spacecraft under design starting in 2015.

Russia and China have human spaceflight capability with the Soyuz program and Shenzhou program.

In the United States, SpaceShipTwo reached the edge of space in 2018; this was the first crewed spaceflight from the USA since the Space Shuttle retired in 2011. Currently, all expeditions to the International Space Station use Soyuz vehicles, which remain attached to the station to allow quick return if needed. The United States is developing commercial crew transportation to facilitate domestic access to ISS and low Earth orbit, as well as the Orion vehicle for beyond-low-Earth-orbit applications.

While spaceflight has typically been a government-directed activity, commercial spaceflight has gradually been taking on a greater role. The first private human spaceflight took place on 21 June 2004, when SpaceShipOne conducted a suborbital flight, and a number of non-governmental companies have been working to develop a space tourism industry.

NASA has also played a role to stimulate private spaceflight through programs such as Commercial Orbital Transportation Services (COTS) and Commercial Crew Development (CCDev). With its 2011 budget proposals released in 2010, the Obama administration moved towards a model where commercial companies would supply NASA with transportation services of both people and cargo transport to low Earth orbit.

The vehicles used for these services could then serve both NASA and potential commercial customers. Commercial resupply of ISS began two years after the retirement of the Shuttle, and commercial crew launches could begin by 2019.

Click on any of the following blue hyperlinks for more about Human Spaceflight: ___________________________________________________________________________


This is a list of all human spaceflights throughout history. Beginning in 1961 with the flight of Yuri Gagarin aboard Vostok 1, human spaceflight occurs when a human crew flies a spacecraft into outer space. Human spaceflight is distinguished from spaceflight generally, which entails both crewed and uncrewed spacecraft.

There are two definitions of spaceflight. The Fédération Aéronautique Internationale (FAI), an international record-keeping body, defines the boundary between Earth's atmosphere and outer space at 100 kilometers above sea level. This boundary is known as the Kármán line.

Additionally, the United States military awards astronaut wings to qualified personnel who pilot a spaceflight above an altitude of 50 miles (80 km). Thirteen flights of the North American X-15 met the latter criteria, while only two met the former. This article is primarily concerned with the former international convention, and also lists flights which only satisfied the latter convention. Unless otherwise specified, "spaceflight" and related terms only apply to flights which went beyond the Kármán line.

As of the launch of Soyuz MS-12 on 14 March 2019, there have been 325 human spaceflight launch attempts, including three failed attempts which did not cross the Kármán line. These were the fatal Challenger disaster, and two non-fatal aborted Soyuz missions, T-10a and MS-10.

Another non-fatal aborted Soyuz mission, 18a, nevertheless crossed the Kármán line and therefore qualified as a sub-orbital spaceflight. Three missions successfully achieved human spaceflight, yet ended as fatal failures as their crews died during the return. These were Soyuz 1, Soyuz 11, and the Columbia disaster.

Uniquely, Soyuz 34 was launched uncrewed to the Salyut 6 space station, to provide a successful return vehicle for the crew of  Soyuz 32. Including Soyuz 34 gives a total of 326 attempted human spaceflights. 14 flights reached an apogee beyond 50 miles, but failed to go beyond 100 kilometers.

Click on any of the following blue hyperlinks for more about a List of Human Spaceflights:







Apollo Program (1961-1972)Pictured  below: The Saturn V (pronounced 'Saturn Five', popularly known as the Moon Rocket) was a multistage liquid-fuel expendable rocket used by NASA's Apollo and Skylab programs.
The Apollo program, also known as Project Apollo, was the third United States human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which succeeded in landing the first humans on the Moon from 1969 to 1972.

First conceived during Dwight D. Eisenhower's administration as a three-man spacecraft to follow the one-man Project Mercury which put the first Americans in space, Apollo was later dedicated to President John F. Kennedy's national goal of "landing a man on the Moon and returning him safely to the Earth" by the end of the 1960s, which he proposed in an address to Congress on May 25, 1961. It was the third US human spaceflight program to fly, preceded by the two-man Project Gemini conceived in 1961 to extend spaceflight capability in support of Apollo.

Kennedy's goal was accomplished on the Apollo 11 mission when astronauts Neil Armstrong and Buzz Aldrin landed their Apollo Lunar Module (LM) on July 20, 1969, and walked on the lunar surface, while Michael Collins remained in lunar orbit in the command and service module (CSM), and all three landed safely on Earth on July 24.

Five subsequent Apollo missions also landed astronauts on the Moon, the last in December 1972. In these six spaceflights, twelve men walked on the Moon.

Buzz Aldrin walked on the Moon with Neil Armstrong, on Apollo 11, July 20–21, 1969

Earthrise, an iconic image from the 1968 Apollo 8 mission, taken by astronaut William Anders Apollo ran from 1961 to 1972, with the first crewed flight in 1968. It achieved its goal of crewed lunar landing, despite the major setback of a 1967 Apollo 1 cabin fire that killed the entire crew during a pre-launch test.

After the first landing, sufficient flight hardware remained for nine follow-on landings with a plan for extended lunar geological and astrophysical exploration. Budget cuts forced the cancellation of three of these.

Five of the remaining six missions achieved successful landings, but the Apollo 13 landing was prevented by an oxygen tank explosion in transit to the Moon, which destroyed the service module's capability to provide electrical power, crippling the CSM's propulsion and life support systems. The crew returned to Earth safely by using the lunar module as a "lifeboat" for these functions.

Apollo used Saturn family rockets as launch vehicles, which were also used for an Apollo Applications Program, which consisted of Skylab, a space station that supported three crewed missions in 1973–74, and the Apollo–Soyuz Test Project, a joint US-Soviet Union Earth-orbit mission in 1975.

Apollo set several major human spaceflight milestones. It stands alone in sending crewed missions beyond low Earth orbit. Apollo 8 was the first crewed spacecraft to orbit another celestial body, while the final Apollo 17 mission marked the sixth Moon landing and the ninth crewed mission beyond low Earth orbit.

The program returned 842 pounds (382 kg) of lunar rocks and soil to Earth, greatly contributing to the understanding of the Moon's composition and geological history. The program laid the foundation for NASA's subsequent human spaceflight capability and funded construction of its Johnson Space Center and Kennedy Space Center. Apollo also spurred advances in many areas of technology incidental to rocketry and human spaceflight, including avionics, telecommunications, and computers.

Click on any of the following blue hyperlinks for more about the Apollo Space Program: ​







Apollo 11 (1969): Neil Armstrong & Buzz Aldrin are the first to walk on the Moon Pictured below: Apollo 11 astronauts Neil Armstrong and Edwin E. "Buzz" Aldrin, the first men to land on the moon, plant the U.S. flag on the lunar surface, July 20, 1969. Photo was made by a 16mm movie camera inside the lunar module, shooting at one frame per second. (Nasa via AP)
Apollo 11 was the spaceflight that landed the first two people on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin, both American, landed the Apollo Lunar Module Eagle on July 20, 1969, at 20:17 UTC.

Armstrong became the first person to step onto the lunar surface six hours later on July 21 at 02:56:15 UTC; Aldrin joined him 19 minutes later. They spent about two and a quarter hours together outside the spacecraft, and collected 47.5 pounds (21.5 kg) of lunar material to bring back to Earth. Command module pilot Michael Collins flew the command module Columbia alone in lunar orbit while they were on the Moon's surface.

Armstrong and Aldrin spent 21.5 hours on the lunar surface before rejoining Columbia in lunar orbit.

Apollo 11 was launched by a Saturn V rocket from Kennedy Space Center on Merritt Island, Florida, on July 16 at 13:32 UTC, and was the fifth crewed mission of NASA's Apollo program.

The Apollo spacecraft had three parts: a command module (CM) with a cabin for the three astronauts, and the only part that returned to Earth; a service module (SM), which supported the command module with propulsion, electrical power, oxygen, and water; and a lunar module (LM) that had two stages – a descent stage for landing on the Moon, and an ascent stage to place the astronauts back into lunar orbit.

After being sent to the Moon by the Saturn V's third stage, the astronauts separated the spacecraft from it and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved into Eagle and landed in the Sea of Tranquillity.

The astronauts used Eagle's ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned Eagle before they performed the maneuvers that propelled them out of lunar orbit on a trajectory back to Earth. They returned to Earth and splashed down in the Pacific Ocean on July 24 after more than eight days in space.

Armstrong's first step onto the lunar surface was broadcast on live TV to a worldwide audience. He described the event as "one small step for [a] man, one giant leap for mankind."

Apollo 11 effectively ended the Space Race and fulfilled a national goal proposed in 1961 by President John F. Kennedy: "before this decade is out, of landing a man on the Moon and returning him safely to the Earth."

Click on any of the following for more about Apollo 11:



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Space Exploration Technologies Corp. (SpaceX) Pictured below: NASA, SpaceX bringing astronaut launches back to home turf: Elon Musk’s SpaceX is the conductor and NASA the customer as businesses begin chauffeuring astronauts to the International Space Station.
Space Exploration Technologies Corp., trading as SpaceX, is an American aerospace manufacturer and space transportation services company headquartered in Hawthorne, California. It was founded in 2002 by Elon Musk with the goal of reducing space transportation costs to enable the colonization of Mars. SpaceX has developed several launch vehicles and the Dragon spacecraft.

SpaceX's achievements include:
SpaceX has flown 20 resupply missions to the International Space Station (ISS) under a partnership with NASA. NASA also awarded SpaceX a further development contract in 2011 to develop and demonstrate a human-rated Dragon, which would be used to transport astronauts to the ISS and return them safely to Earth. 

SpaceX conducted the maiden launch of its Dragon 2 spacecraft on a NASA-required demonstration flight (Crew Dragon Demo-1) on March 2, 2019, and launched its first crewed Dragon 2 on May 30, 2020.

In December 2015, a Falcon 9 accomplished a propulsive vertical landing. This was the first such achievement by a rocket for orbital spaceflight. In April 2016, with the launch of CRS-8, SpaceX successfully vertically landed the first stage on an ocean drone ship landing platform.

In May 2016, in another first, SpaceX again landed the first stage, but during a significantly more energetic geostationary transfer orbit mission. In March 2017, SpaceX became the first to successfully re-launch and land the first stage of an orbital rocket. In January 2020, with the third launch of the Starlink project, SpaceX became the largest commercial satellite constellation operator in the world.

In September 2016, Musk unveiled the Interplanetary Transport System, a privately funded launch system to develop spaceflight technology for use in crewed interplanetary spaceflight.

In 2018, Musk unveiled an updated configuration of the system, Starship, which is intended to become the primary SpaceX orbital vehicle after the early 2020s, as SpaceX has announced it intends to eventually replace its existing Falcon 9 launch vehicle and Dragon 2 fleet with Starship, even in the Earth-orbit satellite delivery market.

Starship is planned to be fully reusable and will be the largest rocket ever on its debut, scheduled for the early 2020s: see YouTube Video above for first launch on June 1, 2020.









The revolution in satellite technology means there are swarms of spacecraft no bigger than a loaf of bread in orbit (Washington Post 4/6/2021), thanks to Planet LabsPictured below: Planet Labs Earns ITU’s Praise for Good Orbital Stewardship
"The revolution in satellite technology means there are swarms of spacecraft no bigger than a loaf of bread in orbit"

The revolution in satellite technology means there are swarms of spacecraft no bigger than a loaf of bread in orbit

The avalanche was a stunning disaster, 247 million cubic feet of glacial ice and snow hurtling down the Tibetan mountain range at 185 mph. Nine people and scores of animals were killed in an event that startled scientists around the world.

As they researched why the avalanche occurred with such force, a team of researchers studying climate change pored over images taken in the days and weeks before and saw ominous cracks had begun to form in the ice and snow. Then, scanning photos of a nearby glacier, they noticed similar crevasses forming, touching off a scramble to warn local authorities that it was also about to come crashing down.

The images of the glaciers in 2016 came from a constellation of satellites no bigger than a shoe box, in orbit 280 miles up. Operated by San Francisco-based company Planet, the satellites, called Doves, weigh just over 10 pounds each and fly in “flocks” that today include 175 satellites. If one fails, the company replaces it, and as better batteries, solar arrays and cameras become available, the company updates its satellites the way Apple unveils a new iPhone.

The revolution in technology that transformed personal computing, put smart speakers in homes and gave rise to the age of artificial intelligence and machine learning is also transforming space. While rockets and human exploration get most of the attention, a quiet and often overlooked transformation has taken place in the way satellites are manufactured and operated. The result is an explosion of data and imagery from orbit.

Just as computers have shrunk from room-size behemoths to an iPhone that can fit in your pocket, satellites, too, have shrunk dramatically. Instead of being the size of a garbage truck, costing as much as $400 million, satellites now are often no larger than a microwave or even a loaf of bread. They cost a fraction of their predecessors, as little as $1 million or less, and can be mass-produced in factories, or in some cases a garage or college classroom.

As the size and cost of satellites have come down, their numbers have grown dramatically. The number of satellites in operation more than doubled from 1,381 in 2015 to 3,371 by the end of last year, according to Bryce Space and Technology, a consulting firm that tracks the industry. In 2011, there were only 39 satellites launched that weighed less than 1,322 pounds, or 600 kg, according to Bryce. By 2017, that was 338, and by last year, as SpaceX began putting up hundreds of its Starlink satellites designed to beam the Internet to rural areas, the number leaped to more than 1,200.

Now the industry has caught the attention of venture capitalists, who have been funding companies like Planet and others. In recent weeks, two satellite companies, Spire Global and Black Sky, have gone public through a merger known as a special purpose acquisition company, or SPAC.

Companies around the globe are working to develop small satellites. AAC Clyde Space, a Sweden-based company, has launched 10 satellites, some known as “cubesats,” for their small four-inch dimensions that weigh just a few pounds.

Like Planet, it offers “space as a service,” meaning people can buy access to the data from their satellites without worrying about launching or building the spacecraft themselves.

“You don’t have to get engaged in how to design the satellites, follow the production, take care of the testing,” said Rolf Hallencreutz, chairman of the company’s board. “You tell someone, ‘I need this kind of data.’ And we provide that data. For us, it changes the game because it allows us to serve multiple customers with the same constellation.”

The small satellite industry has also caught the attention of the Pentagon and intelligence agencies that would love to have swarms of small satellites, able to launch quickly and easily replaced, peering down behind enemy lines.

Planet was founded in 2010 by a trio of young scientists and engineers who were working at NASA’s Ames Research Center in Silicon Valley in what has become a classic tech start-up story: Young guys, driven by idealism, working late on their own time and harnessing their best nerdy tendencies to build their own satellites that were smaller and cheaper.

Yes, they did it in a garage in Cupertino, where Apple is headquartered. Since then, Planet has successfully launched 452 satellites and become the vanguard of the industry.

Now, it has more than 500 employees, and its total active users has grown an average of 40 percent per year since 2018.

The company’s satellites circle the globe in carefully designed orbits that “line-scan the Earth” — taking precise photographs of landmasses that together create an image of the planet every day. That gives scientists and researchers a look at conditions on the ground, so they can track changes to forests, coastal areas, shipping traffic and farmland in near real-time.

The images can help with border security, tracking refugees and disaster relief. Since the company has compiled a vast archive of images, stretching back years, its subscribers can visit the past, observing how it has changed — a searchable time lapse of Earth.

“The pictures don’t lie,” said Will Marshall, co-founder and chief executive of Planet.
Andreas Kaab, a glaciologist at the University of Oslo, discovered that as he was exploring what caused the devastating avalanche in Tibet. He and other scientists noticed “that the neighboring glacier seemed also to behave strangely,” he said in an email. They tried to reach local authorities in Tibet, going through contacts in China, to warn them that it was also about to collapse. But it took about a day before their message got through. By then, “the glacier had already collapsed,” he said.

Nobody was hurt, but the “case shows that high-resolution daily images are very important in disaster management, and they clearly have the potential for rapid early warnings.”

The Amazon Conservation Association, a nonprofit, uses the satellite imagery to monitor illegal logging and gold mines in the Andean Amazon. In the past, it used traditional government satellites that took pictures “every eight days, and if it’s cloudy, you have to wait another eight days,” said Matt Finer, director of the Monitoring of the Andean Amazon Project.

Those images had 30-meter resolution, which was decent but not great when you are trying to count trees. Then the European Space Agency launched a satellite with improved resolution, showing objects 10 meters across. But Planet’s satellites were a welcomed improvement, three-meter resolution and images that are available daily.

“This is real-time monitoring on the scale of hours or days,” Finer said. “A lot of times, we’re looking at an image of today or yesterday.”

​The government data was free, and the group had to pay a subscription fee for Planet’s images. But it was well worth it, Finer said. “You’re talking about leaps of improvement in your visual and analytical ability,” he said.

And using some of Planet’s next-generation satellites, which provide even higher resolutions, “we can see individual trees. We can see logging camps,” he said. Even the blue tarps that miners put up as makeshift roofs to protect from the rain and sun can be seen.

Given the high costs of satellites, traditional operators often rely on proven technology they know is reliable but may not be the most up-to-date, Marshall said.

“We’ve taken a different risk approach,” he said. “You’ve got more satellites coming in, and if a few of them fail, no big deal. That is what enables us to take the latest technology … and iterate fast.”

Small satellites are less expensive to launch — leading to a new model of small rockets designed to be less expensive and launch on demand. Rocket Lab, which launches out of New Zealand and soon out of the Eastern Shore of Virginia, is the leader in this relatively new market.

Later this year, it plans to launch a satellite the size of a microwave to the moon. The satellite would fly in the same orbit around the moon that NASA expects to use for the space station called Gateway it intends to operate there.

Other rocket companies are entering fast, including Virgin Orbit, the start-up founded by Richard Branson.

Instead of launching its rocket vertically from a pad, the company tethers its boosters to the wing of a 747 airplane that carries it 40,000 feet or so. The rocket is dropped, then fires its engines and is off.

That gives the company the ability to launch nearly anywhere there is a runway — and that is of interest not just to scientists and conservationists who want to get satellites up quickly, but to the Pentagon and intelligence agencies as well.

After Virgin Orbit’s first successful launch in January, Gen. Jay Raymond, the Space Force’s chief of space operations, congratulated the company on Twitter. And Will Roper, then the Air Force’s top acquisition and technology official, tweeted that the capability “is a big disruptor — and hopefully a deterrent — for future space conflicts. The satellite equivalent of keep an ace up your sleeve … err, plane.”

Satellites already provide missile warning, GPS, communications and reconnaissance and guide precision munitions. But the smaller and more capable they become, the more the Pentagon is interested in using them.

“These small satellites are now mission-critical,” said Dan Hart, the chief executive of Virgin Orbit.

Another key benefit is that if one malfunctions, or is taken down by an adversary, “we can very quickly put another one up, and we can do it from anywhere on Earth,” he said. Using a 747 as a launcher, the Pentagon could also do it surreptitiously.

​Much of the increase of satellites in orbit has been driven by Elon Musk’s SpaceX, which has launched more than 1,000 of its Starlink satellites in the past year or so. The company intends to put up a constellation of thousands more, each weighing about 550 pounds, that would beam the Internet to remote and rural places on the ground that are not served by broadband.

​Late last year, SpaceX received $886 million from the Federal Communications Commission as part of an effort to help bring Internet service to underserved communities. The awards would bring “welcome news to millions of unconnected rural Americans who for too long have been on the wrong side of the digital divide,” then-FCC Chairman Ajit Pai said at the time.

Several other companies have similar plans.

OneWeb, which recently emerged from bankruptcy, has more than 100 satellites in orbit and plans to launch hundreds more. It says it can build a satellite in a day instead of the weeks or months it takes for larger spacecraft. And they cost about $1 million each, compared with the $150 million to $400 million for a larger satellites that live in more distant orbits, and are able to endure for years.

Amazon plans to launch a constellation it calls Kuiper that would put up some 3,200 satellites. It has until 2026 launch half of those to keep its approval from the FCC.
But it does not take millions of dollars to make and launch a satellite anymore.

The Education Department is sponsoring a competition among high schools across the country to build cubesat prototypes. It recently announced five finalists whose proposed small-satellite projects would determine whether homeless encampments in California are in high-risk wildfire areas, study the different ways urban and rural areas absorb heat, and determine how a North Carolina town’s population growth affects “air quality, land use and temperature.”

At the University of Michigan, Professor Brian Gilchrist’s engineering class worked to build a small satellite that would test using the Earth’s magnetic field for propulsion. If successful, it would have allowed small satellites to orbit Earth without having to carry fuel, allowing them to stay aloft for longer periods of time. It was a novel project for the class. “None of the students involved in this project had ever built a spacecraft before,” Gilchrist said.

The cost was about $500,000 to $600,000, paid in part by the university and NASA. Parts came from industrial mail order suppliers, including a few from Amazon, Gilchrist said.
Meantime, he said, some of them are back in the lab “and now are already working on ideas for the next one.”

[End of Article]
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​Planet Labs, Inc. (formerly Cosmogia, Inc.) is an American private Earth imaging company based in San Francisco, California. Their goal is to image the entirety of the Earth daily to monitor changes and pinpoint trends.

The company designs and manufactures Triple-CubeSat miniature satellites called Doves that are then delivered into orbit as secondary payloads on other rocket launch missions.

Each Dove is equipped with a high-powered telescope and camera programmed to capture different swaths of Earth. Each Dove Earth observation satellite continuously scans Earth, sending data once it passes over a ground station, by means of a frame image sensor.

The images gathered by Doves, which can be accessed online and some of which is available under an open data access policy, provide up-to-date information relevant to climate monitoring, crop yield prediction, urban planning, and disaster response.

With acquisition of BlackBridge in July 2015, Planet Labs had 87 Dove and 5 RapidEye satellites launched into orbit In 2017, Planet launched an additional 88 Dove satellites, and Google sold its subsidiary Terra Bella and its SkySat satellite constellation to Planet Labs.

By September 2018 the company had launched nearly 300 satellites, 150 of which are active. In 2020, Planet Labs launched six additional high-resolution SkySats, SkySats 16–21, and 35 Dove satellites.

Through a deal funded by Norway’s Climate and Forests Initiative (NICFI), Planet and its partners Airbus and KSAT are providing access to high-resolution basemaps of 64 tropical countries to help combat deforestation.

Following a January 2021 launch of 48 Planet SuperDoves, the company now operates a global constellation of over 200 active satellites.

History:
​
Planet Labs was founded in 2010 as Cosmogia by former NASA scientists Chris Boshuizen, Will Marshall, and Robbie Schingler. The initial goal of the company was to make use of information gathered from space to help with life on Earth.

The group of scientists considered the problem with most satellites to be their large and clunky form, prompting them to build inexpensive and compact satellites to be manufactured in bulk, called CubeSats. The small group began building Planet's first satellite in a California garage.

Planet Labs launched two demonstration CubeSats, Dove 1 and Dove 2, in April 2013. Both Dove 1 (aboard Antares 110 rocket) and Dove 2 (aboard a Soyuz Rocket) were placed in a sun-synchronous orbit. Dove 3 and Dove 4 were launched in November 2013.

In June 2013, it announced plans for Flock-1, a constellation of 28 Earth-observing satellites.

The Flock-1 CubeSats were brought to the International Space Station in January 2014 and deployed via the NanoRacks CubeSat Deployer in mid-February. The company planned to launch a total of 131 satellites by mid-2015.

In January 2015, the firm raised $95 million in funding. As of May 2015, Planet Labs raised a total amount of $183 million in venture capital financing.

In July 2015, Planet Labs acquired BlackBridge and its RapidEye constellation.

On April 18, 2017, Google completed the sale of Terra Bella and its SkySat satellite constellation to Planet Labs. As part of the sale, Google acquired an equity stake in Planet and entered into a multi-year agreement to purchase SkySat imaging data.

On January 21, 2018, a Dove Pioneer CubeSat was part of the payload of a Rocket Lab Electron rocket, the first orbital-entry craft launched from a privately owned and operated spaceport at Mahia Peninsula in New Zealand.

In July 2018, Planet laid off somewhat less than ten percent of its workforce. In September 2018, the company had launched a total of 298 satellites, 150 of which were still active.

On December 18, 2018, Planet announced they were in the process of acquiring the St Louis company, Boundless Spatial, Inc., a geospatial data software solutions company. The portfolio of Boundless will help improve data subscription services and aid in Planet's long-term goal of increasing cooperation between the company and the U.S. government.

On 3 July 2020, it was mentioned in the news that the company had "more than 120" active satellites at the time "providing daily imaging coverage over all of the world’s landmass".

In August 2020, Planet completed its SkySat Constellation of 21 satellites by launching the final three SkySats on a SpaceX Falcon 9 rocket.

Flock satellite constellations:

Planet's PlanetScope satellite constellation is designed to observe Earth. By using several small satellites, CubeSats, the constellation produces three to five meters high resolution images of Earth. The flock collects images from latitudes that are within 52 degrees of Earth's equator. 

A large portion of the world's agricultural regions and population lie within the area imaged by the flock. Initially, the mission used the ISS (International Space Station) and different track launch vehicles to get in orbit.

Planet's Dove satellites are CubeSats that weigh 4 kilograms (8.8 lb) (1000 times lower than legacy commercial imaging satellites), 10 by 10 by 30 centimeters (3.9 in × 3.9 in × 11.8 in) in length, width and height, orbit at a height of about 400 kilometers (250 mi) and provide imagery with a resolution of 3–5 meters (9.8–16.4 ft) and envisaged environmental, humanitarian, and business applications.:
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  • Flock 2e, consisting of twenty Dove Satellites, was launched on 23 March 2016 on the Cygnus CRS OA-6 cargo mission.
  • Flock 2p, consisting of twelve Dove satellites, and Flock 3p, consisting of 88 Dove satellites, were launched from Satish Dhawan Space Centre in Sriharikota, India, by ISRO (Indian Space Research Organization) PSLV-C37 on 22 June 2016 and 15 February 2017, respectively. Flock 3p was the largest satellite fleet ever launched.
  • Flock 2k, consisting of 48 Dove satellites, launched on 14 July 2017 aboard Soyuz-2.1a.
  • Flock 3m, consisting of just four Dove satellites, was launched on 31 October 2017 on a Minotaur C rocket, along with six of Planet's SkySat satellites.
  • Flock 3p', which consists of four Dove satellites, was launched in India ISRO's PSLV-C40 mission on 12 January 2018.
  • Flock 3s, consisting of 3 satellites launched on 3 December 2018 aboard a SpaceX Falcon 9 rocket from Vandenberg Air Force Base in California.
  • Flock 3k, consisting of 12 Dove satellites, was launched on 26 December 2018 at 05:00:00 UTC. The flock was launched on a Soyuz Rocket from the Vostochny Cosmodrome in Russia into a sun-synchronous orbit.
  • Flock 4a, launched 1 April 2019, consisting of 20 satellites with improved imaging technology. The flock was delivered to 504 km sun-synchronous orbit on ISRO's PSLV-C45 rocket.
  • Flock 4p, consisting 12 SuperDoves with multiple spectral bands and other improvements was launched at 03:58 UTC on 27 November 2019 by PSLV C47 into a sun-synchronous orbit.
  • Flock 4e, consisting of 5 SuperDoves was planned to be launched into a 500 km SSO orbit onboard Electron on 4 July 2020. However, due to a failure during the second stage burn, the payloads failed to reach orbit.
  • Flock 4e’, consisting of nine SuperDoves, was successfully launched on Rocket Labs Electron Rocket on October 28, 2020.
  • Flock 4s, consisting of 48 SuperDoves, was successfully launched on SpaceX’s Transporter-1 mission. This record-breaking launch successfully deployed 143 satellites - the most ever on a single mission.

​RapidEye:
Main article: RapidEye

RapidEye was a five-satellite constellation producing 5 metres (16 ft) resolution imagery that Planet acquired from the German company BlackBridge.

The satellites were built by Surrey Satellite Technology Ltd. (SSTL) of Guildford, subcontracted by MacDonald Dettwiler (MDA) of Richmond, Canada. Each satellite was based on an evolution of the flight-proven SSTL-150 bus, measuring less than 1 cubic meter (35 cu ft) and weighing 150 kilograms (330 lb) (bus + payload) each. They were launched on 29 August 2008 on a Dnepr rocket from Baikonur cosmodrome in Kazakhstan.

Each of RapidEye's five satellites contained identical Jena-Optronik Spaceborne Scanner JSS 56 multi-spectral pushbroom sensor imagers.

The five satellites traveled on the same orbital plane (at an altitude of 630 km), and together were capable of collecting over 4 million kilometres (2.5×106 mi) of 5 metres (16 ft) resolution, 5-band color imagery every day. They collected data in the Blue (440-510 nm), Green (520-590 nm), Red (630-690 nm), Red-Edge (690-730 nm) and Near-Infrared (760-880 nm).

The RapidEye constellation was officially retired in April 2020.

SkySat:

SkySat is a constellation of sub-meter resolution Earth observation satellites that provide imagery, high-definition video and analytics services. Planet acquired the satellites with their purchase of Terra Bella (formerly Skybox Imaging), a Mountain View, California-based company founded in 2009 by Dan Berkenstock, Julian Mann, John Fenwick, and Ching-Yu Hu, from Google in 2017.

The SkySat satellites are based on the CubeSat concept, using inexpensive automotive grade electronics and fast commercially available processors, but scaled up to approximately the size of a minifridge. The satellites are approximately 80 centimeters (31 in) long, compared to approximately 30 centimeters (12 in) for a 3U CubeSat, and weigh 100 kilograms (220 lb).

The first SkySat satellite, SkySat-1, was launched on a Dnepr (rocket) from Yasny, Russia on 21 November 2013, and the second, SkySat-2, launched on a Soyuz-2/Fregat rocket from Baikonur, Kazakhstan on 8 July 2014. 

Four more SkySat units were launched on 16 September 2016, by the Vega rocket's seventh flight from Kourou, and six more SkySat satellites, along with four Dove CubeSats, were launched on a Minotaur-C rocket from Vandenberg Air Force Base on 31 October 2017.

In 2020, Planet lowered their constellation of 15 SkySats from an altitude of 500 kilometers to 450 kilometers to improved the resolution of orthorectified imagery from 80 centimeters to 50 centimeters per pixel.

On June 13, 2020, SpaceX's Falcon 9 rocket successfully launched SkySats 16, 17 and 18 along with a batch of its Starlink communications satellites.

SkySats 19, 20 and 21 were launched on August 18, 2020 on SpaceX's Falcon 9 rocket. This completed the SkySat fleet of 21 high-resolution satellites.

When launched, the SkySat constellation was orbiting at an altitude of 450 kilometres (280 mi) and has a multispectral, panchromatic, and video sensor. It has a spatial resolution of 0.9 metres in its 400–900 nm panchromatic band, making it the smallest satellite to be put in orbit capable of such high resolution imagery. The multispectral sensor collects data in blue (450–515 nm), green (515–595 nm), red (605–695 nm), and near-infrared (740–900 nm) bands, all at 2 metre resolution.

See also:







NASA had flown the Ingenuity helicopter* on Mars, in an otherworldly Wright brothers moment (Washington Post 4/10/2021)
(* -Click here for more about Ingenuity Helicopter) ​Pictured below: NASA's Ingenuity helicopter dropped on Mars' surface ahead of flight
​NASA is preparing to fly the Ingenuity helicopter on Mars, in an otherworldly ‘Wright brothers moment.’  The first flight may reach an altitude of about 10 feet, with more ambitious missions to come.

​By Christian Davenport
April 10, 2021 at 1:20 p.m. CDT (Washington Post)

They landed a car-size rover on Mars, and the brilliant, if cheeky, engineers at NASA’s Jet Propulsion Laboratory even snuck a coded message into the parachute used to slow it down for a soft landing that read: “Dare Mighty Things.”

Now comes what a JPL official dubbed a “Wright brothers moment" on Mars: the first powered flight of an aircraft on another planet.

It won’t fly far, just to the height of a basketball rim and down. But the autonomous flight of a tiny helicopter called Ingenuity would mark a first in interplanetary travel, demonstrate a new technology and pave the way for scientists and explorers to more quickly traverse the surface of the Red Planet.

Originally expected to happen as early as Sunday, the flight was postponed until no earlier than Wednesday after a problem during a test of spinning the rotor blades at full power. In a statement Saturday, NASA said, “The helicopter is safe and healthy and communicated its full telemetry set to Earth.” But it is diagnosing the problem before running another test.

The flight will be a technology demonstration add-on to the main feature of the mission — the Perseverance rover, a six-wheeled vehicle designed to explore the landscape of a crater that once held water and could yield clues about the possibility of ancient life there.

The rover is outfitted with all sorts of cameras and sensors that can zoom in on rock formations and collect data about the planet’s landscape and climate. “Reading the geological history embedded in its rocks will give scientists a richer sense of what the planet was like in its distant past,” NASA said.

Perseverance carried Ingenuity with it, a tiny offspring clinging to the under-carriage of the rover during the seven-month, 300-million-mile journey, the white knuckled landing through Mars’s atmosphere and the frigid Martian nights since.

Now it’s almost ready for its first flight. “It could be an amazing day,” Tim Canham, NASA’s Ingenuity operations lead, told reporters Friday. “We’re all nervous, but we have confidence that we put in the work and the time and we have the right people to do the job.”

Ingenuity is a sprite of a helicopter, just four pounds, with four pointy legs, two rotor blades that whirl in opposite directions at blinding speed, a solar panel and a fuselage packed with avionics designed to help it navigate the thin Martian atmosphere — another marvel to emerge from the labs at NASA’s Jet Propulsion Laboratory.
It’s no easy feat, flying a helicopter on Mars. The reduced gravity — about one-third of Earth’s — will help it take off and stay aloft. But the paucity of the Martian atmosphere, just 1 percent of the density of Earth’s, doesn’t give the blades much to chew on as they try to gain purchase for liftoff.

“That’s the equivalent of about 100,000 feet of altitude on Earth, or three times the height of Mount Everest,” said MiMi Aung, NASA’s Ingenuity project manager. “We don’t generally fly things that high."

Commercial airliners fly at about 35,000 feet above the Earth, she noted, adding: “There were some people who doubted we could generate enough lift to fly in that thin Martian atmosphere.”

The twin blades can spin incredibly fast, about 2,400 rotations per minute, and were designed to propel the drone-like Ingenuity off the ground. “Those blades are not something off the shelf,” she said. “They are really fine-tuned to maximize the lift that we can generate in such a thin atmosphere.”

If successful, Ingenuity’s flight would come nearly 120 years after the Wright brothers’ first flight of a plane above the beach in North Carolina. Nothing like Kitty Hawk, Ingenuity’s airfield is a dusty, rock-strewn, barren strip of land that is flat enough, NASA hopes, for takeoff and landing.

Designed as a test vehicle, Ingenuity is “in the long tradition of experimental aircraft that started with the Wright brothers, who were able to bring aerial mobility as a dimension for us to be able to travel here on Earth,” NASA’s Bob Balaram, the chief engineer of the Mars helicopter project, said in a news briefing last month. “In the same way, we are hoping that Ingenuity also allows us to expand and open up aerial mobility on Mars.”

As a tribute to the Wright brothers, Ingenuity has a postage-stamp-size bit of fabric from the brothers’ aircraft attached to a cable under the solar panel.

In 1903, the Wright brothers’ first flight went about 120 feet. Ingenuity’s first flight won’t go that far. Initially it plans to lift off, rise to about 10 feet, hover for some 30 seconds and come back down.

If all goes according to plan, the helicopter could make as many as five flights, each one more ambitious than the last. The second, for example, would fly slightly higher, to 16 feet, and then horizontally for a little bit before returning to the landing site.

The Perseverance rover will assist in Ingenuity’s flight, attempting to document it and relay signals back to Earth.

Ingenuity is a side benefit to the mission, a technology demonstration that could pave the way for more aircraft on Mars in the future that “could provide a supporting role as robotic scouts, surveying terrain from above,” NASA said.

“It’s a high-risk, high-reward approach that allows us to test capabilities we can improve on later, which could also advance science on future missions,” said Lori Glaze, director of NASA’s planetary science division.

[End of Article]
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Pictured below: Diagram showing the components of Ingenuity
Ingenuity is a small robotic helicopter located on Mars since February 18, 2021. It is the first aircraft on Mars and is intended to make the first powered and fully controlled atmospheric flight, from takeoff to landing, on any planet beyond Earth. 

Part of NASA's Mars 2020 mission, the small coaxial, drone rotorcraft will serve as a technology demonstrator for the potential use of flying probes on other worlds, with the potential to scout locations of interest and support the future planning of driving routes for Mars rovers.

Ingenuity, now on the Martian surface, was attached to the underside of the Perseverance rover. Its deployment was April 3, 2021, about 60 days after Perseverance's landing at the Octavia E. Butler Landing site in Jezero crater. Takeoff is planned for no sooner than April 14, 2021. 

The rover is expected to drive approximately 100 m (330 ft) away from the drone to allow it a safe "buffer zone" in which it will attempt to fly. Ingenuity is expected to fly up to five times during its 30-day test campaign scheduled early in the rover's mission. Primarily technology demonstrations, each flight is planned to fly at altitudes ranging from 3–5 m (10–16 ft) above the ground for up to 90 seconds each. 

Ingenuity, which can travel up to 50 m (160 ft) downrange and then back to the starting area, will use autonomous control during its short flights, which will be telerobotically planned and scripted by operators at the Jet Propulsion Laboratory (JPL). It will communicate directly with the Perseverance rover after each landing. Its rotor blades were successfully unlocked on April 8, 2021, days after it detached from Perseverance.

If Ingenuity works as expected, NASA could build on its design to extend the aerial component of future Mars missions. The project is led by MiMi Aung at the JPL. Other contributors include AeroVironment, Inc., the NASA  Ames Research Center, and the NASA Langley Research Center.

Ingenuity carries a piece of fabric from the wing of the 1903 Wright Flyer, the Wright Brothers' airplane, humanity's first controlled powered flight on Earth.

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Cosmology: The Origin and Evolution of the Universe Pictured below: The Many Paths of Cosmology*
* -- from above image:

Dr. Kevin Ludwick, Newsletter Editor, APS Physics

Cosmology is a vast field, enveloping many possible research pursuits. This fact is partly because cosmology is the intersection of many seemingly disparate fields of physics.

It covers a wide range of times, from the beginning of our universe to its different possible fates, and a wide range of length scales, from the chaotic Planck scale where space-time is ruled by quantum gravity to the size of the causally connected universe and beyond.

There are many research and career avenues one can take in the field of cosmology.

Image source: https://mappingignorance.org/category/science/cosmology/

Click here for rest of article
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​Cosmology (from the Greek κόσμος, kosmos "world" and -λογία, -logia "study of") is a branch of astronomy concerned with the studies of the origin and evolution of the universe, from the Big Bang to today and on into the future. It is the scientific study of the origin, evolution, and eventual fate of the universe. Physical cosmology is the scientific study of the universe's origin, its large-scale structures and dynamics, and its ultimate fate, as well as the laws of science that govern these areas.

The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff, in Cosmologia Generalis.

Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology.

Physical cosmology is studied by scientists, such as astronomers and physicists, as well as philosophers, such as metaphysicians, philosophers of physics, and philosophers of space and time. Because of this shared scope with philosophy, theories in physical cosmology may include both scientific and non-scientific propositions, and may depend upon assumptions that cannot be tested.

Cosmology differs from astronomy in that the former is concerned with the Universe as a whole while the latter deals with individual celestial objects. Modern physical cosmology is dominated by the Big Bang theory, which attempts to bring together observational astronomy and particle physics; more specifically, a standard parameterization of the Big Bang with dark matter and dark energy, known as the Lambda-CDM model.

Theoretical astrophysicist David N. Spergel has described cosmology as a "historical science" because "when we look out in space, we look back in time" due to the finite nature of the speed of light.

Disciplines:
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Physics and astrophysics have played a central role in shaping the understanding of the universe through scientific observation and experiment. Physical cosmology was shaped through both mathematics and observation in an analysis of the whole universe.

The universe is generally understood to have begun with the Big Bang, followed almost instantaneously by cosmic inflation; an expansion of space from which the universe is thought to have emerged 13.799 ± 0.021 billion years ago. Cosmogony studies the origin of the Universe, and cosmography maps the features of the Universe.

In Diderot's Encyclopédie, cosmology is broken down into uranology (the science of the heavens), aerology (the science of the air), geology (the science of the continents), and hydrology (the science of waters).

Metaphysical cosmology has also been described as the placing of humans in the universe in relationship to all other entities. This is exemplified by Marcus Aurelius's observation that a man's place in that relationship: "He who does not know what the world is does not know where he is, and he who does not know for what purpose the world exists, does not know who he is, nor what the world is."

Discoveries:
Main article: List of discoveries in astronomy and cosmology

Physical cosmology:
Main article: Physical cosmology

Physical cosmology is the branch of physics and astrophysics that deals with the study of the physical origins and evolution of the Universe. It also includes the study of the nature of the Universe on a large scale. In its earliest form, it was what is now known as "celestial mechanics", the study of the heavens.

Greek philosophers Aristarchus of Samos, Aristotle, and Ptolemy proposed different cosmological theories. The geocentric Ptolemaic system was the prevailing theory until the 16th century when Nicolaus Copernicus, and subsequently Johannes Kepler and Galileo Galilei, proposed a heliocentric system. This is one of the most famous examples of epistemological rupture in physical cosmology.

Isaac Newton's Principia Mathematica, published in 1687, was the first description of the law of universal gravitation. It provided a physical mechanism for Kepler's laws and also allowed the anomalies in previous systems, caused by gravitational interaction between the planets, to be resolved. A fundamental difference between Newton's cosmology and those preceding it was the Copernican principle—that the bodies on earth obey the same physical laws as all the celestial bodies. This was a crucial philosophical advance in physical cosmology.

Modern scientific cosmology is usually considered to have begun in 1917 with Albert Einstein's publication of his final modification of general relativity in the paper "Cosmological Considerations of the General Theory of Relativity" (although this paper was not widely available outside of Germany until the end of World War I).

General relativity prompted cosmogonists such as Willem de Sitter, Karl Schwarzschild, and Arthur Eddington to explore its astronomical ramifications, which enhanced the ability of astronomers to study very distant objects.

Physicists began changing the assumption that the Universe was static and unchanging. In 1922 Alexander Friedmann introduced the idea of an expanding universe that contained moving matter.

Around the same time (1917 to 1922) the Great Debate took place, with early cosmologists such as Heber Curtis and Ernst Öpik determining that some nebulae seen in telescopes were separate galaxies far distant from our own.

​In parallel to this dynamic approach to cosmology, one long-standing debate about the structure of the cosmos was coming to a climax. Mount Wilson astronomer Harlow Shapley championed the model of a cosmos made up of the Milky Way star system only; while Heber D. Curtis argued for the idea that spiral nebulae were star systems in their own right as island universes.

This difference of ideas came to a climax with the organization of the Great Debate on 26 April 1920 at the meeting of the U.S. National Academy of Sciences in Washington, D.C. The debate was resolved when Edwin Hubble detected Cepheid Variables in the Andromeda Galaxy in 1923 and 1924. Their distance established spiral nebulae well beyond the edge of the Milky Way.

Subsequent modelling of the universe explored the possibility that the cosmological constant, introduced by Einstein in his 1917 paper, may result in an expanding universe, depending on its value.

Thus the Big Bang model was proposed by the Belgian priest Georges Lemaître in 1927 which was subsequently corroborated by Edwin Hubble's discovery of the redshift in 1929 and later by the discovery of the cosmic microwave background radiation by Arno Penzias and Robert Woodrow Wilson in 1964. These findings were a first step to rule out some of many alternative cosmologies.

Since around 1990, several dramatic advances in observational cosmology have transformed cosmology from a largely speculative science into a predictive science with precise agreement between theory and observation.

These advances include observations of the microwave background from the COBE, WMAP and Planck satellites, large new galaxy redshift surveys including 2dfGRS and SDSS, and observations of distant supernovae and gravitational lensing. These observations matched the predictions of the cosmic inflation theory, a modified Big Bang theory, and the specific version known as the Lambda-CDM model. This has led many to refer to modern times as the "golden age of cosmology".

On 17 March 2014, astronomers at the Harvard-Smithsonian Center for Astrophysics announced the detection of gravitational waves, providing strong evidence for inflation and the Big Bang. However, on 19 June 2014, lowered confidence in confirming the cosmic inflation findings was reported.

On 1 December 2014, at the Planck 2014 meeting in Ferrara, Italy, astronomers reported that the universe is 13.8 billion years old and is composed of 4.9% atomic matter, 26.6% dark matter and 68.5% dark energy.

Religious or mythological cosmology:
See also: Religious cosmology

Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation and eschatology.

Philosophical cosmology:
See also: Cosmology (philosophy)

Cosmology deals with the world as the totality of space, time and all phenomena. Historically, it has had quite a broad scope, and in many cases was founded in religion.

In modern use metaphysical cosmology addresses questions about the Universe which are beyond the scope of science. It is distinguished from religious cosmology in that it approaches these questions using philosophical methods like dialectics.

Modern metaphysical cosmology tries to address questions such as:
  • What is the origin of the Universe? What is its first cause? Is its existence necessary? (see monism, pantheism, emanationism and creationism)
  • What are the ultimate material components of the Universe? (see mechanism, dynamism, hylomorphism, atomism)
  • What is the ultimate reason for the existence of the Universe? Does the cosmos have a purpose? (see teleology)
  • Does the existence of consciousness have a purpose? How do we know what we know about the totality of the cosmos? Does cosmological reasoning reveal metaphysical truths? (see epistemology)

Click on any of the following blue hyperlinks for more about Cosmology:​






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The Big Bang Theory Pictured: As illustrated in the Big Bang model, the universe expanded from an extremely dense and hot state and continues to expand.
​The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution.

The model accounts for the fact that the universe expanded from a very high density and high temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure and Hubble's Law.

If the known laws of physics are extrapolated beyond where they have been verified, there is a singularity. Some estimates place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies.

Since Georges Lemaître first noted, in 1927, that an expanding universe might be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion.

While the scientific community was once divided between supporters of two different expanding universe theories, the Big Bang and the Steady State theory, accumulated empirical evidence provides strong support for the former. In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart; this is important observational evidence consistent with the hypothesis of an expanding universe.

In 1965, the cosmic microwave background radiation was discovered, which was crucial evidence in favor of the Big Bang model, since that theory predicted the existence of background radiation throughout the universe before it was discovered.

More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to dark energy's existence. 

The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature.

Overview:
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American astronomer Edwin Hubble observed that the distances to faraway galaxies were strongly correlated with their redshifts. This was interpreted to mean that all distant galaxies and clusters are receding away from our vantage point with an apparent velocity proportional to their distance: that is, the farther they are, the faster they move away from us, regardless of direction. 

Assuming the Copernican principle (that the Earth is not the center of the universe), the only remaining interpretation is that all observable regions of the universe are receding from all others. Since we know that the distance between galaxies increases today, it must mean that in the past galaxies were closer together. The continuous expansion of the universe implies that the universe was denser and hotter in the past.

Large particle accelerators can replicate the conditions that prevailed after the early moments of the universe, resulting in confirmation and refinement of the details of the Big Bang model. However, these accelerators can only probe so far into high energy regimes. Consequently, the state of the universe in the earliest instants of the Big Bang expansion is still poorly understood and an area of open investigation and speculation.

The first subatomic particles to be formed included protons, neutrons, and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed. The majority of atoms produced by the Big Bang were hydrogen, along with helium and traces of lithium. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies, and the heavier elements were synthesized either within stars or during supernovae.

The Big Bang theory offers a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the CMB, large scale structure, and Hubble's Law.

The framework for the Big Bang model relies on Albert Einstein's theory of general relativity and on simplifying assumptions such as homogeneity and isotropy of space. The governing equations were formulated by Alexander Friedmann, and similar solutions were worked on by Willem de Sitter.

Since then, astrophysicists have incorporated observational and theoretical additions into the Big Bang model, and its parametrization as the Lambda-CDM model serves as the framework for current investigations of theoretical cosmology. The Lambda-CDM model is the current "standard model" of Big Bang cosmology, consensus is that it is the simplest model that can account for the various measurements and observations relevant to cosmology.
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​Our UniversePictured below: NASA's James Webb Telescope Captures Extreme View of Galaxies Merging - CNET​
The Universe is all of time and space and its contents. It includes planets, moons, minor planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. The observable universe is about 28 billion parsecs (91 billion light-years) in diameter. The size of the entire Universe is unknown, but there are many hypotheses about the composition and evolution of the Universe.

The earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing the Earth at the center of the Universe. 

Over the centuries, more precise astronomical observations led Nicolaus Copernicus (1473–1543) to develop the heliocentric model with the Sun at the center of the Solar System.

In developing the law of universal gravitation, Sir Isaac Newton (1643–1727) built upon Copernicus's work as well as observations by Tycho Brahe (1546–1601) and Johannes Kepler's (1571–1630) laws of planetary motion.

Further observational improvements led to the realization that our Solar System is located in the Milky Way galaxy (See next topic), and is one of many solar systems and galaxies. It is assumed that galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center.

Discoveries in the early 20th century have suggested that the Universe had a beginning and that it is expanding at an increasing rate. The majority of mass in the Universe appears to exist in an unknown form called dark matter.

The Big Bang theory (see above), the prevailing cosmological model describing the development of the Universe, states that space and time were created in the Big Bang and were given a fixed amount of energy and matter that becomes less dense as space expands.

After the initial expansion, the Universe cooled, allowing the first subatomic particles to form and then simple atoms. Giant clouds later merged through gravity to form stars.

Assuming that the standard model of the Big Bang theory is correct, the age of the Universe is measured to be 13.799±0.021 billion years.

There are many competing hypotheses about the ultimate fate of the Universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will ever be accessible.

Some physicists have suggested various multiverse hypotheses, in which the Universe might be one among many universes that likewise exist.


Definition:

​The physical universe is defined as all of space and time (collectively referred to as spacetime) and their contents. Such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, and therefore planets, moons, stars, galaxies, and the contents of intergalactic space. The universe also includes the physical laws that influence energy and matter, such as conservation laws, classical mechanics, and relativity.

The universe is often defined as "the totality of existence", or everything that exists, everything that has existed, and everything that will exist. In fact, some philosophers and scientists support the inclusion of ideas and abstract concepts—such as mathematics and logic—in the definition of the universe. The word universe may also refer to concepts such as the cosmos, the world, and nature.


Etymology:

The word universe derives from the Old French word univers, which in turn derives from the Latin word universum. The Latin word was used by Cicero and later Latin authors in many of the same senses as the modern English word is used.

Synonyms:

A term for universe among the ancient Greek philosophers from Pythagoras onwards was τὸ πᾶν (tò pân) 'the all', defined as all matter and all space, and τὸ ὅλον (tò hólon) 'all things', which did not necessarily include the void. Another synonym was ὁ κόσμος (ho kósmos) meaning 'the world, the cosmos'. 

Synonyms are also found in Latin authors (totum, mundus, natura) and survive in modern languages, e.g., the German words Das All, Weltall, and Natur for universe. The same synonyms are found in English, such as everything (as in the theory of everything), the cosmos (as in cosmology), the world (as in the many-worlds interpretation), and nature (as in natural laws or natural philosophy).


Chronology and the Big Bang:
Main articles: Big Bang and Chronology of the universe

​The prevailing model for the evolution of the universe is the Big Bang theory. The Big Bang model states that the earliest state of the universe was an extremely hot and dense one, and that the universe subsequently expanded and cooled. The model is based on general relativity and on simplifying assumptions such as the homogeneity and isotropy of space.

A version of the model with a cosmological constant (Lambda) and cold dark matter, known as the Lambda-CDM model, is the simplest model that provides a reasonably good account of various observations about the universe.

The Big Bang model accounts for observations such as the correlation of distance and redshift of galaxies, the ratio of the number of hydrogen to helium atoms, and the microwave radiation background. See below illustration entitled "Nature Timeline:"
​The initial hot, dense state is called the Planck epoch, a brief period extending from time zero to one Planck time unit of approximately 10−43 seconds.

During the Planck epoch, all types of matter and all types of energy were concentrated into a dense state, and gravity—currently the weakest by far of the four known forces—is believed to have been as strong as the other fundamental forces, and all the forces may have been unified.

The physics controlling this very early period (including quantum gravity in the Planck epoch) is not understood, so we cannot say what, if anything, happened before time zero.

Since the Planck epoch, space has been expanding to its present scale, with a very short but intense period of cosmic inflation speculated to have occurred within the first 10−32 seconds. 

This was a kind of expansion different from those we can see around us today. Objects in space did not physically move; instead the metric that defines space itself changed. Although objects in spacetime cannot move faster than the speed of light, this limitation does not apply to the metric governing spacetime itself.

This initial period of inflation would explain why space appears to be very flat, and much larger than light could travel since the start of the universe.

Within the first fraction of a second of the universe's existence, the four fundamental forces had separated. As the universe continued to cool down from its inconceivably hot state, various types of subatomic particles were able to form in short periods of time known as the quark epoch, the hadron epoch, and the lepton epoch. Together, these epochs encompassed less than 10 seconds of time following the Big Bang.

These elementary particles associated stably into ever larger combinations, including stable protons and neutrons, which then formed more complex atomic nuclei through nuclear fusion. This process, known as Big Bang nucleosynthesis, only lasted for about 17 minutes and ended about 20 minutes after the Big Bang, so only the fastest and simplest reactions occurred. About 25% of the protons and all the neutrons in the universe, by mass, were converted to helium, with small amounts of deuterium (a form of hydrogen) and traces of lithium.

Any other element was only formed in very tiny quantities. The other 75% of the protons remained unaffected, as hydrogen nuclei. 

After nucleosynthesis ended, the universe entered a period known as the photon epoch. During this period, the universe was still far too hot for matter to form neutral atoms, so it contained a hot, dense, foggy plasma of negatively charged electrons, neutral neutrinos and positive nuclei.

After about 377,000 years, the universe had cooled enough that electrons and nuclei could form the first stable atoms. This is known as recombination for historical reasons; in fact electrons and nuclei were combining for the first time.

Unlike plasma, neutral atoms are transparent to many wavelengths of light, so for the first time the universe also became transparent. The photons released ("decoupled") when these atoms formed can still be seen today; they form the cosmic microwave background (CMB).

As the universe expands, the energy density of electromagnetic radiation decreases more quickly than does that of matter because the energy of a photon decreases with its wavelength. At around 47,000 years, the energy density of matter became larger than that of photons and neutrinos, and began to dominate the large scale behavior of the universe. This marked the end of the radiation-dominated era and the start of the matter-dominated era.

In the earliest stages of the universe, tiny fluctuations within the universe's density led to concentrations of dark matter gradually forming. Ordinary matter, attracted to these by gravity, formed large gas clouds and eventually, stars and galaxies, where the dark matter was most dense, and voids where it was least dense.

After around 100–300 million years,  the first stars formed, known as Population III stars. These were probably very massive, luminous, non metallic and short-lived. They were responsible for the gradual reionization of the universe between about 200–500 million years and 1 billion years, and also for seeding the universe with elements heavier than helium, through stellar nucleosynthesis. 

The universe also contains a mysterious energy—possibly a scalar field—called dark energy, the density of which does not change over time. After about 9.8 billion years, the universe had expanded sufficiently so that the density of matter was less than the density of dark energy, marking the beginning of the present dark-energy-dominated era. In this era, the expansion of the universe is accelerating due to dark energy.


Physical properties:
Main articles:  ​
Of the four fundamental interactions, gravitation is the dominant at astronomical length scales. Gravity's effects are cumulative; by contrast, the effects of positive and negative charges tend to cancel one another, making electromagnetism relatively insignificant on astronomical length scales. The remaining two interactions, the weak and strong nuclear forces, decline very rapidly with distance; their effects are confined mainly to sub-atomic length scales.

The universe appears to have much more matter than antimatter, an asymmetry possibly related to the CP violation. This imbalance between matter and antimatter is partially responsible for the existence of all matter existing today, since matter and antimatter, if equally produced at the Big Bang, would have completely annihilated each other and left only photons as a result of their interaction.

The universe also appears to have neither net momentum nor angular momentum, which follows accepted physical laws if the universe is finite. These laws are Gauss's law and the non-divergence of the stress–energy–momentum pseudotensor.

Size and regions:
See also: Observational cosmology

According to the general theory of relativity, far regions of space may never interact with ours even in the lifetime of the universe due to the finite speed of light and the ongoing expansion of space. For example, radio messages sent from Earth may never reach some regions of space, even if the universe were to exist forever: space may expand faster than light can traverse it.

The spatial region that can be observed with telescopes is called the observable universe, which depends on the location of the observer. The proper distance—the distance as would be measured at a specific time, including the present—between Earth and the edge of the observable universe is 46 billion light-years (14 billion parsecs), making the diameter of the observable universe about 93 billion light-years (28 billion parsecs).

The distance the light from the edge of the observable universe has travelled is very close to the age of the universe times the speed of light, 13.8 billion light-years (4.2×109 pc), but this does not represent the distance at any given time because the edge of the observable universe and the Earth have since moved further apart. 

For comparison, the diameter of a typical galaxy is 30,000 light-years (9,198 parsecs), and the typical distance between two neighboring galaxies is 3 million light-years (919.8 kiloparsecs). 

As an example, the Milky Way is roughly 100,000–180,000 light-years in diameter, and the nearest sister galaxy to the Milky Way, the Andromeda Galaxy, is located roughly 2.5 million light-years away.

Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the universe in its totality is finite or infinite. Estimates suggest that the whole universe, if finite, must be more than 250 times larger than a Hubble sphere. 

Some disputed estimates for the total size of the universe, if finite, reach as high as 101010122 megaparsecs, as implied by a suggested resolution of the No-Boundary Proposal.

Age and expansion:
Main articles: 
Assuming that the Lambda-CDM model is correct, the measurements of the parameters using a variety of techniques by numerous experiments yield a best value of the age of the universe at 13.799 ± 0.021 billion years, as of 2015.

Over time, the universe and its contents have evolved; for example, the relative population of quasars and galaxies has changed and space itself has expanded. Due to this expansion, scientists on Earth can observe the light from a galaxy 30 billion light-years away even though that light has traveled for only 13 billion years; the very space between them has expanded.

This expansion is consistent with the observation that the light from distant galaxies has been redshifted; the photons emitted have been stretched to longer wavelengths and lower frequency during their journey. Analyses of Type Ia supernovae indicate that the spatial expansion is accelerating.

The more matter there is in the universe, the stronger the mutual gravitational pull of the matter. If the universe were too dense then it would re-collapse into a gravitational singularity. However, if the universe contained too little matter then the self-gravity would be too weak for astronomical structures, like galaxies or planets, to form.

Since the Big Bang, the universe has expanded monotonically. Perhaps unsurprisingly, our universe has just the right mass–energy density, equivalent to about 5 protons per cubic metre, which has allowed it to expand for the last 13.8 billion years, giving time to form the universe as observed today.

There are dynamical forces acting on the particles in the universe which affect the expansion rate. Before 1998, it was expected that the expansion rate would be decreasing as time went on due to the influence of gravitational interactions in the universe; and thus there is an additional observable quantity in the universe called the deceleration parameter, which most cosmologists expected to be positive and related to the matter density of the universe.

In 1998, the deceleration parameter was measured by two different groups to be negative, approximately −0.55, which technically implies that the second derivative of the cosmic scale factor �¨ has been positive in the last 5–6 billion years.

Spacetime:
Main articles:  See also: Lorentz transformation

Modern physics regards events as being organized into spacetime. This idea originated with the special theory of relativity, which predicts that if one observer sees two events happening in different places at the same time, a second observer who is moving relative to the first will be see those events happening at different times.  

The two observers will disagree on the time between the events, and they will disagree about the distance separating the events, but they will agree on the speed of light, and they will measure the same value for the combination.  

The square root of the absolute value of this quantity is called the interval between the two events. The interval expresses how widely separated events are, not just in space or in time, but in the combined setting of spacetime.

The special theory of relativity cannot account for gravity. Its successor, the general theory of relativity, explains gravity by recognizing that spacetime is not fixed but instead dynamical.

In general relativity, gravitational force is reimagined as curvature of spacetime. A curved path like an orbit is not the result of a force deflecting a body from an ideal straight-line path, but rather the body's attempt to fall freely through a background that is itself curved by the presence of other masses.

A remark by John Archibald Wheeler that has become proverbial among physicists summarizes the theory: "Spacetime tells matter how to move; matter tells spacetime how to curve." (The Newtonian theory of gravity is a good approximation to the predictions of general relativity when gravitational effects are weak and objects are moving slowly compared to the speed of light.

The relation between matter distribution and spacetime curvature is given by the Einstein field equations, which require tensor calculus to express. The solutions to these equations include not only the spacetime of special relativity, Minkowski spacetime, but also Schwarzschild spacetimes, which describe black holes; FLRW spacetime, which describes an expanding universe; and more.

The universe appears to be a smooth spacetime continuum consisting of three spatial dimensions and one temporal (time) dimension. Therefore, an event in the spacetime of the physical universe can therefore be identified by a set of four coordinates: (x, y, z, t).

On average, space is observed to be very nearly flat (with a curvature close to zero), meaning that Euclidean geometry is empirically true with high accuracy throughout most of the Universe. Spacetime also appears to have a simply connected topology, in analogy with a sphere, at least on the length scale of the observable universe.

However, present observations cannot exclude the possibilities that the universe has more dimensions (which is postulated by theories such as the string theory) and that its spacetime may have a multiply connected global topology, in analogy with the cylindrical or toroidal topologies of two-dimensional spaces.

​Shape:
Main article: Shape of the universe

​General relativity describes how spacetime is curved and bent by mass and energy (gravity). The topology or geometry of the universe includes both local geometry in the observable universe and global geometry. Cosmologists often work with a given space-like slice of spacetime called the comoving coordinates.

The section of spacetime which can be observed is the backward light cone, which delimits the cosmological horizon. The cosmological horizon (also called the particle horizon or the light horizon) is the maximum distance from which particles can have traveled to the observer in the age of the universe.

This horizon represents the boundary between the observable and the unobservable regions of the universe. The existence, properties, and significance of a cosmological horizon depend on the particular cosmological model.

An important parameter determining the future evolution of the universe theory is the density parameter, Omega (Ω), defined as the average matter density of the universe divided by a critical value of that density. This selects one of three possible geometries depending on whether Ω is equal to, less than, or greater than 1. These are called, respectively, the flat, open and closed universes.

Observations, including the Cosmic Background Explorer (COBE), Wilkinson Microwave Anisotropy Probe (WMAP), and Planck maps of the CMB, suggest that the universe is infinite in extent with a finite age, as described by the Friedmann–Lemaître–Robertson–Walker (FLRW) models. These FLRW models thus support inflationary models and the standard model of cosmology, describing a flat, homogeneous universe presently dominated by dark matter and dark energy.

Support of life:
Main article: Fine-tuned universe

The fine-tuned universe hypothesis is the proposition that the conditions that allow the existence of observable life in the universe can only occur when certain universal fundamental physical constants lie within a very narrow range of values.

According to this hypothesis, if any of several fundamental constants were only slightly different, the universe would have been unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is understood.

Whether this is true, and whether that question is even logically meaningful to ask, are subjects of much debate. The proposition is discussed among philosophers, scientists, theologians, and proponents of creationism.


Composition:
See also: 
The universe is composed almost completely of dark energy, dark matter, and ordinary matter. Other contents are electromagnetic radiation (estimated to constitute from 0.005% to close to 0.01% of the total mass–energy of the universe) and antimatter.

The proportions of all types of matter and energy have changed over the history of the universe. The total amount of electromagnetic radiation generated within the universe has decreased by 1/2 in the past 2 billion years. 

Today, ordinary matter, which includes atoms, stars, galaxies, and life, accounts for only 4.9% of the contents of the Universe. The present overall density of this type of matter is very low, roughly 4.5 × 10−31 grams per cubic centimetre, corresponding to a density of the order of only one proton for every four cubic metres of volume. 

The nature of both dark energy and dark matter is unknown. Dark matter, a mysterious form of matter that has not yet been identified, accounts for 26.8% of the cosmic contents. Dark energy, which is the energy of empty space and is causing the expansion of the universe to accelerate, accounts for the remaining 68.3% of the contents.

Matter, dark matter, and dark energy are distributed homogeneously throughout the universe over length scales longer than 300 million light-years or so. 

However, over shorter length-scales:
  • matter tends to clump hierarchically;
  • many atoms are condensed into stars,
  • most stars into galaxies,
  • most galaxies into clusters, superclusters and, finally, large-scale galactic filaments. The observable universe contains as many as 200 billion galaxies 
  • and, overall, as many as an estimated 1×1024 stars (more stars than all the grains of sand on planet Earth). 

Typical galaxies range from dwarfs with as few as ten million stars up to giants with one trillion (1012) stars. Between the larger structures are voids, which are typically 10–150 Mpc (33 million–490 million ly) in diameter.

The Milky Way is in the Local Group of galaxies, which in turn is in the Laniakea Supercluster. This supercluster spans over 500 million light-years, while the Local Group spans over 10 million light-years. The Universe also has vast regions of relative emptiness; the largest known void measures 1.8 billion ly (550 Mpc) across.

​Dark energy:
Main article: Dark energy

An explanation for why the expansion of the universe is accelerating remains elusive. It is often attributed to "dark energy", an unknown form of energy that is hypothesized to permeate space. On a mass–energy equivalence basis, the density of dark energy  is much less than the density of ordinary matter or dark matter within galaxies.

However, in the present dark-energy era, it dominates the mass–energy of the universe because it is uniform across space.

Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and scalar fields such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space.

Contributions from scalar fields that are constant in space are usually also included in the cosmological constant. The cosmological constant can be formulated to be equivalent to vacuum energy. Scalar fields having only a slight amount of spatial inhomogeneity would be difficult to distinguish from a cosmological constant.

Dark matter:
Main article: Dark matter

Dark matter is a hypothetical kind of matter that is invisible to the entire electromagnetic spectrum, but which accounts for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.

Other than neutrinos, a form of hot dark matter, dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics. Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. Dark matter is estimated to constitute 26.8% of the total mass–energy and 84.5% of the total matter in the universe.

Ordinary matter:
Main article: Matter

The remaining 4.9% of the mass–energy of the universe is ordinary matter, that is, atoms, ions, electrons and the objects they form. This matter includes stars, which produce nearly all of the light we see from galaxies, as well as interstellar gas in the interstellar and intergalactic media, planets, and all the objects from everyday life that we can bump into, touch or squeeze. 

As a matter of fact, the great majority of ordinary matter in the universe is unseen, since visible stars and gas inside galaxies and clusters account for less than 10 per cent of the ordinary matter contribution to the mass–energy density of the universe.

Ordinary matter commonly exists in four states (or phases): 
However, advances in experimental techniques have revealed other previously theoretical phases, such as Bose–Einstein condensates and fermionic condensates.

Ordinary matter is composed of two types of elementary particles: quarks and leptons. For example, the proton is formed of two up quarks and one down quark; the neutron is formed of two down quarks and one up quark; and the electron is a kind of lepton. An atom consists of an atomic nucleus, made up of protons and neutrons, and electrons that orbit the nucleus.  

Because most of the mass of an atom is concentrated in its nucleus, which is made up of baryons, astronomers often use the term baryonic matter to describe ordinary matter, although a small fraction of this "baryonic matter" is electrons.

Soon after the Big Bang, primordial protons and neutrons formed from the quark–gluon plasma of the early universe as it cooled below two trillion degrees. A few minutes later, in a process known as Big Bang nucleosynthesis, nuclei formed from the primordial protons and neutrons.

This nucleosynthesis formed lighter elements, those with small atomic numbers up to lithium and beryllium, but the abundance of heavier elements dropped off sharply with increasing atomic number. Some boron may have been formed at this time, but the next heavier element, carbon, was not formed in significant amounts.

Big Bang nucleosynthesis shut down after about 20 minutes due to the rapid drop in temperature and density of the expanding universe. Subsequent formation of heavier elements resulted from stellar nucleosynthesis and supernova nucleosynthesis.

Particles:
​Main article: Particle physics

Ordinary matter and the forces that act on matter can be described in terms of elementary particles. These particles are sometimes described as being fundamental, since they have an unknown substructure, and it is unknown whether or not they are composed of smaller and even more fundamental particles. 

All elementary particles are currently best explained by quantum mechanics and exhibit wave–particle duality: their behavior has both particle-like and wave-like aspects, with different features dominating under different circumstances. 

Of central importance is the Standard Model, a theory that is concerned with electromagnetic interactions and the weak and strong nuclear interactions. The Standard Model is supported by the experimental confirmation of the existence of particles that compose matter: quarks and leptons, and their corresponding "antimatter" duals, as well as the force particles that mediate interactions: the photon, the W and Z bosons, and the gluon. 

The Standard Model predicted the existence of the recently discovered Higgs boson, a particle that is a manifestation of a field within the universe that can endow particles with mass. 

Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a "theory of almost everything". The Standard Model does not, however, accommodate gravity. A true force–particle "theory of everything" has not been attained.

Hadrons:
Main article: Hadron

A hadron is a composite particle made of quarks held together by the strong force. Hadrons are categorized into two families: baryons (such as protons and neutrons) made of three quarks, and mesons (such as pions) made of one quark and one antiquark. Of the hadrons, protons are stable, and neutrons bound within atomic nuclei are stable.

Other hadrons are unstable under ordinary conditions and are thus insignificant constituents of the modern universe.  From approximately 10−6 seconds after the Big Bang, during a period known as the hadron epoch, the temperature of the universe had fallen sufficiently to allow quarks to bind together into hadrons, and the mass of the universe was dominated by hadrons.

Initially, the temperature was high enough to allow the formation of hadron–anti-hadron pairs, which kept matter and antimatter in thermal equilibrium. However, as the temperature of the universe continued to fall, hadron–anti-hadron pairs were no longer produced. Most of the hadrons and anti-hadrons were then eliminated in particle–antiparticle annihilation reactions, leaving a small residual of hadrons by the time the universe was about one second old. 

Leptons:
Main article: Lepton

A lepton is an elementary, half-integer spin particle that does not undergo strong interactions but is subject to the Pauli exclusion principle; no two leptons of the same species can be in exactly the same state at the same time. 

Two main classes of leptons exist: 
  1. charged leptons (also known as the electron-like leptons),
  2. and neutral leptons (better known as neutrinos).

Electrons are stable and the most common charged lepton in the universe, whereas muons and taus are unstable particles that quickly decay after being produced in high energy collisions, such as those involving cosmic rays or carried out in particle accelerators.

Charged leptons can combine with other particles to form various composite particles such as atoms and positronium. The electron governs nearly all of chemistry, as it is found in atoms and is directly tied to all chemical properties.

Neutrinos rarely interact with anything, and are consequently rarely observed. Neutrinos stream throughout the universe but rarely interact with normal matter.

The lepton epoch was the period in the evolution of the early universe in which the leptons dominated the mass of the universe. It started roughly 1 second after the Big Bang, after the majority of hadrons and anti-hadrons annihilated each other at the end of the hadron epoch.

During the lepton epoch the temperature of the universe was still high enough to create lepton–anti-lepton pairs, so leptons and anti-leptons were in thermal equilibrium.

​Approximately 10 seconds after the Big Bang, the temperature of the universe had fallen to the point where lepton–anti-lepton pairs were no longer created. Most leptons and anti-leptons were then eliminated in annihilation reactions, leaving a small residue of leptons. The mass of the universe was then dominated by photons as it entered the following photon epoch.

Photons:
A photon is the quantum of light and all other forms of electromagnetic radiation. It is the carrier for the electromagnetic force. The effects of this force are easily observable at the microscopic and at the macroscopic level because the photon has zero rest mass; this allows long distance interactions. 

The photon epoch started after most leptons and anti-leptons were annihilated at the end of the lepton epoch, about 10 seconds after the Big Bang. Atomic nuclei were created in the process of nucleosynthesis which occurred during the first few minutes of the photon epoch.

For the remainder of the photon epoch the universe contained a hot dense plasma of nuclei, electrons and photons. About 380,000 years after the Big Bang, the temperature of the Universe fell to the point where nuclei could combine with electrons to create neutral atoms.

​As a result, photons no longer interacted frequently with matter and the universe became transparent. The highly redshifted photons from this period form the cosmic microwave background. Tiny variations in temperature and density detectable in the CMB were the early "seeds" from which all subsequent structure formation took place. ​

Below: Graphical timeline of the Big Bang:
Main article: Chronology of the universe

This timeline of the Big Bang shows a sequence of events as currently theorized by scientists.

It is a logarithmic scale that shows 10⋅log10 second instead of second. For example, one microsecond is 10⋅log10⁡0.000001=10⋅(−6)=−60. To convert −30 read on the scale to second calculate 10−3010=10−3=0.001 second = one millisecond. On a logarithmic time scale a step lasts ten times longer than the previous step.
Cosmological models:

Model of the universe based on general relativity
Main article: Solutions of the Einstein field equations

See also: Big Bang and Ultimate fate of the universe

General relativity is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. It is the basis of current cosmological models of the universe.

General relativity generalizes special relativity and Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present.

The relation is specified by the Einstein field equations, a system of partial differential equations. In general relativity, the distribution of matter and energy determines the geometry of spacetime, which in turn describes the acceleration of matter.

Therefore, solutions of the Einstein field equations describe the evolution of the universe. Combined with measurements of the amount, type, and distribution of matter in the universe, the equations of general relativity describe the evolution of the universe over time.

With the assumption of the cosmological principle that the universe is homogeneous and isotropic everywhere, a specific solution of the field equations that describes the universe is the metric tensor called the Friedmann–Lemaître–Robertson–Walker metric,
��2=−�2��2+�(�)2(��21−��2+�2��2+�2sin2⁡���2)where (r, θ, φ) correspond to a spherical coordinate system.

This metric has only two undetermined parameters. An overall dimensionless length scale factor R describes the size scale of the universe as a function of time (an increase in R is the expansion of the universe), and a curvature index k describes the geometry.

The index k is defined so that it can take only one of three values: 0, corresponding to flat Euclidean geometry; 1, corresponding to a space of positive curvature; or −1, corresponding to a space of positive or negative curvature. 

The value of R as a function of time t depends upon k and the cosmological constant. 

The cosmological constant represents the energy density of the vacuum of space and could be related to dark energy. 

The equation describing how R varies with time is known as the Friedmann equation after its inventor, Alexander Friedmann.

The solutions for R(t) depend on k and Λ, but some qualitative features of such solutions are general. First and most importantly, the length scale R of the universe can remain constant only if the universe is perfectly isotropic with positive curvature (k=1) and has one precise value of density everywhere, as first noted by Albert Einstein. 

However, this equilibrium is unstable: because the universe is inhomogeneous on smaller scales, R must change over time. When R changes, all the spatial distances in the universe change in tandem; there is an overall expansion or contraction of space itself.

This accounts for the observation that galaxies appear to be flying apart; the space between them is stretching. The stretching of space also accounts for the apparent paradox that two galaxies can be 40 billion light-years apart, although they started from the same point 13.8 billion years ago and never moved faster than the speed of light.

Second, all solutions suggest that there was a gravitational singularity in the past, when R went to zero and matter and energy were infinitely dense. It may seem that this conclusion is uncertain because it is based on the questionable assumptions of perfect homogeneity and isotropy (the cosmological principle) and that only the gravitational interaction is significant.

However, the Penrose–Hawking singularity theorems show that a singularity should exist for very general conditions. Hence, according to Einstein's field equations, R grew rapidly from an unimaginably hot, dense state that existed immediately following this singularity (when R had a small, finite value); this is the essence of the Big Bang model of the universe.

Understanding the singularity of the Big Bang likely requires a quantum theory of gravity, which has not yet been formulated.

Third, the curvature index k determines the sign of the mean spatial curvature of spacetime averaged over sufficiently large length scales (greater than about a billion light-years). If k=1, the curvature is positive and the universe has a finite volume. 

A universe with positive curvature is often visualized as a three-dimensional sphere embedded in a four-dimensional space. Conversely, if k is zero or negative, the universe has an infinite volume. It may seem counter-intuitive that an infinite and yet infinitely dense universe could be created in a single instant when R = 0, but exactly that is predicted mathematically when k does not equal 1.

By analogy, an infinite plane has zero curvature but infinite area, whereas an infinite cylinder is finite in one direction and a torus is finite in both. A toroidal universe could behave like a normal universe with periodic boundary conditions.

The ultimate fate of the universe is still unknown because it depends critically on the curvature index k and the cosmological constant Λ. If the universe were sufficiently dense, k would equal +1, meaning that its average curvature throughout is positive and the universe will eventually recollapse in a Big Crunch, possibly starting a new universe in a Big Bounce.

Conversely, if the universe were insufficiently dense, k would equal 0 or −1 and the universe would expand forever, cooling off and eventually reaching the Big Freeze and the heat death of the universe. Modern data suggests that the rate of expansion of the universe is not decreasing, as originally expected, but increasing; if this continues indefinitely, the universe may eventually reach a Big Rip.

Observationally, the universe appears to be flat (k = 0), with an overall density that is very close to the critical value between recollapse and eternal expansion.

Multiverse hypotheses:
Main articles:  See also: Eternal inflation

Some speculative theories have proposed that our universe is but one of a set of disconnected universes, collectively denoted as the multiverse, challenging or enhancing more limited definitions of the universe.

Scientific multiverse models are distinct from concepts such as alternate planes of consciousness and simulated reality.

Max Tegmark developed a four-part classification scheme for the different types of multiverses that scientists have suggested in response to various problems in physics. An example of such multiverses is the one resulting from the chaotic inflation model of the early universe. 

Another is the multiverse resulting from the many-worlds interpretation of quantum mechanics. In this interpretation, parallel worlds are generated in a manner similar to quantum superposition and decoherence, with all states of the wave functions being realized in separate worlds. Effectively, in the many-worlds interpretation the multiverse evolves as a universal wavefunction.

If the Big Bang that created our multiverse created an ensemble of multiverses, the wave function of the ensemble would be entangled in this sense. Whether scientifically meaningful probabilities can be extracted from this picture has been and continues to be a topic of much debate, and multiple versions of the many-worlds interpretation exist.

(The subject of the interpretation of quantum mechanics is in general marked by disagreement.

The least controversial, but still highly disputed, category of multiverse in Tegmark's scheme is Level I. The multiverses of this level are composed by distant spacetime events "in our own universe".

Tegmark and others have argued that, if space is infinite, or sufficiently large and uniform, identical instances of the history of Earth's entire Hubble volume occur every so often, simply by chance. Tegmark calculated that our nearest so-called doppelgänger, is 1010115 metres away from us (a double exponential function larger than a googolplex).

However, the arguments used are of speculative nature. Additionally, it would be impossible to scientifically verify the existence of an identical Hubble volume.

It is possible to conceive of disconnected spacetimes, each existing but unable to interact with one another. An easily visualized metaphor of this concept is a group of separate soap bubbles, in which observers living on one soap bubble cannot interact with those on other soap bubbles, even in principle. 

According to one common terminology, each "soap bubble" of spacetime is denoted as a universe, whereas humans' particular spacetime is denoted as the universe, just as humans call Earth's moon the Moon. The entire collection of these separate spacetimes is denoted as the multiverse. With this terminology, different universes are not causally connected to each other. 
Others consider each of several bubbles created as part of chaotic inflation to be separate universes, though in this model these universes all share a causal origin.

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​Our Milky Way Galaxy
Pictured below: Milky Way and Our Location
The Milky Way is the galaxy that contains our Solar System.

Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye.

From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610.

Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies—now estimated to number as many as 200 billion galaxies in the observable universe.

The Milky Way is a barred spiral galaxy that has a diameter usually considered to be about 100,000–120,000 light-years but may be 150,000–180,000 light-years. The Milky Way is estimated to contain 100–400 billion stars. There are likely at least 100 billion planets in the Milky Way.

The Solar System is located within the disk, about 27,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm.

The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.

Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. The constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much of the mass of the Milky Way does not emit or absorb electromagnetic radiation. This mass has been termed "dark matter".

The rotational period is about 240 million years at the position of the Sun. The Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference.

The oldest stars in the Milky Way are nearly as old as the Universe itself and thus likely formed shortly after the Dark Ages of the Big Bang.

The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.

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​
Our Solar SystemPictured below: Image showing positions and names of the major planets in the Solar System.​
Our Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly.

Of those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.

The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with most of the remaining mass contained in Jupiter.

The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal.

The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called ices, such as water, ammonia and methane. All planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.

The Solar System also contains smaller objects. The asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids.

Within these populations are several dozen to possibly tens of thousands of objects large enough that they have been rounded by their own gravity. Such objects are categorized as dwarf planets. Identified dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. 

​In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust, freely travel between regions. Six of the planets, at least four of the dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after Earth's Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.

The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of interstellar wind; it extends out to the edge of the scattered disc.

The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way.

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​
​All About AstronomyPictured below: How amateur images are helping professional astronomers
These computer-generated images from the Copernicus Complexio cosmological simulation show stellar halos of Milky Way-like galaxies. The visible streams result from tidally disrupted satellite galaxies.
A.P. Cooper (National Tsing Hua University, Taiwan)/W. Hellwing and the Virgo Consortium
 (continues below)
​How amateur images are helping professional astronomers
Advances in our understanding of galaxy formation aren’t just coming from large, professional telescopes.
By David Martínez-delgado | Published: January 13, 2022

​Article continues below:

From the time Galileo first peered into his telescope until the middle of the 19th century, professional telescopes required the observer to look through an eyepiece. As a result, astronomers manually logged mountains of information and telescopic drawings in journals.

Then came photography. Almost from its inception, photography offered the tantalizing prospect of serving as a tool to discover and document new, hitherto-unseen phenomena. In fact, by the beginning of the 20th century, advancements in photography enabled career astronomers to lay down their pencils and trade their telescope eyepieces for glass plates coated with photographic emulsions.

In addition to appealing to professional astronomers, this potential captured the imagination of resourceful amateur astronomers equipped with modest instruments as well. One such amateur was sanitary engineer Andrew Common. In 1883, he took the first photograph of faint structures in the Orion Nebula (M42) that were not visible through an eyepiece. Others, photographing a plethora of objects, quickly followed.

Paving the way:

As the 21st century dawned, the digital imaging technology that had already replaced chemical photography at professional observatories began to trickle down into consumer products. This enabled amateur astronomers to purchase, at a reasonable cost, computer-controlled charge-coupled device (CCD) cameras expressly designed for use with small telescopes.

At the same time, motorized mounts driven by electronic maps of the sky enabled amateurs to place any celestial object at the center of an electronic imaging chip and track it with high precision.

As a result, modest equipment became a tool for obtaining ultra-deep images that could capture the outskirts of nearby massive galaxies and survey vast areas of the sky with unprecedented depth. This enabled a new type of collaboration between world-class amateur astroimagers and international teams of professional astronomers exploring one of the fundamental questions in modern astrophysics: How did massive galaxies like our Milky Way come to be?

The standard model of the universe’s formation predicts that the elegant galactic spirals we see today, including our own Milky Way, arose hierarchically. They did this by capturing much smaller galaxies, some only composed of dark matter. State-of-the-art computer models indicate the Local Group and its neighbors should still contain evidence of this ancient galactic cannibalism.

During the last decade, amateur telescopes have revealed, in many cases for the first time, an assortment of large-scale tidal structures around nearby massive galaxies. They also have imaged formerly unknown nearby low-surface-brightness star systems.

And amateurs using telephoto lenses have traced interactions between the Magellanic Clouds and other Milky Way satellite galaxies. All of these amazing images have provided evidence to support our understanding of galactic evolution as predicted by current simulations.

Amateurs at work:

Ultra-deep observations of nearby spiral galaxies and regions around them have been obtained by world-class American, European, and Chilean amateur astro-imagers. They operate privately owned observatories that use high-quality apochromatic and Ritchey-Chrétien telescopes with apertures between 4 and 32 inches (0.1 and 0.8 meter).

Each observing location features spectacularly dark, clear skies with typical seeing less than 1.5″.

These modest telescopes — and, in some cases, telephoto lenses — are coupled with off-the-shelf CCD cameras equipped with the latest generation of imaging chips. They can probe vast sky areas with unprecedented depth — approximately three magnitudes fainter than either classic photographic plate surveys like the Palomar Observatory Sky Survey or more recent digital surveys like the Sloan Digital Sky Survey (SDSS).

Camera sensitivity, fast operation, and lack of the competition for observing time typical of professional observatories places these low-cost robotic amateur facilities at the front line of ultra-deep imaging. They allow high-impact research of structures in nearby low-surface-brightness galaxies. Doing so requires multiple seven- and eight-hour exposures of each galactic target using high-throughput luminance (clear) filters for visible-light imaging. To capture fuzzy emission line structures in galactic halos, imagers use narrowband Hydrogen-alpha filters.

These observations demonstrate in several ways the feasibility of smaller telescopes to detect very faint diffuse structures in large fields around nearby galaxies.

First, small short-focal-length telescopes combined with single-chip cameras cover a larger field of view.

Second, the use of single-chip detectors also makes it easier to flatten the external regions around galaxies in comparison to standard multi-chip detector arrays used with professional telescopes.

Finally, observations with large telescopes are sometimes subject to glare from nearby bright stars and significant sky background variations from different sources. These artifacts complicate or mask the detection of faint structures, and their correction adds significant observing time overhead to the data-gathering process.

Searching for stellar streams:
​
Computer simulations predict that the stellar halos of massive galaxies contain an assortment of tidal debris streams that long exposures should reveal. The most spectacular examples are those that wrap around the host galaxy and roughly trace the orbit of the progenitor satellite galaxy that created them.

​One important highlight of this survey was the discovery of a stellar stream around NGC 4449, an isolated irregular galaxy similar to the Large Magellanic Cloud. This is the lowest-mass galaxy with a verified stellar stream. Such a discovery suggests satellite accretion also can play a significant role in building up stellar halos around low-mass galaxies as well as possibly triggering starbursts.

​Discovering satellite galaxies:

Searching for stellar streams with deep amateur images has also led to the discovery of numerous faint dwarf satellite galaxies around a handful of nearby spirals. This is intriguing because sophisticated computer simulations predict a large number of small dark matter halos in the local universe.

But our theory of galaxy formation is still unclear as to how many of these are in the form of luminous star systems. Therefore, astronomers want to conduct a full inventory of dwarf galaxies, both those orbiting as satellites and isolated dwarfs that are in the vicinity of nearby massive galaxies. The only way to detect them is by surveying vast regions with deep images.

Only a few organized astroimaging groups are searching for low-surface-brightness satellite galaxies. Some members of the Stellar Tidal Stream Survey are also involved in the Dwarf Galaxy Survey with Amateur Telescopes.

Additionally, the Tief Belichtete (Very Long Exposed) Galaxies project is run by German and Austrian imagers. These groups look for dwarf galaxies in long-exposure images using software that searches for likely candidates and then extracts their photometric and structural characteristics.

Isolated dwarf spheroidal galaxies are made exclusively of old stars with little gas to fuel star formation. These distant star systems are of huge interest because they act as laboratories where astronomers can study why they stopped forming stars about 10 billion years ago.

For example, Donatiello I is a dwarf spheroidal galaxy discovered by Italian astroimager Giuseppe Donatiello during a visual inspection of a deep image produced with a 5-inch refractor. The discovery was subsequently confirmed with SDSS images and follow-up observations by the 3.6-meter Galileo and the 10.4-meter Gran TeCan telescopes, both located in the Canary Islands.

​This low-surface-brightness stellar system, located about 1° from Mirach (Beta [β] Andromedae), is suspected to be the most isolated dwarf galaxy in the Local Group.
Picture Above:  Located in the constellation Leo, extensive debris shells from the accretion of one or more long-gone satellite galaxies encompass spiral galaxy NGC 3521 like a bubble. Data for this image were collected through a 20-inch amateur telescope.
R. Jay GaBanyic

Magellanic Cloud interactions:

Another important approach to understanding the formation and evolution of dwarf galaxies is studying the Milky Way’s two largest galactic satellites, the Magellanic Clouds, through mapping their outskirts. These regions should still contain clues about past interactions between the Clouds that left visible imprints such as distortions, clumps, arcs, and dense stellar areas.

With that purpose in mind, we performed a deep, wide-field imaging survey of the periphery of the Magellanic Clouds. Inspired by the photographic plate work of French astronomer Gérard de Vaucouleurs in the ’50s, this modern project used low-cost telephoto lenses to obtain deep images of the Clouds. One panoramic view revealed a never-before-seen, dense, shell-like area of stars in the outskirts of the Small Magellanic Cloud.

Research using photometric observations from the Survey of the Magellanic Stellar History revealed the shell is mainly composed of young stars. It suggests the structure resulted from a star-formation event, likely triggered by gravitational interaction with the Large Magellanic Cloud and/or the Milky Way about 150 million years ago. Recent studies with the Hubble Space Telescope found the two Magellanic Clouds had a head-on collision about the same time.

Can amateurs contribute?

Based on these results, it’s clear that advances in our understanding of galaxy formation needn’t be obtained only by large, professional instruments. Important scientific results that further our understanding of how the universe formed can be obtained when amateurs with modest telescopes collaborate with professionals with big objectives.

[End of Article]

To locate amateur astronomy retailers near you, Google "Amateeur Astronomy Retailers"
___________________________________________________________________________

Outline of Astronomy (Wikipedia)

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Space Telescopes, featuring: The James Webb Space Telescope ​and Hubble Space Telescope
Pictured: comparison of resolution gain for the James Webb Space Telescope over the (earlier) Hubble Space Telescope.
A space telescope or space observatory is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971.

Space telescopes avoid the filtering and distortion (scintillation) of electromagnetic radiation which they observe, and avoid light pollution which ground-based observatories encounter.

They are divided into two types: Satellites which map the entire sky (astronomical survey), and satellites which focus on selected astronomical objects or parts of the sky and beyond.

Space telescopes are distinct from Earth imaging satellites, which point toward Earth for satellite imaging, applied for weather analysis, espionage, and other types of information gathering.

History:

Wilhelm Beer and Johann Heinrich Mädler in 1837 discussed the advantages of an observatory on the Moon. 

In 1946, American theoretical astrophysicist Lyman Spitzer proposed a telescope in space. Spitzer's proposal called for a large telescope that would not be hindered by Earth's atmosphere. After lobbying in the 1960s and 70s for such a system to be built, Spitzer's vision ultimately materialized into the Hubble Space Telescope, which was launched on April 24, 1990 by the Space Shuttle Discovery (STS-31).

The first operational space telescopes were the American Orbiting Astronomical Observatory, OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971.

Advantages:

Performing astronomy from ground-based observatories on Earth is limited by the filtering and distortion of electromagnetic radiation (scintillation or twinkling) due to the atmosphere.

A telescope orbiting Earth outside the atmosphere is subject neither to twinkling nor to light pollution from artificial light sources on Earth. As a result, the angular resolution of space telescopes is often much higher than a ground-based telescope with a similar aperture. Many larger terrestrial telescopes, however, reduce atmospheric effects with adaptive optics.

​Space-based astronomy is more important for frequency ranges that are outside the optical window and the radio window, the only two wavelength ranges of the electromagnetic spectrum that are not severely attenuated by the atmosphere.

For example, X-ray astronomy is nearly impossible when done from Earth, and has reached its current importance in astronomy only due to orbiting X-ray telescopes such as the Chandra X-ray Observatory and the XMM-Newton observatory. Infrared and ultraviolet are also largely blocked.

Disadvantages:

Space telescopes are much more expensive to build than ground-based telescopes. Due to their location, space telescopes are also extremely difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle, but most space telescopes cannot be serviced at all.

Future of space observatories:

Satellites have been launched and operated by NASA, ISRO, ESA, CNSA, JAXA and the Soviet space program (later succeeded by Roscosmos of Russia). As of 2022, many space observatories have already completed their missions, while others continue operating on extended time.

However, the future availability of space telescopes and observatories depends on timely and sufficient funding. While future space observatories are planned by NASA, JAXA and the CNSA, scientists fear that there would be gaps in coverage that would not be covered immediately by future projects and this would affect research in fundamental science. 

For example, there was a fear that there would be a gap in coverage between the Hubble Space Telescope and the James Webb Space Telescope (JWST).

On 16 January 2023, NASA announced preliminary considerations of several future space telescope programs, including the following:
List of space telescopes:

​For a more comprehensive list, see List of space telescopes.

See also:___________________________________________________________________________

James Webb Space Telescope

The James Webb Space Telescope (JWST) is a space telescope currently conducting infrared astronomy.

As the largest optical telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, distant, or faint for the Hubble Space Telescope. 

This enables investigations across many fields of astronomy and cosmology, such as observation of the first stars, the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.

The U.S. National Aeronautics and Space Administration (NASA) led Webb's design and development and partnered with two main agencies: the European Space Agency (ESA) and the Canadian Space Agency (CSA).

The NASA Goddard Space Flight Center (GSFC) in Maryland managed telescope development, while the Space Telescope Science Institute in Baltimore on the Homewood Campus of Johns Hopkins University currently operates Webb.

The primary contractor for the project was Northrop Grumman. The telescope is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.

The James Webb Space Telescope was launched on 25 December 2021 on an Ariane 5 rocket from Kourou, French Guiana, and arrived at the Sun–Earth L2 Lagrange point in January 2022. The first Webb image was released to the public via a press conference on 11 July 2022.

Webb's primary mirror consists of 18 hexagonal mirror segments made of gold-plated beryllium, which combined create a 6.5-meter-diameter (21 ft) mirror, compared with Hubble's 2.4 m (7 ft 10 in). This gives Webb a light-collecting area of about 25 square meters, about six times that of Hubble.

Unlike Hubble, which observes in the near ultraviolet and visible (0.1 to 0.8 μm), and near infrared (0.8–2.5 μm) spectra, Webb observes a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm).

The telescope must be kept extremely cold, below 50 K (−223 °C; −370 °F), such that the infrared light emitted by the telescope itself does not interfere with the collected light. It is deployed in a solar orbit near the Sun–Earth L2 Lagrange point, about 1.5 million kilometers (930,000 mi) from Earth, where its five-layer sunshield protects it from warming by the Sun, Earth, and Moon.

Initial designs for the telescope, then named the Next Generation Space Telescope, began in 1996. Two concept studies were commissioned in 1999, for a potential launch in 2007 and a US$1 billion budget. The program was plagued with enormous cost overruns and delays; a major redesign in 2005 led to the current approach, with construction completed in 2016 at a total cost of US$10 billion. The high-stakes nature of the launch and the telescope's complexity were remarked upon by the media, scientists, and engineers.

Features:

The mass of the James Webb Space Telescope is about half that of the Hubble Space Telescope. Webb has a 6.5 m (21 ft)-diameter gold-coated beryllium primary mirror made up of 18 separate hexagonal mirrors. The mirror has a polished area of 26.3 m2 (283 sq ft), of which 0.9 m2 (9.7 sq ft) is obscured by the secondary support struts, giving a total collecting area of 25.4 m2 (273 sq ft).

This is over six times larger than the collecting area of Hubble's 2.4 m (7.9 ft) diameter mirror, which has a collecting area of 4.0 m2 (43 sq ft). The mirror has a gold coating to provide infrared reflectivity and this is covered by a thin layer of glass for durability.
Webb is designed primarily for near-infrared astronomy, but can also see orange and red visible light, as well as the mid-infrared region, depending on the instrument being used.

It can detect objects up to 100 times fainter than Hubble can, and objects much earlier in the history of the universe, back to redshift z≈20 (about 180 million years cosmic time after the Big Bang). 

For comparison, the earliest stars are thought to have formed between z≈30 and z≈20 (100–180 million years cosmic time), and the first galaxies may have formed around redshift z≈15 (about 270 million years cosmic time). Hubble is unable to see further back than very early reionization at about z≈11.1 (galaxy GN-z11, 400 million years cosmic time).

The design emphasizes the near to mid-infrared for several reasons:
  • high-redshift (very early and distant) objects have their visible emissions shifted into the infrared, and therefore their light can be observed today only via infrared astronomy;
  • infrared light passes more easily through dust clouds than visible light;
  • colder objects such as debris disks and planets emit most strongly in the infrared;
  • these infrared bands are difficult to study from the ground or by existing space telescopes such as Hubble.

Ground-based telescopes must look through Earth's atmosphere, which is opaque in many infrared bands. Even where the atmosphere is transparent, many of the target chemical compounds, such as water, carbon dioxide, and methane, also exist in the Earth's atmosphere, vastly complicating analysis.

Existing space telescopes such as Hubble cannot study these bands since their mirrors are insufficiently cool (the Hubble mirror is maintained at about 15 °C [288 K; 59 °F]) which means that the telescope itself radiates strongly in the relevant infrared bands.

Webb can also observe objects in the Solar System at an angle of more than 85° from the Sun and having an apparent angular rate of motion less than 0.03 arc seconds per second. This includes Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, their satellites, and comets, asteroids and minor planets at or beyond the orbit of Mars. Webb has the near-IR and mid-IR sensitivity to be able to observe virtually all known Kuiper Belt Objects. 

In addition, it can observe opportunistic and unplanned targets within 48 hours of a decision to do so, such as supernovae and gamma ray bursts.

Location and orbit:

Webb operates in a halo orbit, circling around a point in space known as the Sun–Earth L2 Lagrange point, approximately 1,500,000 km (930,000 mi) beyond Earth's orbit around the Sun. Its actual position varies between about 250,000 and 832,000 km (155,000–517,000 mi) from L2 as it orbits, keeping it out of both Earth and Moon's shadow.

By way of comparison, Hubble orbits 550 km (340 mi) above Earth's surface, and the Moon is roughly 400,000 km (250,000 mi) from Earth. Objects near this Sun–Earth L2 point can orbit the Sun in synchrony with the Earth, allowing the telescope to remain at a roughly constant distance with continuous orientation of its sunshield and equipment bus toward the Sun, Earth and Moon.

Combined with its wide shadow-avoiding orbit, the telescope can simultaneously block incoming heat and light from all three of these bodies and avoid even the smallest changes of temperature from Earth and Moon shadows that would affect the structure, yet still maintain uninterrupted solar power and Earth communications on its sun-facing side.

This arrangement keeps the temperature of the spacecraft constant and below the 50 K (−223 °C; −370 °F) necessary for faint infrared observations.
​
Sunshield protection:
Main article: James Webb Space Telescope sunshield

To make observations in the infrared spectrum, Webb must be kept under 50 K (−223.2 °C; −369.7 °F); otherwise, infrared radiation from the telescope itself would overwhelm its instruments. Its large sunshield blocks light and heat from the Sun, Earth, and Moon, and its position near the Sun–Earth L2 keeps all three bodies on the same side of the spacecraft at all times. 

Its halo orbit around the L2 point avoids the shadow of the Earth and Moon, maintaining a constant environment for the sunshield and solar arrays. The resulting stable temperature for the structures on the dark side is critical to maintaining precise alignment of the primary mirror segments.

The five-layer sunshield, each layer as thin as a human hair, is made of Kapton E film, coated with aluminum on both sides and a layer of doped silicon on the Sun-facing side of the two hottest layers to reflect the Sun's heat back into space. Accidental tears of the delicate film structure during deployment testing in 2018 led to further delays to the telescope.

The sunshield was designed to be folded twelve times (concertina style) so that it would fit within the Ariane 5 rocket's payload fairing, which is 4.57 m (15.0 ft) in diameter, and 16.19 m (53.1 ft) long. The shield's fully deployed dimensions were planned as 14.162 m × 21.197 m (46.46 ft × 69.54 ft).

Keeping within the shadow of the sunshield limits the field of regard of Webb at any given time. The telescope can see 40 percent of the sky from any one position, but can see all of the sky over a period of six months.

Optics:
Main article: Optical Telescope Element

Webb's primary mirror is a 6.5 m (21 ft)-diameter gold-coated beryllium reflector with a collecting area of 25.4 m2 (273 sq ft). If it had been designed as a single, large mirror, it would have been too large for existing launch vehicles.

The mirror is therefore composed of 18 hexagonal segments (a technique pioneered by Guido Horn d'Arturo), which unfolded after the telescope was launched. Image plane wavefront sensing through phase retrieval is used to position the mirror segments in the correct location using precise actuators.

Subsequent to this initial configuration, they only need occasional updates every few days to retain optimal focus. This is unlike terrestrial telescopes, for example the Keck telescopes, which continually adjust their mirror segments using active optics to overcome the effects of gravitational and wind loading. 

The Webb telescope uses 132 small actuation motors to position and adjust the optics The actuators can position the mirror with 10 nanometer accuracy.

Webb's optical design is a three-mirror anastigmat, which makes use of curved secondary and tertiary mirrors to deliver images that are free from optical aberrations over a wide field.

The secondary mirror is 0.74 m (2.4 ft) in diameter. In addition, there is a fine steering mirror which can adjust its position many times per second to provide image stabilization.

Photographs taken by Webb have six spikes plus two fainter ones due to the spider supporting the secondary mirror.

Scientific instruments:

​The Integrated Science Instrument Module (ISIM) is a framework that provides electrical power, computing resources, cooling capability as well as structural stability to the Webb telescope. It is made with bonded graphite-epoxy composite attached to the underside of Webb's telescope structure. The ISIM holds the four science instruments and a guide camera.
  • NIRCam (Near Infrared Camera) is an infrared imager which has spectral coverage ranging from the edge of the visible (0.6 μm) through to the near infrared (5 μm). There are 10 sensors each of 4 megapixels. NIRCam serves as the observatory's wavefront sensor, which is required for wavefront sensing and control activities, used to align and focus the main mirror segments. NIRCam was built by a team led by the University of Arizona, with principal investigator Marcia J. Rieke.
  • NIRSpec (Near Infrared Spectrograph) performs spectroscopy over the same wavelength range. It was built by the European Space Agency at ESTEC in Noordwijk, Netherlands. The leading development team includes members from Airbus Defence and Space, Ottobrunn and Friedrichshafen, Germany, and the Goddard Space Flight Center; with Pierre Ferruit (École normale supérieure de Lyon) as NIRSpec project scientist. The NIRSpec design provides three observing modes: a low-resolution mode using a prism, an R~1000 multi-object mode, and an R~2700 integral field unit or long-slit spectroscopy mode. Switching of the modes is done by operating a wavelength preselection mechanism called the Filter Wheel Assembly, and selecting a corresponding dispersive element (prism or grating) using the Grating Wheel Assembly mechanism. Both mechanisms are based on the successful ISOPHOT wheel mechanisms of the Infrared Space Observatory. The multi-object mode relies on a complex micro-shutter mechanism to allow for simultaneous observations of hundreds of individual objects anywhere in NIRSpec's field of view. There are two sensors, each of 4 megapixels.
  • MIRI (Mid-Infrared Instrument) measures the mid-to-long-infrared wavelength range from 5 to 27 μm. It contains both a mid-infrared camera and an imaging spectrometer. MIRI was developed as a collaboration between NASA and a consortium of European countries, and is led by George Rieke (University of Arizona) and Gillian Wright (UK Astronomy Technology Centre, Edinburgh, Scotland). The temperature of the MIRI must not exceed 6 K (−267 °C; −449 °F): a helium gas mechanical cooler sited on the warm side of the environmental shield provides this cooling.
  • FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), led by the Canadian Space Agency under project scientist John Hutchings (Herzberg Astronomy and Astrophysics Research Centre), is used to stabilize the line-of-sight of the observatory during science observations. Measurements by the FGS are used both to control the overall orientation of the spacecraft and to drive the fine steering mirror for image stabilization. The Canadian Space Agency also provided a Near Infrared Imager and Slitless Spectrograph (NIRISS) module for astronomical imaging and spectroscopy in the 0.8 to 5 μm wavelength range, led by principal investigator René Doyon at the Université de Montréal. Although they are often referred together as a unit, the NIRISS and FGS serve entirely different purposes, with one being a scientific instrument and the other being a part of the observatory's support infrastructure.

NIRCam and MIRI feature starlight-blocking coronagraphs for observation of faint targets such as extrasolar planets and circumstellar disks very close to bright stars.

Spacecraft bus:
Main article: Spacecraft bus (James Webb Space Telescope)

​The spacecraft bus is the primary support component of the James Webb Space Telescope, hosting a multitude of computing, communication, electric power, propulsion, and structural parts. Along with the sunshield, it forms the spacecraft element of the space telescope. The spacecraft bus is on the Sun-facing "warm" side of the sunshield and operates at a temperature of about 300 K (27 °C; 80 °F).

The structure of the spacecraft bus has a mass of 350 kg (770 lb), and must support the 6,200 kg (13,700 lb) space telescope. It is made primarily of graphite composite material. It was assembled in California, assembly was completed in 2015, and then it had to be integrated with the rest of the space telescope leading up to its 2021 launch.

The spacecraft bus can rotate the telescope with a pointing precision of one arcsecond, and isolates vibration down to two milliarcseconds.

Webb has two pairs of rocket engines (one pair for redundancy) to make course corrections on the way to L2 and for station keeping – maintaining the correct position in the halo orbit.

Eight smaller thrusters are used for attitude control – the correct pointing of the spacecraft. The engines use hydrazine fuel (159 liters or 42 U.S. gallons at launch) and dinitrogen tetroxide as oxidizer (79.5 liters or 21.0 U.S. gallons at launch).

Servicing:

Webb is not intended to be serviced in space. A crewed mission to repair or upgrade the observatory, as was done for Hubble, would not currently be possible, and according to NASA Associate Administrator Thomas Zurbuchen, despite best efforts, an uncrewed remote mission was found to be beyond current technology at the time Webb was designed.

During the long Webb testing period, NASA officials referred to the idea of a servicing mission, but no plans were announced. Since the successful launch, NASA has stated that nevertheless limited accommodation was made to facilitate future servicing missions.

These accommodations included precise guidance markers in the form of crosses on the surface of Webb, for use by remote servicing missions, as well as refillable fuel tanks, removable heat protectors, and accessible attachment points.

Software:

Ilana Dashevsky and Vicki Balzano write that Webb uses a modified version of JavaScript, called Nombas ScriptEase 5.00e, for its operations; it follows the ECMAScript standard and "allows for a modular design flow, where on-board scripts call lower-level scripts that are defined as functions".

"The JWST science operations will be driven by ASCII (instead of binary command blocks) on-board scripts, written in a customized version of JavaScript. The script interpreter is run by the flight software, which is written in C++. The flight software operates the spacecraft and the science instruments."

Click on any blue hyperlink below for more about the James Webb Space Telescope:___________________________________________________________________________​

Hubble Space Telescope:

​The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy.

The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft.

Hubble features a 2.4 m (7 ft 10 in) mirror, and its five main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space.

Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.

Space telescopes were proposed as early as 1923, and the Hubble telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency. Its intended launch was in 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster.

Hubble was finally launched in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.

Hubble is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003), but after NASA administrator Michael D. Griffin approved it, the servicing mission was completed in 2009.

Hubble completed 30 years of operation in April 2020 and is predicted to last until 2030–2040.

Hubble forms the visible light component of NASA's Great Observatories program, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope (which covers the infrared bands). The mid-IR-to-visible band successor to the Hubble telescope is the James Webb Space Telescope (JWST), which was launched on December 25, 2021, with the Nancy Grace Roman Space Telescope due to follow in 2027.

Click on any of the following blue hyperlinks for more about the Hubble Space Telescope:






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United States Space Force (Military Branch) Pictured below: Organization of the United States Space Force within the Department of Defense
​The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces and the world's only dedicated independent space force. Along with the U.S. Air Force, the Space Force is part of the Department of the Air Force, led by the secretary of the Air Force.

The military heads of the Space Force are the chief of space operations, who is one of the Joint Chiefs of Staff, and vice chief of space operations.

The Space Force is the smallest U.S. armed service, consisting of 8,600 military personnel. The Space Force operates 77 spacecraft in total across various programs such as: 
Under the Goldwater–Nichols Act, the Space Force is responsible for organizing, training, and equipping space forces, which are then presented to the unified combatant commands, predominantly to United States Space Command, for operational employment.

The U.S. Space Force traces its roots to the beginning of the Cold War, with the first military space programs starting in 1945.

In 1954, the Air Force established the Western Development Division, the world's first dedicated space organization, under General Bernard Schriever and unified its space forces under Air Force Space Command in 1982. U.S. space forces have participated in every U.S. conflict since the Vietnam War, most notably in the Persian Gulf War, often referred to as the first "space war."

The first discussion of a U.S. Space Force occurred under President Dwight Eisenhower's administration in 1958 and it was nearly established in 1982 by President Ronald Reagan as part of the Strategic Defense Initiative. The 2001 Space Commission argued for the creation of a Space Corps around 2007–2011, but due to the September 11 attacks and war on terror any plans were put on hold.

On 20 December 2019, the United States Space Force Act was signed into law establishing the U.S. Space Force as the first new independent military service since the Army Air Forces were reorganized as the U.S. Air Force in 1947.

Mission:

As outlined in 10 U.S.C. § 9081 and originally introduced in the United States Space Force Act, the Space Force is organized, trained, and equipped to:
  1. Provide freedom of operation for the United States in, from, and to space;
  2. Conduct space operations; and
  3. Protect the interests of the United States in space.

The Department of Defense further defines the specified functions of the Space Force to:
  1. Provide freedom of operation for the United States in, from, and to space.
  2. Provide prompt and sustained space operations.
  3. Protect the interests of the United States in space.
  4. Deter aggression in, from, and to space.
  5. Conduct space operations.

Cornerstone responsibilities and core competencies:

On 10 August 2020, the Space Force released its capstone doctrine, Spacepower: Doctrine for Space Forces, further expanding on its enumerated missions and duties.

In Spacepower, the Space Force defines its three cornerstone responsibilities of military space forces, which it articulates why spacepower is vital to U.S. prosperity and security.
  1. Preserve freedom of action: Unfettered access to and freedom to operate in space is a vital national interest; it is the ability to accomplish all four components of national power – diplomatic, information, military, and economic – of a nation’s implicit or explicit space strategy. Military space forces fundamentally exist to protect, defend, and preserve this freedom of action.
  2. Enable Joint Lethality and Effectiveness: Space capabilities strengthen operations in the other domains of warfare and reinforce every Joint function – the US does not project or employ power without space. At the same time, military space forces must rely on military operations in the other domains to protect and defend space freedom of action. Military space forces operate as part of the closely integrated Joint Force across the entire conflict continuum in support of the full range of military operations.
  3. Provide Independent Options: A central tenet of military spacepower is the ability to independently achieve strategic effects. In this capacity, military spacepower is more than an adjunct to landpower, seapower, airpower, and cyberpower. Across the conflict continuum, military spacepower provides national leadership with independent military options that advance the nation’s prosperity and security. Military space forces achieve national objectives by projecting power in, from, to space.

​The cornerstone responsibilities are executed through the five military spacepower core competencies:
  1. Space Security: establishes and promotes stable conditions for the safe and secure access to space activities for civil, commercial, intelligence community, and multinational partners.
  2. Combat Power Projection: integrates defensive and offensive operations to maintain a desired level of freedom of action relative to an adversary. Combat Power Projection in concert with other competencies enhances freedom of action by deterring aggression or compelling an adversary to change behavior.
  3. Space Mobility and Logistics (SML): enables movement and support of military equipment and personnel in the space domain, from the space domain back to Earth, and to the space domain.
  4. Information Mobility: provides timely, rapid and reliable collection and transportation of data across the range of military operations in support of tactical, operational, and strategic decision making.
  5. Space Domain Awareness (SDA) encompasses the effective identification, characterization and understanding of any factor associated with the space domain that could affect space operations and thereby impact the security, safety, economy, or environment of our Nation.

History:
Main article: History of the United States Space Force

Early military space development (1945–1961):

​Following the end of the World War II, each of the military services began to turn to space. General of the Army Henry H. Arnold, commander of the Army Air Forces identified spaceflight as a critical military capability, with each of the services developing parallel space and rocket programs.

In 1954 the Air Force created the first dedicated space organization in the entire world, creating the Western Development Division under General Bernard Schriever. The Army followed shortly after, establishing the Army Ballistic Missile Agency in 1955, led by General John Bruce Medaris and former German scientist Wernher von Braun. Both these organizations, along with the Naval Research Laboratory, were vital in developing the first American rockets and spacecraft.

The launch of Sputnik 1 and the initial failure of the Naval Research Laboratory's Project Vanguard reinvigorated the military space program, with the Army successfully launching America's first satellite, Explorer 1 on a Juno 1 rocket.

Sputnik also prompted a short-lived consolidation of military space under the Advanced Research Projects Agency. Despite concerns within the existing military services that the Advanced Research Project Agency would evolve into a U.S. Space Force, space authorities were returned to the Army, Navy, and Air Forces.

However, the newly established National Aeronautics and Space Administration absorbed the Army Ballistic Missile Agency and the Navy's Project Vanguard in 1959, leaving the Air Force mostly unscathed. In 1961, the Air Force was designated the military's executive agent for space, giving it leadership within the Department of Defense.

Space operations in the Cold War (1961–1982)

While the Air Force had overall leadership in space, the Army and Navy still had space missions, with the Army and Navy responsible for operating elements of satellite communications systems and the Navy leading the development and operation of satellite navigation systems.

Established in 1962 as the world's first military space operations command, the Navy Astronautics Group was created to operate the Navy's communication and navigation satellites. The first military employment of space forces occurred during the Vietnam War, with the Air Force using its weather and communications satellites to support ground and air operations in theater.

Early military spacraft included the Air Force's Defense Satellite Communications System, Vela nuclear dentation detection satellites, the Missile Defense Alarm System, and the Navy's Tranit and Timation navigation satellites. 

Each of the military services also provided significant support to NASA's civil space program, with the Army Ballistic Missile Agency's Project Adam forming the basis for NASA's Project Mercury. The Army and Air Force developed all of NASA's pre-Saturn V space launch vehicles, with the Army Ballistic Missile Agency designing the Redstone and Saturn I, while the Air Force repurposed the Atlas. 

The Air Force, Marine Corps, and Navy provided all of NASA's early astronauts and led astronaut rescue and recovery missions. The Air Force also provided range support for NASA launches from Cape Canaveral Air Force Station.

The X-20 Dyna Soar was intended to be the Air Force's first spaceplane. Concerned by Soviet orbital flights, the Air Force strongly pushed for a crewed military spaceflight program. General Curtis LeMay drew parallels between space operations in the 1960s and air operations in World War I, describing how airplanes quickly evolved from peaceful chivalric, unarmed reconnaissance flights to combat efforts designed to destroy enemy air superiority and that it would be naïve to believe that the same trends were not expected to be seen and prepared for in space.

Although the Air Force made significant progress towards the development of the Boeing X-20 Dyna-Soar spaceplane, Manned Orbiting Laboratory, and Blue Gemini, ultimately political opposition from the Department of Defense prevented them from being operationally fielded.

Although unsuccessful in fielding human military spacecraft, the Air Force and Army successfully led the development of anti-satellite weapons. The Air Force's Project SAINT was an early satellite inspector, which also had "satellite neutralization" capabilities, however it was canceled in 1962 by the Defense Department when details were leaked to The New York Times. 

As the lead service for missile defense, the Army also developed the Nike Zeus anti-ballistic missile to have satellite interception capability. On 23 May 1963, a Nike Zeus launched from Kwajalein Atoll successfully intercepted a Agena-D target vehicle and was put on ready alert until 1964. The Army's Nike Zeus ASAT was replaced by the Air Force's Program 437, which used nuclear-tipped Thor missile to intercept satellites, until the program was deactivated in 1975.

The Strategic Defense Initiative and Persian Gulf War (1982-2001):

Dissatisfied with the current status of military space operations within the Air Force, Representative Ken Kramer introduced a resolution to rename the U.S. Air Force to the U.S. Aerospace Force to force a new focus on space and rumors spread that President Ronald Reagan would announce the establishment of a U.S. Space Force.

These two developments spurred Air Force leadership into action, establishing Air Force Space Command in 1982 to consolidate its space forces under a single major command.

In 1985, President Regan created United States Space Command as a unified combatant command for space, with Air Force Space Command as its primary service provider. Naval Space Command was established 1985 and the Army Space Command was created in 1988 to serve as their service components to U.S. Space Command.

The establishment of U.S. Space Command, Air Force Space Command, and the Strategic Defense Initiative by President Regan led to a renaissance of military space operations. In September 1985, a U.S. Air Force F-15 conducted a test launch of the ASM-135 anti-satellite missile, destroying the Solwind satellite.

The Air Force and Navy proceeded to deploy modernized satellites, such as:
​The Persian Gulf War proved to be a decisive moment for military space operations, with space forces providing critical tactical support to coalition land, air, and naval forces. Over sixty satellites provided 90% of theater communications and command and control for an multinational army of 500,000 troops, weather support for mission planners, early warning of Iraqi Scud missile launches, and satellite navigation for air and land forces moving across a featureless desert. This critical degree of support led to the Persian Gulf War being coined "the first Space War."

Despite the decisive role played by space forces during the Persian Gulf War, there were a number of Air Force generals who sought to merge air and space into a seamless aerospace continuum, to the detriment of space.

This drew the ire of prominent congressmen, with Senator Bob Smith, in particular, proposing an independent space force. Congress established the establishing the commission to Assess United States National Security Space Management and Organization, better known as the Space Comission, to investigate the matter.

Chaired by Donald Rumsfeld, the Space Commission released its report in 2001. Key recommendations included no longer exclusively assigning pilots to be commander of U.S. Space Command. The commission noted that fewer than 20% of top space leaders had a space background, with the majority being drawn from the pilot, Army Air Defense Artillery, or nuclear and missile operations and that the average individual had only spent 2.5 years of their careers in space positions.

Ultimately, the Space Commission recommended the establishment of a separate Space Force as a military branch in the long term, with the establishment of a Space Corps, analogous to the Army Air Forces within the U.S. Air Force in the between 2007 and 2011.

Space Force independence (2001-2019)

Despite the recommendations of the Space Commission, the September 11 attacks and Global War on Terror prevented the continued evolution of military space forces.

To make way for the establishment of U.S. Northern Command, U.S. Space Command was shut down and its functions were merged into United States Strategic Command in 2002.

Naval Space Command was shut down shortly prior to U.S. Space Command, transferring the Naval Space Surveillance System to Air Force Space Command. 

Army Space Command was first subordinated to Army Strategic Defense Command in 1992, with Army Space Command still existing under the new Army Space and Strategic Defense Command, renamed Army Space and Missile Defense Command in 1997. 

Certain Space Commission recommendations were implemented, such as transferring the Space and Missile Systems Center from Air Force Materiel Command to Air Force Space Command.

Air Force Space Command provided direct support to Operation Enduring Freedom, enabling satellite communications, global positioning system enhancements, and deployed personnel to support counterterrorism operations.

​For Operation Iraqi Freedom, the Air Force Space Command deployed space operators to forward operating bases in the Middle East and the Defense Satellite Communications System provided 80% of bandwidth for allied forces in theater, while 85% of Milstar communications capacity was directed towards support of tactical forces.

​Following the inactivation of U.S. Space Command in 2002, Russia and China began developing sophisticated on-orbit capabilities and an array of counter-space weapons. In particular, China conducted the 2007 Chinese anti-satellite missile test, destroying its Fengyun spacecraft, which, according to NASA, created 2,841 high-velocity debris items, a larger amount of dangerous space junk than any other space event in history.

On 29 August 2019, United States Space Command was reestablished as a geographic combatant command. In 2008, U.S. Strategic Command conducted Operation Burnt Frost to destroy a non-functioning National Reconnaissance Office satellite, before its toxic hydrazine tank could reenter and cause potential harm to human safety, with a RIM-161 Standard Missile 3 launched from the USS Lake Erie.

Growing impatient with the Air Force, Representatives Jim Cooper (D-TN) and Mike Rogers (R-AL) unveiled a bipartisan proposal in the House of Representatives to establish the United States Space Corps as a separate military service within the Department of the Air Force to give space a greater cultural focus and help develop a leaner and faster space acquisitions system. 

The proposal passed in the House of Representatives, but was cut from the final bill in negotiations with the U.S. Senate.The Space Corps proposal was, in large part, spurred on by the development of the People's Liberation Army Strategic Support Force and the Russian Space Forces.

Legislative provisions for the Space Force were included in the 2020 National Defense Authorization Act, which was signed into law on 20 December 2019. The Space Force was established as the sixth armed service branch, with Air Force General John W. Raymond, the commander of Air Force Space Command and U.S. Space Command, becoming the first chief of space operations. On 14 January 2020, Raymond was officially sworn in as chief of space operations by Vice President Mike Pence.

The sixth service (2019-present)

Following independence, all of Air Force Space Command's 16,000 active duty and civilian airmen were transferred to the U.S. Space Force, including the: 
Wings and groups were replaced by deltas in 2020 and the Space Force's field commands were activated in 2020 and 2021. In 2020, the first Air Force space bases were renamed to Space Force bases. 

In September 2020, the Space Force and NASA signed a memorandum of understanding formally acknowledging the joint role of both agencies. This new memorandum replaced a similar document signed in 2006 between NASA and Air Force Space Command.

General Jay Raymond was followed into the service by on 3 April 2020 by Chief Master Sergeant Roger A. Towberman, who became the Space Force's first enlisted member and senior enlisted advisor of the Space Force, and 86 U.S. Air Force Academy cadets who became the first Space Force lieutenants on 18 April 2020. 

The Space Force also gained its first astronaut, with Colonel Michael S. Hopkins, the commander of SpaceX Crew-1, swearing into the Space Force from the International Space Station on 18 December 2020.

​The Space Force's first combat operations as a new service included providing early warning of Iranian Islamic Revolutionary Guard Corps Aerospace Force missile strikes against U.S. troops at Al Asad Airbase on 7 January 2020 through the 2nd Space Warning Squadron's Space Based Infrared System. 

The Space Force also monitored Russian Space Forces spacecraft which had been tailing U.S. government satellites.

One of the major reasons for creating the Space Force was consolidating military space activities across the Department of Defense. The Space Training and Readiness Delta (Provisional) was established in 2020 to bring over the remaining operational Air Force space activities spread across Air Education and Training Command and Air Combat Command, while Space Systems Command brought over the Air Force Life Cycle Management Center's Strategic Warning and Surveillance Systems Division in 2021. 

The Space Force accepted a record number of interservice transfers from the U.S. Army, U.S. Air Force, U.S. Navy, and U.S. Air Force. 

Additionally, in 2022 the Space Force accepted the transfer of the Naval Satellite Operations Center from the U.S. Navy and the Army's Satellite Operations Brigade, putting satellite communications under a single service for the first time. 

In 2023, the Space Force assumed responsibility for the Army's Joint Tactical Ground Station, putting all missile warning under the Space Force.

Organization:
Main articles:
The Space Force's field organizations consist of three different echelons of command:
  • Field commands (FLDCOM): Align with a specific mission focus and are typically led by a lieutenant general or major general, although smaller component field commands and Space Force elements may have officers ranging from lieutenant colonel to major general in command. Component field commands are the Space Force component to a unified combatant command.
  • Deltas are organized around a specific function, such as operations, training, or installation support and are typically led by a colonel. In rare cases, a delta may be commanded by a higher ranking officer, such as a major general in the case of Space Launch Delta 45. Deltas are equivalent to an Air Force wing or an Army brigade combat team.
  • Squadrons are focused on specific tactics and are led by a lieutenant colonel.

Each of the three major field commands has a distinctive color which is share by its subordinate units. Space Operations Command is platinum, Space Systems Command is gold, and Space Training and Readiness Command is Cannes Blue.

Headquarters Space Force

The U.S. Space Force is organized under the Department of the Air Force, alongside the U.S. Air Force. Civilian leadership is provided by the Secretary of the Air Force and under secretary of the Air Force. The most important assistant secretary of the Air Force for the Space Force is the Assistant Secretary of the Air Force for Space Acquisition and Integration, who is the only assistant secretary of the Air Force focused entirely on space and serves as the Space Force's service acquisition executive.

Military leadership is provided by the chief of space operations and vice chief of space operations, who are advised by the chief master sergeant of the Space Force. 

Headquarters Space Force, also known as the Office of the Chief of Space Operations or Space Staff, serves as the service's highest staff and headquarters element, is located at the Pentagon. It is led by the chief of space operations and the vice chief of space operations.

Click here for an image of the United States Space Command organization.

​Relationships with other space organizations:

Department of the Air Force and U.S. Air Force:
Main articles:  ​
The U.S. Space Force derives a significant degree of support from the Department of the Air Force and the U.S. Air Force. The Space Force only consist of operators and acquisitions, relying on the Air Force to provide airmen in support or other niche specialties. 

Air Force Materiel Command provides major command support to airmen assigned to the Space Force. The Space Force and Air Force continue to share a number of different organizations, such as the United States Air Force Academy and Air Force Research Laboratory.

Following the United States Space Force's establishment, calls have been made for the Department of the Air Force to rename itself the Department of the Air and Space Forces to acknowledge the Space Force, similar to calls made for the Department of the Navy to rename itself the Department of the Navy and Marine Corps. 

SpaceNews reported that a proposed name change was considered in 2018 and in 2019 the Air Force Association also called for renaming the department. In 2022, the Air Force Association renamed itself the Air & Space Forces Association, internally acting on its proposal to reflect the Space Force in the organization's name. 

In a 2021 article in the Space Force Journal, two Space Force officers also proposed a name change for the department.

National Aeronautics and Space Administration:
Main articles: 
The National Aeronautics and Space Administration (NASA) is an independent agency of the United States government responsible for civil spaceflight. NASA and the Space Force's predecessors in the Air Force have a long-standing cooperative relationship, with the Space Force supporting NASA launches out of Kennedy Space Center, to include range support. 

​NASA and the Space Force also partner on matters such as space domain awareness and planetary defense operations. Space Force members can be NASA astronauts, with Colonel Michael S. Hopkins, the commander of SpaceX Crew-1, commissioned into the Space Force from the International Space Station on 18 December 2020.

National Reconnaissance Office:
Main article: National Reconnaissance Office

​The National Reconnaissance Office (NRO) is a Department of Defense agency and a member of the United States Intelligence Community, responsible for designing, building, launching, and maintaining intelligence satellites. 

The Space Force executes National Reconnaissance Office space launches and consists of 40% of the agency's personnel. Proposals have been put forward, including by the Air Force Association and retired Air Force Lieutenant General David Deptula, to merge the NRO into the Space Force, transforming it into a Space Force Intelligence, Reconnaissance, and Surveillance Command and consolidating the entire national security space apparatus in the Space Force.

The USSF's Space Systems Command (SSC), in partnership with the National Reconnaissance Office, manages the National Security Space Launch (NSSL) program, which uses government and contract spacecraft to launch sensitive government payloads. 

NSSL supports both the USSF and NRO. NRO director Scolese has characterized his agency as critical to American space dominance and the Space Force, stating that NRO provides "unrivaled situational awareness and intelligence to the best imagery and signals data on the planet." Additionally, in August 2021, former NRO deputy director Lt. Gen. Michael Guetlein became commander of Space Systems Command.

Click on any of the following blue hyperlinks for more about the United States Space Force:







Neil deGrasse Tyson and Astrophysics Picture: Neil deGrasse Tyson appearing on the Late Show with Stephen Colbert -*
* -- This 1 Communication Trick Helps Neil deGrasse Tyson Explain Astrophysics to Anyone:

The astrophysicist Neil deGrasse Tyson (see below) has not one, but two books on the New York Times bestseller list. Most people don't rush to the bookstore to buy the newest book with the word "astrophysics" in the title, but they'll read Tyson's books. Then again, there aren't a lot of science books with the sentence, "Yes, Einstein was a badass."

Tyson connects with millions of people because he's an extraordinary communicator. But remarkably, one of the tools he's used to discuss today's most complex ideas is one of the world's most ancient writing instruments: quill and ink. 

You probably haven't used a feather quill dipped in ink, but Tyson has. He's a collector of writing instruments and can talk for an hour about his favorite quill pens or fountain pens, as does here. He's so passionate about the subject, he can even name the ink he used in a calligraphy pen more than thirty years ago to take lab notes. How do these pens make Tyson a better communicator? Listen carefully to what he told Wall Street Journal about his passion for ancient writing instruments:

​If you look at memorable speeches of the past, the rhythms happen to be in five-to-seven-word pulses. Then you learn that a single dip of a quill got you five or seven words. It may be that the rhythm was shaped by how much ink could sit in the shaft of a quill pen. As I write, I'm conscious of this. When you give a speech you don't want your sentences to be too long.
Short sentences are best for communication.Tyson's right.

Throughout history, great communicators understood the power of brevity. More than 2,000 years ago Aristotle, the father of persuasion, argued that sentences should be kept short so they are easy to read and easy to say out loud. 

Thomas Jefferson wrote the Declaration of Independence for the ear. He read his own sentences out loud to get a sense of rhythm. The first fountain pen wouldn't be introduced for another fifty years, so Jefferson was using quill and ink in his rented room in what is now known as the Declaration (Graff) House in Philadelphia. Visit the museum and you'll see a small vase holding feather quill pens.

Now listen for the "pulses" Tyson was talking about. You can almost see Jefferson re-dipping his pen.
  • We hold these truths to be self-evident [dip]
  • That all men are created equal [dip]
  • That they are endowed by their creator [dip]
  • With certain unalienable rights [dip]
  • That among these are [dip]
  • Life, liberty and the pursuit of happiness.

Abraham Lincoln used a dip pen to write the Gettysburg Address. At only 272 words, it was short on words but had a big impact. The most famous section was written and delivered in five to seven word "pulses." 
  • Fourscore and seven years ago (five)
  • Our fathers brought forth on this continent (seven)
  • A new nation (three)
  • Conceived in liberty (three)
  • And dedicated to the proposition (five)
  • That all men are created equal (six)

Tyson's observation is brilliant. It makes sense that great ideas were written and delivered in short bursts because the ink would run out! Regardless, it's the way we've become accustomed to listening to information.

If you want people to listen to your ideas, keep your words simple and sentences short. 
Tyson also learned to speak in short sentences very early in his career when he was the interim director of Hayden Planetarium in 1995. Scientists had discovered the first planet orbiting a star that was not the sun.

NBC News sent a reporter to interview Tyson. He gave a long, highly technical explanation. His comments didn't make the newscast. He realized that most people want shorter explanations--soundbites. For future interviews he rehearsed "three sentences abut a topic that are so tasty, you might want to tell someone else."

Give your listener tasty morsels about a topic--simple words and short sentences. If you do, your audience will be more likely to remember your ideas and to share them. 

[End of Article]
___________________________________________________________________________

Below, we start with a Wikipedia explanation of what Astrophysics is about, followed by the biography of Neil deGrass Tyson:

Astrophysics:

This article is about the use of physics to determine the nature of astronomical objects. For the use of physics to determine their positions and motions, see Celestial mechanics. For the physical study of the largest-scale structures of the universe, see Physical cosmology. For the journal, see Astrophysics (journal).

Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–what they are, rather than where they are." 

Among the subjects studied are:
Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include: 
Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including: 
In practice, modern astronomical research often involves a substantial amount of work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include their attempts to determine the properties of: 
Topics also studied by theoretical astrophysicists include: 

History:

Astronomy is an ancient science, long separated from the study of terrestrial physics. In the Aristotelian worldview, bodies in the sky appeared to be unchanging spheres whose only motion was uniform motion in a circle, while the earthly world was the realm which underwent growth and decay and in which natural motion was in a straight line and ended when the moving object reached its goal.

Consequently, it was held that the celestial region was made of a fundamentally different kind of matter from that found in the terrestrial sphere; either Fire as maintained by Plato, or Aether as maintained by Aristotle. 

During the 17th century, natural philosophers such as Galileo, Descartes, and Newton began to maintain that the celestial and terrestrial regions were made of similar kinds of material and were subject to the same natural laws. Their challenge was that the tools had not yet been invented with which to prove these assertions.

For much of the nineteenth century, astronomical research was focused on the routine work of measuring the positions and computing the motions of astronomical objects. A new astronomy, soon to be called astrophysics, began to emerge when William Hyde Wollaston and Joseph von Fraunhofer independently discovered that, when decomposing the light from the Sun, a multitude of dark lines (regions where there was less or no light) were observed in the spectrum. 

By 1860 the physicist, Gustav Kirchhoff, and the chemist, Robert Bunsen, had demonstrated that the dark lines in the solar spectrum corresponded to bright lines in the spectra of known gases, specific lines corresponding to unique chemical elements. Kirchhoff deduced that the dark lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere. 

In this way it was proved that the chemical elements found in the Sun and stars were also found on Earth.

Among those who extended the study of solar and stellar spectra was Norman Lockyer, who in 1868 detected radiant, as well as dark lines in solar spectra. Working with chemist Edward Frankland to investigate the spectra of elements at various temperatures and pressures, he could not associate a yellow line in the solar spectrum with any known elements. He thus claimed the line represented a new element, which was called helium, after the Greek Helios, the Sun personified.

In 1885, Edward C. Pickering undertook an ambitious program of stellar spectral classification at Harvard College Observatory, in which a team of woman computers, notably Williamina Fleming, Antonia Maury, and Annie Jump Cannon, classified the spectra recorded on photographic plates.

By 1890, a catalog of over 10,000 stars had been prepared that grouped them into thirteen spectral types. Following Pickering's vision, by 1924 Cannon expanded the catalog to nine volumes and over a quarter of a million stars, developing the Harvard Classification Scheme which was accepted for worldwide use in 1922.

In 1895, George Ellery Hale and James E. Keeler, along with a group of ten associate editors from Europe and the United States, established The Astrophysical Journal: An International Review of Spectroscopy and Astronomical Physics. 

It was intended that the journal would fill the gap between journals in astronomy and physics, providing: a venue for publication of articles on
  • astronomical applications of the spectroscope;
  • on laboratory research closely allied to astronomical physics, including wavelength determinations of metallic and gaseous spectra and experiments on radiation and absorption;
  • on theories of the Sun, Moon, planets, comets, meteors, and nebulae;
  • and on instrumentation for telescopes and laboratories.

Around 1920, following the discovery of the Hertzsprung–Russell diagram still used as the basis for classifying stars and their evolution, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars, in his paper The Internal Constitution of the Stars.

At that time, the source of stellar energy was a complete mystery; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einstein's equation E = mc2. This was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity), had not yet been discovered.

In 1925 Cecilia Helena Payne (later Cecilia Payne-Gaposchkin) wrote an influential doctoral dissertation at Radcliffe College, in which she applied Saha's ionization theory to stellar atmospheres to relate the spectral classes to the temperature of stars. Most significantly, she discovered that hydrogen and helium were the principal components of stars, not the composition of Earth.

Despite Eddington's suggestion, discovery was so unexpected that her dissertation readers (including Russell) convinced her to modify the conclusion before publication. However, later research confirmed her discovery.

By the end of the 20th century, studies of astronomical spectra had expanded to cover wavelengths extending from radio waves through optical, x-ray, and gamma wavelengths. In the 21st century, it further expanded to include observations based on gravitational waves.


​Observational astrophysics:

​​Observational astronomy is a division of the astronomical science that is concerned with recording and interpreting data, in contrast with theoretical astrophysics, which is mainly concerned with finding out the measurable implications of physical models.

It is the practice of observing celestial objects by using telescopes and other astronomical apparatus.

The majority of astrophysical observations are made using the electromagnetic spectrum:
Other than electromagnetic radiation, few things may be observed from the Earth that originate from great distances. A few gravitational wave observatories have been constructed, but gravitational waves are extremely difficult to detect. Neutrino observatories have also been built, primarily to study the Sun. Cosmic rays consisting of very high-energy particles can be observed hitting the Earth's atmosphere.

Observations can also vary in their time scale. Most optical observations take minutes to hours, so phenomena that change faster than this cannot readily be observed. However, historical data on some objects is available, spanning centuries or millennia.

On the other hand, radio observations may look at events on a millisecond timescale (millisecond pulsars) or combine years of data (pulsar deceleration studies). The information obtained from these different timescales is very different.

The study of the Sun has a special place in observational astrophysics. Due to the tremendous distance of all other stars, the Sun can be observed in a kind of detail unparalleled by any other star. Understanding the Sun serves as a guide to understanding of other stars.

The topic of how stars change, or stellar evolution, is often modeled by placing the varieties of star types in their respective positions on the Hertzsprung–Russell diagram, which can be viewed as representing the state of a stellar object, from birth to destruction.


Theoretical astrophysics:
See also: Theoretical astronomy

Theoretical astrophysicists use a wide variety of tools which include analytical models (for example, polytropes to approximate the behaviors of a star) and computational numerical simulations. Each has some advantages.

Analytical models of a process are generally better for giving insight into the heart of what is going on. Numerical models can reveal the existence of phenomena and effects that would otherwise not be seen.

Theorists in astrophysics endeavor to create theoretical models and figure out the observational consequences of those models. This helps allow observers to look for data that can refute a model or help in choosing between several alternate or conflicting models.

Theorists also try to generate or modify models to take into account new data. In the case of an inconsistency, the general tendency is to try to make minimal modifications to the model to fit the data. In some cases, a large amount of inconsistent data over time may lead to total abandonment of a model.

Topics studied by theoretical astrophysicists include stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in the universe; origin of cosmic rays; general relativity and physical cosmology, including string cosmology and astroparticle physics.

Relativistic astrophysics serves as a tool to gauge the properties of large-scale structures for which gravitation plays a significant role in physical phenomena investigated and as the basis for black hole (astro)physics and the study of gravitational waves.

Some widely accepted and studied theories and models in astrophysics, now included in the Lambda-CDM model, are:

Popularization:

The roots of astrophysics can be found in the seventeenth century emergence of a unified physics, in which the same laws applied to the celestial and terrestrial realms. There were scientists who were qualified in both physics and astronomy who laid the firm foundation for the current science of astrophysics.

In modern times, students continue to be drawn to astrophysics due to its popularization by the Royal Astronomical Society and notable educators such as prominent professors: 
The efforts of the early, late, and present scientists continue to attract young people to study the history and science of astrophysics. The television sitcom show The Big Bang Theory popularized the field of astrophysics with the general public, and featured some well known scientists like Stephen Hawking and Neil deGrasse Tyson (see next topic below).


See also: ___________________________________________________________________________

Neil deGrasse Tyson:

Neil deGrasse Tyson (born October 5, 1958) is an American astrophysicist, author, and science communicator.

Tyson studied at Harvard University, the University of Texas at Austin, and Columbia University. From 1991 to 1994, he was a postdoctoral research associate at Princeton University.

In 1994, he joined the Hayden Planetarium as a staff scientist and the Princeton faculty as a visiting research scientist and lecturer.

In 1996, he became director of the planetarium and oversaw its $210 million reconstruction project, which was completed in 2000.

Since 1996, he has been the director of the Hayden Planetarium at the Rose Center for Earth and Space in New York City. The center is part of the American Museum of Natural History, where Tyson founded the Department of Astrophysics in 1997 and has been a research associate in the department since 2003.

From 1995 to 2005, Tyson wrote monthly essays in the "Universe" column for Natural History magazine, some of which were later published in his books Death by Black Hole (2007) and Astrophysics for People in a Hurry (2017).

During the same period, he wrote a monthly column in StarDate magazine, answering questions about the universe under the pen name "Merlin". Material from the column appeared in his books Merlin's Tour of the Universe (1998) and Just Visiting This Planet (1998).

Tyson served on a 2001 government commission on the future of the U.S. aerospace industry and on the 2004 Moon, Mars and Beyond commission. He was awarded the NASA Distinguished Public Service Medal in the same year.

From 2006 to 2011, he hosted the television show NOVA ScienceNow on PBS. Since 2009, Tyson has hosted the weekly podcast StarTalk. A spin-off, also called StarTalk, began airing on National Geographic in 2015.

In 2014, he hosted the television series Cosmos: A Spacetime Odyssey, a successor to Carl Sagan's 1980 series Cosmos: A Personal Voyage. The U.S. National Academy of Sciences awarded Tyson the Public Welfare Medal in 2015 for his "extraordinary role in exciting the public about the wonders of science".


Early life and education:

Tyson was born in Manhattan as the second of three children, into a Catholic family living in the Bronx. 

His African-American father, Cyril deGrasse Tyson (1927–2016), was a sociologist, human resource commissioner for New York City mayor John Lindsay, and the first Director of Harlem Youth Opportunities Unlimited. 

His mother, Sunchita Maria Tyson (née Feliciano; born 1928), was a gerontologist for the U.S. Department of Health, Education and Welfare, and is of Puerto Rican descent.

Tyson has two siblings: Stephen Joseph Tyson and Lynn Antipas Tyson. Tyson's middle name, deGrasse, is from the maiden name of his paternal grandmother, who was born as Altima de Grasse in the British West Indies island of Nevis.

Tyson grew up in the Castle Hill neighborhood of the Bronx, and later in Riverdale. From kindergarten throughout high school, Tyson attended public schools in the Bronx: PS 36 Unionport, PS 81 Robert J. Christen, the Riverdale Kingsbridge Academy (MS 141), and graduated from The Bronx High School of Science in 1976 where he was captain of the wrestling team and editor-in-chief of the Physical Science Journal. 

His interest in astronomy began at the age of nine after visiting the sky theater of the Hayden Planetarium. He recalled that "so strong was that imprint [of the night sky] that I'm certain that I had no choice in the matter, that in fact, the universe called me." 

During high school, Tyson attended astronomy courses offered by the Hayden Planetarium, which he called "the most formative period" of his life. He credited Mark Chartrand III, director of the planetarium at the time, as his "first intellectual role model" and his enthusiastic teaching style mixed with humor inspired Tyson to communicate the universe to others the way he did.

When he was 14, he received a scholarship from the Explorers Club of New York to view the June 1973 total solar eclipse aboard the SS Canberra. The scientific cruise carried two thousand scientists, engineers, and enthusiasts, including Neil Armstrong, Scott Carpenter, and Isaac Asimov.

Tyson obsessively studied astronomy in his teen years, and eventually even gained some fame in the astronomy community by giving lectures on the subject at the age of fifteen. Astronomer Carl Sagan, who was a faculty member at Cornell University, tried to recruit Tyson to Cornell for undergraduate studies. 

In his book, The Sky Is Not the Limit, Tyson wrote: "My letter of application had been dripping with an interest in the universe. The admission office, unbeknownst to me, had forwarded my application to Carl Sagan's attention. Within weeks, I received a personal letter..."

Tyson revisited this moment on his first episode of Cosmos: A Spacetime Odyssey. Pulling out a 1975 calendar belonging to the famous astronomer, he found the day Sagan invited the 17-year-old to spend a day in Ithaca. Sagan had offered to put him up for the night if his bus back to the Bronx did not come.

Tyson said, "I already knew I wanted to become a scientist. But that afternoon, I learned from Carl the kind of person I wanted to become."

Tyson chose to attend Harvard where he majored in physics and lived in Currier House. He was a member of the crew team during his freshman year, but returned to wrestling, lettering in his senior year. He was also active in dance, in styles including jazz, ballet, Afro-Caribbean, and Latin Ballroom.

​Tyson earned a BA degree in physics at Harvard College in 1980 and then began his graduate work at the University of Texas at Austin, from which he received an MA degree in astronomy in 1983. By his own account, he did not spend as much time in the research lab as he should have. His professors encouraged him to consider alternative careers and the committee for his doctoral dissertation was dissolved, ending his pursuit of a doctorate from the University of Texas.

Tyson was a lecturer in astronomy at the University of Maryland from 1986 to 1987 and in 1988, he was accepted into the astronomy graduate program at Columbia University, where he earned an MPhil degree in astrophysics in 1989, and a PhD degree in astrophysics in 1991 under the supervision of Professor R. Michael Rich.

Rich obtained funding to support Tyson's doctoral research from NASA and the ARCS Foundation, enabling Tyson to attend international meetings in Italy, Switzerland, Chile, and South Africa and to hire students to help him with data reduction. 

​In the course of his thesis work, he observed using the 0.91 m telescope at the Cerro Tololo Inter-American Observatory in Chile, where he obtained images for the Calán/Tololo Supernova Survey helping to further their work in establishing Type Ia supernovae as standard candles.

During his thesis research at Columbia University, Tyson became acquainted with Professor David Spergel at Princeton University, who visited Columbia University in the course of collaborating with his thesis advisor on the Galactic bulge typically found in spiral galaxies.


Career

​Tyson's research has focused on observations in: 
He has held numerous positions at institutions including:
In 1994, Tyson joined the Hayden Planetarium as a staff scientist while he was a research affiliate in Princeton University. He became acting director of the planetarium in June 1995 and was appointed director in 1996. As director, he oversaw the planetarium's $210 million reconstruction project, which was completed in 2000.

Upon being asked for his thoughts on becoming director, Tyson said "when I was a kid... there were scientists and educators on the staff at the Hayden Planetarium... who invested their time and energy in my enlightenment... and I've never forgotten that. And to end up back there as its director, I feel this deep sense of duty, that I serve in the same capacity for people who come through the facility today, that others served for me".

Tyson has written a number of popular books on astrophysics. In 1995, he began to write the "Universe" column for Natural History magazine. In a column he authored for a special edition of the magazine, called "City of Stars", in 2002, Tyson popularized the term "Manhattanhenge" to describe the two days annually on which the evening sun aligns with the street grid in Manhattan, making the sunset visible along unobstructed side streets.

He had coined the term in 1996, inspired by how the phenomenon recalls the sun's solstice alignment with the Stonehenge monument in England. Tyson's column also influenced his work as a professor with The Great Courses.

In 2001, U.S. President George W. Bush appointed Tyson to serve on the Commission on the Future of the United States Aerospace Industry and in 2004 to serve on the President's Commission on Implementation of United States Space Exploration Policy, the latter better known as the "Moon, Mars, and Beyond" commission. Soon afterward, he was awarded the NASA Distinguished Public Service Medal, the highest civilian honor bestowed by NASA.

​In 2004, Tyson hosted the four-part Origins miniseries of the PBS Nova series, and, with Donald Goldsmith, co-authored the companion volume for this series, Origins: Fourteen Billion Years Of Cosmic Evolution. He again collaborated with Goldsmith as the narrator on the documentary 400 Years of the Telescope, which premiered on PBS in April 2009.

As director of the Hayden Planetarium, Tyson bucked traditional thinking in order to keep Pluto from being referred to as the ninth planet in exhibits at the center. Tyson has explained that he wanted to look at commonalities between objects, grouping the terrestrial planets together, the gas giants together, and Pluto with like objects, and to get away from simply counting the planets.

He has stated on The Colbert Report, The Daily Show, and BBC Horizon that this decision has resulted in large amounts of hate mail, much of it from children. 

In 2006, the International Astronomical Union (IAU) confirmed this assessment by changing Pluto to the dwarf planet classification.

Tyson recounted the heated online debate on the Cambridge Conference Network (CCNet), a "widely read, UK-based Internet chat group", following Benny Peiser's renewed call for reclassification of Pluto's status. Peiser's entry, in which he posted articles from the AP and The Boston Globe, spawned from The New York Times's article entitled "Pluto's Not a Planet? Only in New York".

Tyson has been vice-president, president, and chairman of the board of the Planetary Society. He was also the host of the PBS program Nova ScienceNow until 2011. He attended and was a speaker at the Beyond Belief: Science, Religion, Reason and Survival symposium in November 2006. In 2007, Tyson was chosen to be a regular on The History Channel's popular series The Universe.

​In May 2009, Tyson launched a one-hour radio talk show called StarTalk, which he co-hosted with comedian Lynne Koplitz. The show was syndicated on Sunday afternoons on KTLK AM in Los Angeles and WHFS in Washington DC.

The show lasted for thirteen weeks, but was resurrected in December 2010 and then, co-hosted with comedians Chuck Nice and Leighann Lord instead of Koplitz. Guests range from colleagues in science to celebrities such as GZA, Wil Wheaton, Sarah Silverman, and Bill Maher. The show is available via the Internet through a live stream or in the form of a podcast.

In April 2011, Tyson was the keynote speaker at the 93rd International Convention of the Phi Theta Kappa International Honor Society of the Two-year School. He and James Randi delivered a lecture entitled Skepticism, which related directly with the convention's theme of The Democratization of Information: Power, Peril, and Promise.

In 2012, Tyson announced that he would appear in a YouTube series based on his radio show StarTalk. A premiere date for the show has not been announced, but it will be distributed on the Nerdist YouTube Channel. 

On February 28, 2014, Tyson was a celebrity guest at the White House Student Film Festival.

In 2014, Tyson helped revive Carl Sagan's Cosmos: A Personal Voyage television series, presenting Cosmos: A Spacetime Odyssey on both FOX and the National Geographic Channel. Thirteen episodes were aired in the first season, and Tyson has stated that if a second season were produced, he would pass the role of host to someone else in the science world. On March 9, 2020, Tyson returned with a follow-up season of Cosmos titled Cosmos: Possible Worlds.

On April 20, 2015, Tyson began hosting a late-night talk show entitled StarTalk on the National Geographic Channel, where Tyson interviews pop culture celebrities and asks them about their life experiences with science.

Tyson is co-developing a sandbox video game with Whatnot Entertainment, Neil deGrasse Tyson Presents: Space Odyssey, which aims to help provide players with a realistic simulation of developing a space-faring culture, incorporating educational materials about space and technology. The project got no new development updates since April 2020.


Views:

Spirituality

A most important feature is the analysis of the information that comes your way. And that's what I don't see enough of in this world. There's a level of gullibility that leaves people susceptible to being taken advantage of. I see science literacy as kind of a vaccine against charlatans who would try to exploit your ignorance.— Neil deGrasse Tyson, from a transcript of an interview by Roger Bingham on The Science Network.

​Tyson has written and broadcast extensively about his views of science, spirituality, and the spirituality of science, including the essays "The Perimeter of Ignorance" and "Holy Wars", both appearing in Natural History magazine and the 2006 Beyond Belief workshop.

In an interview with comedian Paul Mecurio, Tyson offered his definition of spirituality: "For me, when I say spiritual, I'm referring to a feeling you would have that connects you to the universe in a way that it may defy simple vocabulary. We think about the universe as an intellectual playground, which it surely is, but the moment you learn something that touches an emotion rather than just something intellectual, I would call that a spiritual encounter with the universe."

Tyson has argued that many great historical scientists' belief in intelligent design limited their scientific inquiries, to the detriment of the advance of scientific knowledge.

When asked during a question session at the University at Buffalo if he believed in a higher power, Tyson responded: "Every account of a higher power that I've seen described, of all religions that I've seen, include many statements with regard to the benevolence of that power. When I look at the universe and all the ways the universe wants to kill us, I find it hard to reconcile that with statements of beneficence."  

In an interview with Big Think, Tyson said, "So, what people are really after is what is my stance on religion or spirituality or God, and I would say if I find a word that came closest, it would be 'agnostic' ... at the end of the day I'd rather not be any category at all." 

Additionally, in the same interview with Big Think, Tyson mentioned that he edited Wikipedia's entry on him to include the fact that he is an agnostic: "I'm constantly claimed by atheists. I find this intriguing. In fact, on my Wiki page – I didn't create the Wiki page. Others did, and I'm flattered that people cared enough about my life to assemble it – and it said, "Neil deGrasse Tyson is an atheist." I said, "Well, that's not really true." I said, "Neil deGrasse Tyson is an agnostic."

I went back a week later. It said, "Neil deGrasse Tyson is an atheist" again – within a week! – and I said, "What's up with that?" and I said, "All right, I have to word it a little differently." So I said, "Okay, Neil deGrasse Tyson, widely claimed by atheists, is actually an agnostic."

During the interview "Called by the Universe: A Conversation with Neil deGrasse Tyson" in 2009, Tyson said: "I can't agree to the claims by atheists that I'm one of that community. I don't have the time, energy, interest of conducting myself that way... I'm not trying to convert people. I don't care."

​In March 2014, philosopher and secularism proponent Massimo Pigliucci asked Tyson: "What is it you think about God?" Tyson replied: "I remain unconvinced by any claims anyone has ever made about the existence or the power of a divine force operating in the universe."

Pigliucci then asked him why he expressed discomfort with the label "atheist" in his Big Think video. Tyson replied by reiterating his dislike for one-word labels, saying: "That's what adjectives are for. What kind of atheist are you? Are you an ardent atheist? Are you a passive atheist? An apathetic atheist? Do you rally, or do you just not even care? So I'd be on the 'I really don't care' side of that, if you had to find adjectives to put in front of the word 'atheist'."

Pigliucci contrasted Tyson with scientist Richard Dawkins: "[Dawkins] really does consider, at this point, himself to be an atheist activist. You very clearly made the point that you are not." Tyson replied: "I completely respect that activity. He's fulfilling a really important role out there."

Philosophy:

Tyson has spoken about philosophy on numerous occasions. In March 2014, during an episode of The Nerdist Podcast, he stated that philosophy is "useless" and that a philosophy major "can really mess you up", which was met with disapproval. The philosopher Massimo Pigliucci later criticized him for "dismiss[ing] philosophy as a useless enterprise".

Race and social justice:

In an undated interview at Howard Hughes Medical Institute, Tyson talked about being black and one of the most visible and well-known scientists in the world. He told a story about being interviewed about a plasma burst from the sun on a local Fox affiliate in 1989.

"I'd never before in my life seen an interview with a black person on television for expertise that had nothing to do with being black. And at that point, I realized that one of the last stereotypes that prevailed among people who carry stereotypes is that, sort of, black people are somehow dumb.

I wondered, maybe ... that's a way to undermine this sort of, this stereotype that prevailed about who's smart and who's dumb. I said to myself, 'I just have to be visible, or others like me, in that situation.' That would have a greater force on society than anything else I could imagine."

In 2005, at a conference at the National Academy of Sciences, Tyson responded to a question about whether genetic differences might keep women from working as scientists. He said that his goal to become an astrophysicist was "...hands down the path of most resistance through the forces ... of society".

He continued: "My life experience tells me, when you don't find blacks in the sciences, when you don't find women in the sciences, I know these forces are real and I had to survive them in order to get where I am today. So before we start talking about genetic differences, you gotta come up with a system where there's equal opportunity. Then we can start having that conversation."

In a 2014 interview with Grantland, Tyson said that he related his experience on that 2005 panel in an effort to make the point that the scientific question about genetic differences can not be answered until the social barriers are dismantled. "I'm saying before you even have that conversation, you have to be really sure that access to opportunity has been level."

In that same interview, Tyson said that race is not a part of the point he is trying to make in his career or with his life. According to Tyson, "[T]hat then becomes the point of people's understanding of me, rather than the astrophysics. So it's a failed educational step for that to be the case. If you end up being distracted by that and not [getting] the message."

He purposefully no longer speaks publicly about race. "I don't give talks on it. I don't even give Black History Month talks. I decline every single one of them. In fact, since 1993, I've declined every interview that has my being black as a premise of the interview."

NASA:
​
Tyson is an advocate for expanding the operations of the National Aeronautics and Space Administration. Arguing that "the most powerful agency on the dreams of a nation is currently underfunded to do what it needs to be doing". 

Tyson has suggested that the general public has a tendency to overestimate how much revenue is allocated to the space agency. At a March 2010 address, referencing the proportion of tax revenue spent on NASA, he stated, "By the way, how much does NASA cost? It's a half a penny on the dollar. Did you know that? The people are saying, 'Why are we spending money up there...' I ask them, 'How much do you think we're spending?' They say 'five cents, ten cents on a dollar.' It's a half a penny."

In March 2012, Tyson testified before the United States Senate Science Committee, stating that: "Right now, NASA's annual budget is half a penny on your tax dollar. For twice that—a penny on a dollar—we can transform the country from a sullen, dispirited nation, weary of economic struggle, to one where it has reclaimed its 20th century birthright to dream of tomorrow."

Inspired by Tyson's advocacy and remarks, Penny4NASA, a campaign of the Space Advocates nonprofit, was founded in 2012 by John Zeller and advocates the doubling of NASA's budget to one percent of the federal budget.

In his book Space Chronicles: Facing the Ultimate Frontier Tyson argues that large and ambitious space exploration projects, like getting humans to Mars, will probably require some sort of military or economic driver in order to get the appropriate funding from the United States federal government.


Media appearances:

​As a science communicator, Tyson regularly appears on television, radio, and various other media outlets. He has been a regular guest on The Colbert Report, and host Stephen Colbert refers to him in his comedic book I Am America (And So Can You!), noting in his chapter on scientists that most scientists are "decent, well-intentioned people", but, presumably tongue-in-cheek, that "Neil DeGrasse [sic] Tyson is an absolute monster." 

He has appeared numerous times on The Daily Show with Jon Stewart. He has made appearances on: 
He served as one of the central interviewees on the various episodes of the History Channel science program, The Universe. Tyson participated on the NPR radio quiz program Wait Wait... Don't Tell Me! in 2007 and 2015. 

He has appeared several times on Real Time with Bill Maher, and he was also featured on an episode of Who Wants to Be a Millionaire? as the ask-the-expert lifeline. 

He has spoken numerous times on the Philadelphia morning show, Preston and Steve, on 93.3 WMMR, as well as on SiriusXM's Ron and Fez and The Opie and Anthony Show.

Tyson has been featured as a podcast guest interviewee on:  and he has he been in several of the Symphony of Science videos.

Tyson lived near the World Trade Center and was an eyewitness to the September 11, 2001, attacks. He wrote a widely circulated letter on what he saw. Footage he filmed on the day was included in the 2008 documentary film 102 Minutes That Changed America.

In 2007, Tyson was the keynote speaker during the dedication ceremony of Deerfield Academy's new science center, the Koch Center in Massachusetts, named for David H. Koch '59. He emphasized the impact science will have on the twenty-first century, as well as explaining that investments into science may be costly, but their returns in the form of knowledge gained and piquing interest is invaluable.

Tyson has also appeared as the keynote speaker at The Amazing Meeting, a science and skepticism conference hosted by the James Randi Educational Foundation.

Tyson made a guest appearance as a version of himself in the episode "Brain Storm" of Stargate Atlantis alongside Bill Nye and in the episode "The Apology Insufficiency" of The Big Bang Theory. 

Archive footage of him is used in the film Europa Report. Tyson also made an appearance in an episode of Martha Speaks as himself.

​In a May 2011 StarTalk Radio show, The Political Science of the Daily Show, Tyson said he donates all income earned as a guest speaker.

Tyson is a frequent participant in the website Reddit's AMAs (Ask Me Anythings) where he is responsible for three of the top ten most popular AMAs of all time.

In Action Comics #14 (January 2013), which was published November 7, 2012, Tyson appears in the story, in which he determines that Superman's home planet, Krypton, orbited the red dwarf LHS 2520 in the constellation Corvus 27.1 lightyears from Earth.

Tyson assisted DC Comics in selecting a real-life star that would be an appropriate parent star to Krypton, and picked Corvus, which is Latin for "Crow", and which is the mascot of Superman's high school, the Smallville Crows. 

Tyson also had a minor appearance as himself in the 2016 film Batman v Superman: Dawn of Justice.

In May 2013, the Science Laureates of the United States Act of 2013 (H.R. 1891; 113th Congress) was introduced into Congress. Neil deGrasse Tyson was listed by at least two commentators as a possible nominee for the position of Science Laureate, if the act were to pass. 

On March 8, 2014, Tyson made a SXSW Interactive keynote presentation at the Austin Convention Center.

On June 3, 2014, Tyson co-reviewed Gravity in a CinemaSins episode. He made two more appearances with CinemaSins, co-reviewing Interstellar on September 29, 2015, and The Martian on March 31, 2016.

In 2016, Tyson narrated and was a script supervisor for the science documentary Food Evolution, directed by Academy Award–nominated director Scott Hamilton Kennedy. In the same year, Tyson made a guest appearance on the Avenged Sevenfold album The Stage, where he delivered a monolog on the track "Exist". 

In 2017, Tyson appeared on Logic's album Everybody as God, uncredited on various tracks, and credited on the song "AfricAryaN" as well as on "The Moon" on Musiq Soulchild's album Feel the Real.

In 2018, Tyson made a second guest appearance on The Big Bang Theory as himself, together with fellow television personality Bill Nye, in the first episode of the show's final season ("The Conjugal Configuration").

He also had guest appearances in the following: 

Personal life:

Tyson lives in the Tribeca neighborhood of Lower Manhattan with his wife, Alice Young. They have two children: Miranda and Travis. Tyson met his wife in a physics class at the University of Texas at Austin. They married in 1988 and named their first child Miranda, after the smallest of Uranus' five major moons. 

Tyson is a wine enthusiast whose collection was featured in the May 2000 issue of the Wine Spectator and the Spring 2005 issue of The World of Fine Wine.

Sexual misconduct allegations:

During November and December 2018, accusations of sexual misconduct were made against Tyson by four women: 
  • Thchiya Amet El Maat accused Tyson of drugging and raping her while both were graduate students at UT Austin in 1984. 
  • Katelyn Allers, a professor at Bucknell University, alleged Tyson touched her inappropriately at a 2009 American Astronomical Society gathering. 
  • Ashley Watson, Tyson's assistant on Cosmos, alleged Tyson made inappropriate sexual advances to her in 2018 which led her to resign from the position days later. In what Tyson described as a Native American handshake, he held her hand and looked her in the eye for ten seconds. When she left, he told her he wanted to hug her but would rather not in case he wanted more. 
  • A fourth anonymous woman alleged Tyson made inappropriate comments to her during a 2010 holiday party at the American Museum of Natural History. 

Tyson denied El Maat's rape accusation, while corroborating the basic facts around the situation of Allers and Watson's assertions, but claimed his actions were misinterpreted and apologized for any misunderstanding or offense.

Fox, National Geographic, the Museum of Natural History, and the producers of Cosmos announced investigations, which Tyson stated that he welcomed. The National Geographic Channel announced on January 3, 2019, that they were putting further episodes of StarTalk on hiatus so as "to allow the investigation to occur unimpeded". 

The premiere of Cosmos: Possible Worlds, initially scheduled for March 3, 2019, was also delayed while the investigation continued. 

On March 15, 2019, both National Geographic and Fox announced that: "The investigation is complete, and we are moving forward with both StarTalk and Cosmos," and that: "There will be no further comment."

The networks affirmed that both StarTalk and Cosmos would resume, but that no date had been set. 

In July, the American Museum of Natural History stated Neil deGrasse Tyson would keep his job as director of the Hayden Planetarium.

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