The Space Age Astronomy in the Time of Rockets, Satellites and Space Telescopes

The most commonly accepted date for the beginning of the space age is October 4, 1957, the launch date of the first artificial satellite Sputnik 1. We start this section a little bit earlier to give credit to rocket pioneers like Konstantin Tsiolkovsky, Robert Esnault-Pelterie, Hermann Oberth, Robert H. Goddard, Wernher von Braun and Sergei Korolev. Chronologically, there is an overlap with our Standards and Measurements section as we moved early progress in rocketry into the Space Age section while leaving developments in astronomy and astrophysics prior to 1957 in the Standards and Measurements section. This site tries to provide a broad spectrum of historical events in the fields of astronomy, astrophysics and astronautics. There is not enough space to list all events relevant to the advances of space travel. For a comprehensive list of all pioneering events in the fields of rockets, satellites and space crafts, check our out Spaceflight Firsts site. One of the most important inventions of the 20th century was the computer, allowing scientists to store more data than a single person could collect in a lifetime, culmination in a star catalogue registering 1.7 Billion (!) stars - a long way from the 1,022 stars Ptolemy counted two millennia ago. The primary focus of this site is not astronomy, but Star Lore, which is folklore based upon stars and star patterns. We try to create a collection of mythical stories about stars and constellations from all over the world. However, to better understand the myths and legends of stars and constellations, a brief history of the development of our modern constellations might be helpful. This is by no means a scientific paper on the history of astronomy, but merely an illustrated collection of highlights of that history, along with some links to what we think are reliable sources on the subject.

Bits of the History of Astronomy since the Beginning of the Space Age

The Rocket Equation (1897) Russian rocket scientist Konstantin Tsiolkovsky systematically studied the theory of motion of rocket apparatus and discovered that a rocket, unlike other forms of propulsion, will work in a vacuum. In 1897, Tsiolkovsky derived the the "formula of aviation," now known as the Tsiolkovsky rocket equation, describing the motion of vehicles that follow the basic principle of a rocket. Source: Wikipedia

Tsiolkovsky's Rocket Concept Smithsonian Air and Space Museum

The Exploration of Cosmic Space by Means of Reaction Devices (1903) In 1903, Tsiolkovsky published his most important work, Исследование мировых пространств реактивными приборами (Exploration of Outer Space by Means of Rocket Devices). In it, Tsiolkovsky correctly calculated the horizontal speed required for a minimal orbit around the Earth as 8,000 m/s (5 miles per second) and reasoned, that this speed could be achieved by means of a multistage rocket fueled by liquid oxygen and liquid hydrogen. Source: Wikipedia

Exploration of Outer Space Source: web.archive.org

The Unlimited Lightening of Engines (1913) In 1912, French aircraft designer and spaceflight theorist Robert Esnault-Pelterie delivered a lecture on The unlimited lightening of engines, which was the first European work outside Russia to demonstrate theoretically that space travel was possible. In 1913, his lecture was published under the title Considérations sur les résultats d’un allégement indéfini des moteurs. Independently from Tsiolkovsky, Esnault-Pelterie developed the same theoretical foundations and arrived at the same Rocket Equation and the same escape velocity as Tsiolkovsky, whose work at the time was not yet translated. Esnault-Pelterie's culminating work L'Astronautique was published in 1930. A later edition in 1934 included applications of nuclear power. Sources: Wikipedia, historyofinformation.com

The Unlimited Lightening of Engines; Christie's

A Method of Reaching Extreme Altitudes (1919) In 1919, US-American engineer Robert H. Goddard published the monograph A Method of Reaching Extreme Altitudes, describing his mathematical theories of rocket flight. Goddard was not aware of the research of Russian engineer Tsiolkovsky and came independently to the same results. On January 13, 1920, The New York Times personally attacked Goddard and ridiculed his ideas: That Professor Goddard ... does not know the relation of action and reaction, and of the need to have something better than a vacuum against which to react — to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools. 43 years later, the New York Times admitted, that is was wrong (see below). Sources: Wikipedia, astronauticsnow.com

A Method of Reaching Extreme Altitudes Source: goodreads.com

The Rocket into Planetary Space (1923) In 1919, German physicist and engineer Hermann Oberth enrolled as a postgraduate student at the University of Göttingen. In 1922, he presented a doctoral dissertation on rocket science - the senior professors at his university rejected it as "utopian". In response, Obert first presented his study to the University of Cluj in Romania (which accepted it) and then published his work privately under the title Die Rakete zu den Planetenräumen (The Rocket into Planetary Space). By 1929, the original 92-page paper had grown to a 429-page book titled Ways to Spaceflight (Wege zur Raumschiffahrt in German). Among other groundbreaking ideas, the book contained the first concept of a multi-staged liquid fueled rocket. Sources: Wikipedia, Erna Roth-Oberth: Herman Oberth - A Bridge across Time

Die Rakete zu den Planetenräumen Source: Weltraumladen

Tsiolkovsky, Esnault-Pelterie, Goddard and Oberth are considered the most influential rocket pioneers of the early 20th century. To a large extend, they were unaware of each other's early works. All four arrived independently at the same concepts and formulas and soon, their ideas would become reality.

Liftoff! (1926) On March 16, 1926, Robert H. Goddard launched "Nell", the world's first liquid-fueled rocket, reaching an altitude of 41 feet. In 1919, the New York Times (see above) ridiculed Goddard's rocket concept. 43 years later, one day after the Apollo 11 moon landing, the New York Times wrote: Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error. Sources: Wikipedia, astronauticsnow.com

Goddard and "Nell"; Source: Wikipedia

Raketenflugpost (1931) On February 216, 1931, Austrian rocket pioneer Friedrich Schmiedl launched a rocket from the Austrian village Schöckl. The rocket contained 102 letters, that were delivered via parachute to the village St Radegund, two miles away. His Raketenflugpost (Rocket Air Mail) was the first commercial use of a rocket. In the following months, Schmidl conducted more launches (the letter shown below was postmarked August 23, 1932 / "Mail Rocket 13"). He had planned a commercial rocket mail service between Austria and Switzerland but the political climate of the time put a hold to his plans. In 1938, when Nazi-Germany occupied Austria, Schmiedl destroyed his entire research. Even before his mail rockets, Schmiedl was recognized as one of the leading rocket engineers of his time. In 1927, he received an invitation from the Japanese government to explore the military applications of rocketry. A similar offer was made by the US after the end of World War II - the pacifist Schmiedl declined both offers. Source: Wikipedia, Die Raketenflugpost des Ingenieur Schmiedl

Smiedl and one of his mail rockets Source: >austroclassic.at

An early Start to the Space Race (1933) Throughout the 1950s and 1960s, the USA and the Soviet Union were locked in a Space Race, competing for the first intercontinental rocket, the first satellite, the first astronaut and - eventually - the first step on the moon. In 1926 (see above), Robert H. Goddard launched the world's first liquid-fueled rocket. Five years later, rocketry amateurs in the Soviet Union founded GIRD, the Group for the Study of Reactive Motion (Группа изучения реактивного движения, Gruppa Izucheniya Reaktivnogo Dvizheniya in Russian) On August 17, 1933, the group launched GIRD-9, the Soviet Union's first rocket. It reached an altitude of 1,300 ft (400 m). However, Gird-9 was not yet a liquid fueled rocket. It used solidified benzene and liquid oxygen. GIRD-X, the Soviet Union's first liquid fuel rocket was launched on November 25, 1933, reaching an altitude of 262 ft (80m). Sources: Russian Space Web, Astronautix

GIRD Members with GIRD-X rocket; Sergey Korolev, "father" of the Soviet space program at far left Source: Smithsonian National Air and Space Museum

The first Step into Space (1944) In 1939, German rocket engineer Wernher von Braun started working on the first rocket able to reach outer space (later defined as the Kármán line, 100 km or 62 miles above seal level). First and foremost, the Aggregat 4 (A4) rocket (better known by its military propaganda name V-2, meaning Vergeltung, vengance) was designed as a weapon - the world's first long-range guided ballistic missile. On May 26, 1943, at its 26th test launch, the V-2 became the world's first functional long-range guided ballistic missile. In its military application, the rocket was launched in an angle, giving it a range of 200 miles (310 km) and an altitude of 55 miles (88 km). To see how the rocket's components worked in vacuum and zero gravity, it was launched vertically for a number of test flights. On June 20, 1944, during test 48, after a vertical launch, the rocket reached an altitude of 108.5 miles (174,6 km) on a ballistic trajectory, becoming the world's first object to reach outer space. At the end of World War II, the USA and the Soviet Union captured a number of rockets. After the war, V-2 engineers worked in the USA (led by von Braun) and in the Soviet Union (led by Helmut Gröttrup).

V-2 launch in 1943 Source: Wikipedia

Not only early US-American and Soviet rockets were based on the V-2 design. The first West-European rocket was a successor to the V-2 and the first Chinese missile was a licensed copy of an early Soviet rocket. Thus, the space programs of today's leading space powers Russia, USA, ESA and China all trace back to the same World War II weapon. Source: Wikipedia

The first Satellites (1957-1958) On August 21, 1957, the Soviet R-7 became the first successfully launched Intercontinental Ballistic Missile. On October 4, 1957, 19:28:34 UTC, a modified R-7 carried the world's first artificial satellite, Sputnik 1, opening the gates to a new world of research and science (and - unfortunately - a new world of warfare). Within the next six month, three more satellites followed. As everything was new, each of those satellites delivered a number of world's first. Sputnik 2, launched on November 3, 1957 carried the first animal, the dog Laika. Although Laika only lived for about five hours, the flight demonstrated that earth orbit is survivable for living beings. Explorer 1, the first US-American satellite, launched on February 1, 1958, was the first satellite equipped with scientific instruments. It delivered the first big discovery of the space age: the Van Allen Radiation Belt. The second US satellite, Vanguard 1, launched on March 17, 1958, was the first satellite to demonstrate that solar cells can supply the energy a space craft needs in orbit.

Sputnik 1 Source: Wikipedia Explorer 1 Source: Wikipedia

Laika Source: Wikipedia Vanguard 1 Source: Wikipedia

Source: Wikipedia - 1957 in spaceflight, 1958 in spaceflight

The Palomar Sky Survey (1958) Funded by the National Geographic Society, the Palomar Observatory Sky Survey was a major astronomical survey carried out at the Palomar Observatory. Using the Samuel Oschin Telescope, which is equipped with a Schmidt Camera providing wide fields of view with limited aberrations, 1,872 14-inch square photographic plates ware taken and published shortly after the last image was taken on December 10, 1958. The camera's resolution allowed photographs of stars up to a 22 magnitude.

Samuel Oschin Telescope; Wikipedia

In the 1960s, using the plates from the Palomar Sky Survey, Swiss astronomer Fritz Zwicky identified 31,350 galaxies and 9,700 clusters and published them separately in the Catalogue of Galaxies and of Clusters of Galaxies (see below). In the 1980s and 1990s, a new survey was conducted and in 1994, all of the original plates were digitized an published on 102 CD-ROMs as the Digitized Sky Survey. In 2001, the Minnesota Automated Plate Scanner identified over 89 million individual objects on the original plates and published their coordinates on 4 CD-ROMs. Sources: Wikipedia, Skyserver, Astronomical Catalogs, Charts, and Surveys

First Human Spaceflight (1961) On April 12, 1961, 06:07 UTC, the Soviet spacecraft Vostok 1 carried cosmonaut Yuri Gagarin into earth orbit. Gagarin was the fist human to see our planet from outer space. In his description of a beautiful and vulnerable Earth, he coined the term Blue Planet. As of year end 2020, a total of 567 people from 41 countries had a chance to follow Gagarin. Humanity now has over 20 years of uninterrupted presence in earth orbit. Source: Wikipedia

Ukrainian stamp commemorating the 50th anniversary of Gagarin's flight Source: Wikipedia

The Beginning of Space Gamma-Ray Astronomy (1961) NASA's satellite Explorer 11 carried the first Gamma-Ray telescope into earth orbit. During its seven-month lifespan, the satellite detected twenty-two events from gamma-rays and approximately 22,000 events from cosmic radiation. Although the instrument on board was called a Gamma-Ray-Telescope, it could only quantify gamma radiation but could not pinpoint its source, which is why credit for the "First Space Telescope" is usually given to NASA's OAO 2. Sources: Wikipedia, Andrew LePage

Positioning Explorer 11 in orbit Source: Scientific Satellites

Zwicky Galaxies (1961 - 1968) For over 50 years, Swiss astronomer Fritz Zwicky hunted supernovae, finding 120 of them. Zwicky examined 31,350 galaxies and 9,700 clusters recorded on plates of the Palomar Observatory Sky Survey (see above). In addition to his supernova studies, Zwicky put together the Catalogue of Galaxies and of Clusters of Galaxies. Today, the compact galaxies identified in the Catalogue are often called Zwicky galaxies. Source: Astronomical Catalogs, Charts, and Surveys

Zwicky Catalogue Source: amazon.com

A Quasar Three Billion Light Years Away (1963) In the 1950s, radio astronomers detected a number of unexplained objects. They emitted large amounts of radiation of many frequencies and the sources of these signal seemed to have been far away galaxies. By the 1960s, the third edition of the Cambridge Catalogue of Radio Sources listed hundreds of such sources, called QSOs (Quasi Stellar Objects). The abbreviation later morphed into today's term Quasar. In 1960, US-American astronomers Allan Sandage and Thomas A. Matthews were the first to link one of such sources - 3C 48 - with a stellar object, a faint blue star in the constellation Triangulum. But the nature of the source was still undetermined. In 1963, Dutch Astronomer Maarten Schmidt, using the Hale Telescope, was able to link radio source 3C 273 to the center of a giant elliptical galaxy with an apparent magnitude of 16 in the constellation Virgo. Schmidt correctly interpreted the visual spectrum of the source as spectral lines of hydrogen redshifted by 15.8%. Applying Hubble's Law and his theory of an expanding universe, Schmidt's observation implied a very far, very fast moving object. The large distance would mean that the object was far more luminous than any galaxy, but much more compact. We know now, that 3C 273 is over 4 trillion times more luminous than the Sun at visible wavelengths and is 2.443 billion light-years away. At the time of its discovery, it was the furthest known object in the then-known universe.

Visible light image of 3C 273 taken by the Hubble Space Telescope Source Wikipedia X-Ray image of 3C 273 Chandra X-ray Observatory Source: Wikipedia

In 1964, Austrian–born astrophysicist Edwin Ernest Salpeter and Soviet physicist Yakov Zeldovich developed a possible explanation for the all of these seemingly impossible characteristics by interpreting quasars as matter in an accretion disc falling into a supermassive black hole. The black hole associated with 3C 273 has been measured to a mass equal to roughly 900 million solar masses. Today, the Sloan Digital Sky Survey lists over half a million quasars. Sources: Wikipedia, Matthews, Sandage: Optical Identification of 3C 48, 3C 196, and 3C 286 with Stellar Objects, T. Courvoisier: Bright Quasar 3C 273, universeguide.com, pages.astronomy.ua.edu

The Arecibo Observatory (1963) Originally designed as part of an Anti ballistic missile defense system, the Arecibo Observatory in Puerto Rico became famous for its research in radio astronomy, atmospheric science, and radar astronomy. The observatory was instrumental in the discovery of one of the first Pulsars in 1967 and was the site of the discovery of the first exoplanets in 1995. The 1,000 ft (305 m) spherical reflector dish was built into a natural sinkhole. From its dedication in 1963 until the completion of the FAST Telescope in China in 2016, it was the world's largest single-aperture radio telescope. Source: Wikipedia,

Arecibo Observatory Source: Wikipedia

The Sounds of the Big Bang (1964) In 1948, US-American cosmologists Ralph A. Alpher and Robert Herman introduced the hypothesis that a remnant from an early stage of the universe in form of electromagnetic radiation could still be detected today. In the early 1960's Soviet physicist Yakov Zeldovich and US-American astronomer Robert H. Dicke independently came to the same conclusion. In 1964, at Princeton University, Dicke, together with astrophysicists Jim Peebles and David Wilkinson hypothesized that the Big Bang should have produced a huge burst of radiation which - after traveling for over 13 billion years would be red-shifted to very long wavelengths and would probably appear as radio waves. They started actively searching for what was now called the Cosmic Microwave Background. At the same time, only 37 miles away, at Bell Labs in Holmdel, New Jersey - the place where Karl Guthe Jansky in 1931 discovered radio waves coming from the center of the Milky Way (see here) - physicists Arno Penzias and Robert Wilson were trying to measure the radio waves emanating from galaxies beyond our own Milky Way.

Cosmic Microwave Background recorded by the COBE satellite Source: universetoday.com Bell Labs Horn Antenna Source: Wikipedia

Using a highly sensitive horn antenna, Penzias and Wilson encountered a lot of static in their signal. After removing all possible sources of interference, they still noticed a persistent noisy hum that seemed to come from everywhere. When Penzias and Wilson contacted Dicke, they realized that they just had discovered the signal, the Princeton team had been looking for. Both teams agreed to publish their findings simultaneously in separate papers. Penzias and Wilson received the 1978 Nobel Prize for Physics. Of the Princeton team, only Jim Peebles lived long enough to receive similar honors. He was awarded the 2019 Nobel Prize for Physics "for theoretical discoveries in physical cosmology." In 1989, the Cosmic Background Explorer continued the research of the cosmic microwave background. Sources: Wikipedia, universetoday.com, discovermagazine.com

A Starship navigating by the Stars (1965) On July 15, 1965, NASA's space probe Mariner 4 delivered the first closeup pictures of Mars. On its voyage to Mars, NASA used the Sun and the star Canopus to stabilize the spacecraft on two axis. It was the fist time a star had been used in the navigation of an unmanned space probe. Source: Wikipedia

Artist's concept of Mariner 4 Source: youtube.com

The Smithsonian Astrophysical Observatory Star Catalog (1966) In 1966, the Smithsonian Astrophysical Observatory published a catalogue containing 258,997 stars down to a magnitude of 9. The cataloge was a compilation of various previous astrometric catalogues. In 1983, it became part of the Catalog of Stellar Identifications (see below). Source: Wikipedia

Smithsonian Astrophysical Observatory Star Catalog Source: amazon.com

Pulsars and Little Green Men (1967/1968) In 1967, English radio astronomer Antony Hewish and Northern Irish graduate student Jocelyn Bell Burnell at the University of Cambridge discovered a radio source consisting of pulses separated by 1.33 seconds. At the time of discovery, a number of explanations were discussed, including a radio signal from another inhabited world, which is why the discoveres initially nicknamed the signal LGM-1 - LGM meaning "Little Green Men." (Today, this pulsar's designation is more prosaic: PSR J1921+2153 In search of an explanation within the realms of astrophysics, scientists went back to the the hypothesis of neutron stars, developed by Fritz Zwicky and Walter Baade.

Crab Nebula Pulsar Source: Wikipedia

Just befor the discovery of the first pulsar, Italian physicist Franco Pacini suggested that a rotating neutron star with a magnetic field would emit radiation. Shortly after the discovery of the pulsar, Austrian-American astrophysicist Thomas Gold independently came to the same conclusion. Pacini suggested that a radio source fitting his model could be a rotating neutron star in the Crab Nebula, which is the remnant of the 1054 Supernova. The idea was first me with scepticism, but then, in 1968, a team at the Arecibo Observatory confirmed the period and location of the Crab Nebula Pulsar - just as predicted. Source: Wikipedia

Stargazer - The First Space Telescope (1968) On December 7, 1968 astronomy left the confinement of Earth and the interferrence of Earth's atmosphere. OAO 2, the Orbiting Astronomical Observatory, nicknamed Stargazer was launched into an almost circular orbit, 480 miles (770 km) above Earth. After the failed mission of OAO 1 in 1966, the Stargazer was the first functioning space telescope. It carried fiveteen different telescopes, all designed for ultraviolet observations. The world's first space telescope was operational for four years until January 1973. Sources: Wikipedia, University of Wisconsin

Artist's concept of OAO 2 Source: University of Wisconsin

Earthrise (1968) In December 1968, US-American Apollo 8 became the first manned spacecraft to leave Earth orbit and to go further than any human had gone before. Frank Borman, Jim Lovell and Bill Anders were the first humans to see our home planet in its entirety, floating in space. In the morning of December 24, 1968, the craft entered Lunar orbit and on Christmas Eve, Bill Anders took a picture that is now considered the most iconic image of human spaceflight and the most influential environmental photograph ever taken. Source: Wikipedia

Earthrise Source: Wikipedia

One Giant Leap (1969) On July 20, 1969, 20:17:40 UTC, the Eagle, the lunar module of Apollo 11 touched down in the Sea of Tranquility. On July 21 at 02:56:15, astronaut Neil Armstrong, followed by Buzz Aldrin became the first human to set foot on a celestial body other than Earth. Throughout the next three years, NASA carried out a total of six successful moon landings and twelve men walked the surface of our closest neighbor. Source: Wikipedia

Buzz Aldrin on the Lunar surface Source: National Public Radio

Project Blue Book (1969) One of the side effects of the popularity of early human space flights was a hype about extraterrestrial life, resulting in thousands of so-called UFO sightings (UFO standing for unidentified flying object). This site has no opinion on these speculations and neither supports nor opposes any ideas about extraterrestrial life. But we'd like to point out that the US Air Force took the reports seriously enough to investigate them starting in 1947 - and didn't find a single alien. In 1968, after examining hundreds of UFO files from the Air Force's Project Blue Book and from civilian UFO groups, the Condon Committee at the University of Colorado concluded, that "the study of UFOs was unlikely to yield major scientific discoveries."

Project Blue Book amazon.com

Condon Report amazon.com

As a result of the Condon Report, the US Air Force terminated its UFO project in December 1969. Project Blue Book examined a total of 12,618 reported sightings. 701 of those sightings remained "unidentified", all others had an explanation unrelated to extraterrestrial activities. Project Bue Book came to the following conclusions: No UFO reported, investigated, and evaluated by the Air Force was ever an indication of threat to our national security. There was no evidence submitted to or discovered by the Air Force that sightings categorized as "unidentified" represented technological developments or principles beyond the range of modern scientific knowledge. There was no evidence indicating that sightings categorized as "unidentified" were extraterrestrial vehicles. In 2019, the history of Project Blue Book became a historical drama television series. Sources: Wikipedia, US Air Force Fact Sheet

Uhuru - the first X-Ray Space Observatory (1970) Over the course of two and a half years, starting with its launch on December 12, 1970, the Uhuru X-ray observatory performed the first comprehensive survey of the entire sky for X-ray sources. The Uhuru Catalogue lists 339 objects covering the whole sky. The satellite was launched from the San Marco platform, a launch platform near the equator off the coast of Kenya. It was named Uhuru ( Swahili for freedom) in recognition of Kenya's hospitality. Source: Wikipedia

Artist's concept of Uhuru Source: NASA

CSI and SIMBAD (1971-2006) In an attempt to consolidate the growing number of star catalogues, the Strasbourg Astronomical Data Center (Centre de données astronomiques de Strasbourg in French) created the Catalog of Stellar Identifications, which contained stellar coordinates, magnitudes, spectral types, proper motions, and cross-references to designations in previously catalogs for aproximately 450,000 objects. In 1971, the catalogue merged the following older catalogues: Astronomische Gesellschaft Katalog of 1890 and its extensions of 1892 and 1900 for the southern hemisphere Henry Draper Catalogue of 1918 Yale Bright Star Catalogue of 1930 Boss General Catalogue of 1936 Smithsonian Astrophysical Observatory Star Catalog of 1966

Strasbourg Observatory; Wikipedia

In 1979, the CSI was moved from the Meudon Computer Centre to the mainframe of Strasburg University and became SIMBAD, the Set of Identifications, Measurements and Bibliography for Astronomical Data. The move was completed in 1981; this version was called SIMBAD II. Two major upgrades took place in 1990 (SIMBAD III) and 2006 (SIMBAD IV). Today, SIMBAD is a constantly updated dynamic database, providing all available basic information on over 11.5 million objects outside ouf our Solar System. Sources: SIMBAD Homepage, M. Wenger et al.: the SIMBAD Database, published at Harvard University.

Black Hole Cygnus X-1 (1972) As predicted by English natural philosopher John Michell as early as 1783 a Black Hole can be detected by its effects on other stars. Radio source Cygnus X-1, one of the strongest X-ray sources observed from Earth was detected in 1964 during a suborbital rocket flight. In 1970, English astronomer Paul Murdin and Australian astronomer Louise Webster at the Royal Greenwich Observatory identified the white supergiant star HDE 226868 as coinciding with with the X-ray source and resoned that it could be a binary star, possibly with one of the pair being the X-ray source, but - as predicted by John Michell - not being visible.

Artist's concept of HDE 226868 and Cygnus X-1 Source: ESA's Hubble Space Telescope Homepage

In January 1972, Murdin and Webster published an article entitled Cygnus X-1 - a Spectroscopic Binary with a Heavy Companion? in the journal Nature, suggesting that the "heavy companion" might indeed be a black hole.

At the same time - independently from Murdin's and Webster's observations - astronomer Tom Bolton at the David Dunlap Observatory in Toronto, Canada observed HDE 226868 wobble as if it were orbiting around an invisible but massive companion emitting powerful X-rays. By 1973, the astronomical community generally recognized Cygnus X-1 as the first confirmed Black Hole. Source: Wikipedia

Message in a Bottle - Pioneer 10 and 11 (1972-1973) On March 2, 1972 and April 6, 1973, NASA launched the space probes Pioneer 10 and Pioneer 11 to perform the first flybys of planets Jupiter and Saturn, respectively. The probes were the first objects launched with an escape velocity high enough to eventually leave the Solar System and enter interstellar space. As suggested by US-American astronomer and educator Carl Sagan, both probes carried messages to any potential allien civilization that might find them. The messages were plaques with drawings of humans and a graphical descriptions of the Solar System.

Pioneer Plaque; Wikipedia

In the late 1990s, the probes were passed by the faster Voyager probes which became the first human-built objects to enter interstellar space. The last signals from the Pioneer probes were received on September 30, 1995 (Pioneer 11) and January 23, 2003 (Pioneer 10). Both probes are currently approaching the Heliopause, the final frontier of the Solar System. Sources: Wikipedia - Pioneer 10, Wikipedia - Pioneer 11

Большой Телескоп - Bolshoi Teleskop (1975) For 28 years, California's Hale Telescope, was the largest telescope on Earth. In 1975 the Большой Телескоп Альт-азимутальный, the Large Altazimuth Telescope and its 6 meter (238 inches) reflector took the record to the Russian part of the Caucasus Mountains. Due to a number of technical difficulties, the telescope, officially named BAT-6, never lived up to its full potential but nevertheless, for seventeen years, it was the world's largest telescope. Source: Wikipedia

BAT-6; Wikipedia

The First International Space Flight (1975) On July 17, 1975, in the midst of the Cold War, US Air Force General Thomas P. Stafford and Soviet Air Force Commander Alexei Leonov shook hands in space. The Apollo–Soyuz Test Project, the docking of Soviet Soyuz and a US-American Apollo space craft was the first international space flight and as such the first stepping stone towards an International Space Station. Source: Wikipedia

Artist's concept of Apollo-Soyuz © NASA / Robert McCall

Putting Einstein to the Test (1976; 2004) In 1976 and 2004, respectively, NASA launched two satellites to test four still unverified predictions of general relativity. Gravity Probe A, launched in 1976, tested the equivalence principle and the concept of time dilation. Gravity Probe B, launched in 2004, tested the geodetic effect and frame dragging. The two probes confirmed all four theories within an expected margin of error.

Artist concept of Gravity Probe B measuring space-time; NASA

Like most of Einstein's ideas, these concepts are hard to understand and even harder to explain. Click on the links above to learn more about them. Sources: Wikipedia: Gravity Probe A, Wikipedia: Gravity Probe B

NASA's Great Observatories Plan (1979) As early as 1949, US-American astronomer Lyman Spitzer suggested astronomical observatories in Earth orbit in a paper entitled Astronomical advantages of an extraterrestrial observatory. Following the success of the OAO series, in 1979, the report A Strategy for Space Astronomy and Astrophysics for the 1980s by the National Research Council laid the groundwork for a series of four large satellites, called the Great Observatories in Earth orbit, complementing each other by covering different part of the spectrum.

NASA's Great Observatories Source: NASA

The Earth's atmosphere blurs visible light and prevents x-rays, gamma-rays and far-infrared radiation from reaching the ground. Thus all four observatories would be able to observe the universe in a way that is not possible with ground based instruments. First of the Great Observatories was the Hubble Space Telescope, operating in visible light and near-ultraviolet. It was launched in 1990 and is still operational. The Compton Gamma Ray Observatory was launched in 1991 and was operational until 2000. The Chandra X-ray Observatory, launched in 1999 is still operational. The Spitzer Space Telescope, investigation the infrared spectrum, was launched in 2003 and was in service until January 2020. Source: Wikipedia

IRAS - the First Infrared Space Observatory (1983) Observing the infrared spectrum allows astronomers to detect galaxies and nebulae that are moving so fast that they have redshifted out of the range of visible light. In addition, infrared light is of lower energy than visible light thus cooler stars like brown dwarf can be detected in this spectrum. Launched on January 25, 1983, NASA's IRAS, the Infrared Astronomical Satellite performed a ten-months survey of the entire night sky at infrared wavelengths, observing over 250,000 infrared sources. Source: Wikipedia

Artist's conception of IRAS Source: Wikipedia

NASA/IPAC Extragalactic Database (1988) In 1988, US-American astronomers George Helou and Barry F. Madore created an Extragalactic Database. It is funded by NASA and operated by the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology. The database contains 206 million distinct astronomical objects, such as galaxies, quasars, radio, x-ray and infrared sources. Sources: Wikipedia, NED Homepage, G. Helou et al.: The NASA/IPAC Extragalactic Database

The Hipparcos Spacecraft and Catalogue (1989) On August 8, 1989, the European Space Agency launched the first space craft devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. Hipparcos was the first space telescope operating in the spectrum range of visible light. The probe was named after Greek astronomer Hipparcos, who in the second century BC created one of the first star catalogues, covering 850 stars. - the data from the satellite named after him resulted in 135 times that number. Processing the one trillion gigabit resulted in the biggest computation in the history of astronomy. The results, published in 1997, were used to create two star catalogues and a star atlas:

Hipparcos Spacecraft; Source: ESA

The Hipparcos Catalogue is a high-precision catalogue of more 118,218 stars, mostly down to magnitude 8. These were the most precise measurements of stellar data made to date. The Tycho Catalogue, an auxiliary star map with lesser but still unprecedented accuracy originally contained 1,058,332 stars. An update, the Tycho 2 Catalogue, listing 2,539,913 stars, which represents 99% of all stars down to magnitude 11 was published in 2000. The Millennium Star Atlas consists of 1548 charts and includes one million stars from the Hipparcos and Tycho-1 Catalogues - three times as many as in any previous all-sky atlas. It also includes a number of non-stellar objects: more than 8,000 galaxies, many bright and dark nebulae, many open and globular clusters and about 250 of the brightest quasars. Sources: Wikipedia, ESA, skyandtelescope.org, Astronomical Catalogs, Charts, and Surveys

Exploring the Cosmic Background (1989) COBE, the Cosmic Background Explorer took radio astronomy into Earth orbit. Launched on November 18, 1989, COBE was the first Microwave space telescope. The probe investigated the cosmic microwave background radiation and provided key pieces of evidence that supported the Big Bang theory of the universe. COBE investigators George F. Smoot and John C. Mather received the 2006 Nobel Prize in Physics for their work on the project which the Nobel Prize committee considered "the starting point for cosmology as a precision science." Source: Wikipedia

COBE's map of microwave background radiation in the 31.5 GHz band; Wikipedia

Hubble Space Telescope (1990) Launched on April 24, 1990 and named after US-American astronomer Edwin Hubble, the Hubble Space Telescope was the first of NASA's Great Observatories. Operating in light's visible spectrum, Hubble has revolutionized our understanding of the Universe in a way that can only be compared to Galileo Galilei pointing the first telescope at the stars. The Telescope has been in operation for over 30 years and has delivered thousands of images of objects as close as the Moon and as far way as galaxy GN-z11, 32 billion light-years away. Hubble's images became a part of pop-culture and brought astronomy into living rooms and class rooms to an extend not seen since the Apollo Moon Landings. The Hubble Space Telescope is the only one of the Great Observatories that was designed to be serviced by astronauts. Between 1993 and 2009, the telescope had been visited five times by Space Shuttle crews for repairs, services and upgrades. Source: Wikipedia To celebrate Hubble's 30th anniversary, Space.com issued a collection of the best Hubble Space Telescope images. Here is a small selection:

Hubble Space Telescope Source: Wikipedia Hubble Space Telescope and Space Shuttle Source: culttvmanshop.com

Veil Nebula

Crab Nebula

Sombrero Galaxy

Pillars of Creation

Necklace Nebula

Horsehead Nebula

Whirlpool Galaxy

Monkey Head Nebula

Butterfly Nebula

Click here to see all 61 images.

Compton Gamma Ray Observatory (1991) Named after US-American physicist and Nobel Prize laureate Arthur Compton, the Compton Gamma Ray Observatory was the second of NASA's Great Observatories. The observatory was operational from 1991 to 2000 and featured four main telescopes covering X-rays and gamma rays. Among other discoveries, it registered a total of 2,704 gamma-ray bursts throughout the universe. Source: Wikipedia, Science Photo Library

Compton's Gamma-Ray Burst map Source: Science Photo Library

The First Exoplanets (1992) In January 1990, while working at the Arecibo Observatory, Polish astronomer Aleksander Wolszczan discovered a pulsar 2,300 light-years from the Sun in the constellation Virgo. The object, officially listed as PSR B1257+12, was named Lich. On January 22, 1992, Aleksander Wolszczan and Canadian astronomer Dale Frail discovered two planets orbiting the pulsar. They were named Draugr and Poltergeist. A third planet, named Phobetor) was discovered in 1994 The discovery of Draugr and Poltergeist was the first confirmed discovery of a planet outside our own Solar System.

Artist's concept of a planet orbiting a quasar; Wikipedia

The journal Nature declared it one of 15 fundamental discoveries in the field of physics; Astronomy Magazine ranked it among the 25 Greatest Astronomical Findings of All Time. Source: Wikipedia

The Kuiper Belt (1992) Shortly after the discovery of Pluto in 1930, US-American astronomer Frederick C. Leonard hypothesized whether it was not likely that in Pluto there has come to light the first of a series of ultra-Neptunian bodies, the remaining members of which still await discovery.... In 1943, Leonard's theory was supported by British astronomer Kenneth Edgeworth who speculated that the outer region of the solar system, beyond the orbits of the planets, is occupied by a very large number of comparatively small bodies. Ironically, Dutch-American astronomer Gerard Kuiper, after whom the area is named, did not agree. He argued that any trans-Neptunian bodies that might have existed in the early solar system would have been flung out of the solar system by Pluto's gravity.

Kuiper Belt objects (blue dots) scale in astronomical units Wikipedia

Throughout the next decades, the idea became more popular. In 1987, US-American astronomers David Jewitt and Jane Luu started a systematic search for Plutp-like objects outside the orbit of Neptune. In 1988, the - at this time still hypothetical - region was called Kuiper Belt for the first time in computer simulation conducted by a team led by Canadian astrophysicist Scott Tremaine. On August 30, 1992, working on the University of Hawaii's 2.24 m telescope at Mauna Kea, Jewitt and Luu discovered the first trans-Netunian object outside the Pluto/Charon system. Officially registered as 1992 QB1, the object was later named Albion.

Six month later, Jewitt and Luu discovered another object, 1993 FW. The largest object discovered so far has been Eris, identified in 2005 on a photograph taken in 2003 at the Palomar Observatory. At the time of their discovery, both Albion and Eris were hailed as the "tenth planet" (similar to Ceres first being called a planet 200 years earlier). At the time of Eris's discovery there were almost 300 Kuiper-Belt-Objects, causing the International Astronomical Union to develop a more detailed definition of objects in the Solar System. By 2020, more than 2,000 Kuiper Belt Objects have been observed. Source: Wikipedia

Albion, observed by the European Southern Observatory Wikipedia

Eris, observed by the Hubble Space Telescope NASA

The Magnificent Seven (1992) In 1990, a US-American Delta II rocket launched ROSAT, a German X-ray telescope (which included instruments from the US and the UK). In 1992, the crew operating the satellite detected a neutron star in the constellation Corona Australis. It turned out that at a distance of about 400 light-years, RX J1856 was the closest neutron star to Earth yet discovered. Between 1992 and 1999, the ROSAT team discovered six other neutron stars with similar characteristics. All seven objects are relatively young (several hundred thousand years) and are relatively close to Earth (between 400 and 1,600 light-years). Informally, the seven neutron stars were named The Magnificent Seven, after the heroes in the 1960 movie. When another relatively near by neutron star, located in the constellation Ursa Minor was discovered in 2007, it was informally named Calvera, after the villain in the same movie. In our opinion, putting the heroes and villain of a classic film on a star map qualifies as modern star lore. Sources: Wikipedia, BBC News

Artist's concept of a Neutron Star; Source: Wikipedia ROSAT; Source: Wikipedia

E pur si muove (1992) In 1633, the Inquisition of the Roman Catholic Church found Galileo Galilei guilty of heresy and forced him to recant his theory that the Earth moves around the Sun. 359 years later, Pope John Paul II acknowledged that the Church was wrong in condemning Galileo and that the theologians who condemned Galileo did not recognize the formal distinction between the Bible and its interpretation. E pur si muove - all the same, it moves. Source: Wikipedia

Galileo's tomb at the Basilica di Santa Croce in Florence, Italy Source: Wikipedia

Hawaii's Ten-Meter Telescopes (1993) The W. M. Keck Observatory near the summit of Mauna Kea on the island of Hawaii is named after the W. M. Keck Foundation, the main benefactor of the telescopes. The observatory consists of two telescopes with 10 m (33 ft) aperture primary mirrors. At their completion in 1993 and 1996, respectively, they were the two largest telescopes in the world. The largest and most mechanically complex of the observatory HIRES, the High Resolution Echelle Spectrometer, which performs precise measurements in thousands of individual color channels.

Domes of the Keck Telescopes Source: Wikipedia

HIRES' spectral capabilities have resulted in many breakthrough discoveries, such as direct evidence for a model of the Big Bang theory. In addition, HIRES has detected more extrasolar planets than any other instrument in the world. Source: Wikipedia

The Trouble with Hubble is Over (1993) Shortly after the Hubble Space Telescope was put into orbit in 1990, it turned out that a problem with the primary mirror caused images to apear out of focus. It was up to the 1993 service mission, carried out by the crew of STS-61 in December 1993, to fix the problem. In five spacewalks, the crew installed the required corrective hardware and other upgrades. After the first images taken by the repaired telescope were released, Senator Barbara Mikulski, a long time champion of the Hubble and James Webb space telescopes famously announced, "The trouble with hubble is over." Source: Wikipedia

Hubble Service Mission Source: Wikipedia

Star Clusters, Nebulae, and Galaxies (1995) In 1781, French astronomer and comet hunter Charles Messier published a list of diffuse objects that were not comets, to help comet hunters to distinguish between permanent and transient visually diffuse objects. The list became known as the Messier Catalogue - the first list of objects beyond our galaxy. While revolutionary at the time, the Messier Catalogue was not compiled as a list of star clusters or nebulae and excluded many of the sky's brightest deep-sky objects. In 1995, amateur astronomer Patrick Moore Caldwell, co-founder and president of the Society for Popular Astronomy compiled a list of 109 star clusters, nebulae, and galaxies, designed specifically for observation by amateur astronomers.

Caldwell Catalogue Objects Source: Wikipedia

The Caldwell Catalogue is now considered a supplement to the Messier Catalogue. Source: Wikipedia

The Search for Earth 2.0 (1995) On October 6, 1995, Swiss astrophysicists Michel Mayor and Didier Queloz announced the discovery of an exoplanet orbiting a main-sequence star - Sun-like 51 Pegasi. The planet was discovered using the ELODIE spectrograph at the Observatoire de Haute-Provence in southeastern France. Within a week of the announcement, the planet was confirmed by another team using the Lick Observatory in California. In 2019, its discoverers were awarded the Nobel Price.

Artists concept of Dimidium orbiting 51 Pegasi Source: Wikipedia

Once astronomers realized that exoplanets around main sequence stars could be discovered with currently available technology, the hunt was on. Before the year 2000, another 36 exoplanets were discovered. By November 2020, the list has risen to 4,370 confirmed exoplanets in 3,230 systems, with 715 systems having more than one planet. The planet in orbit of 51 Pegasi received the official designation 51 Pegasi b. In December 2015, it was given the name Dimidium, which is Latin for 'half', referring to the planet's mass of at least half the mass of Jupiter. Source: Wikipedia

The darkest Part of the Sky - Hubble Deep Field (1995) Between December 18 and 28, 1995, the Wide Field and Planetary Camera 2 of the Hubble Space Telescope was pointed at a small region in the constellation Ursa Major - totally dark to the naked eye. After 342 separate exposures, a picture emerged, showing about 3,000 objects - almost all of them galaxies, some of which are among the youngest and most distant known. 3,000 Galaxies, each of them consisting of an average of 100 Million stars, revealed in a "dark" spot that represents one 24-millionth of the whole sky!

Hubble Deep Field; Source: Wikipedia

Following the great success of the original Hubble Deep Field, NASA conducted several follow-ups. The Hubble Deep Field South in September/October 1998 targeted an area in the constellation Tucan and delivered results similar to those of the original Deep Field. The Hubble Ultra-Deep Field, done between September 2003 and January 2004, is the deepest image of the universe to date. It contained over 10,000 objects, the majority of which were galaxies. The Hubble eXtreme Deep Field, released on September 25, 2012, presented a portion of space in the center of the Ultra Deep Field image, but with twice the exposure time. It contained approximately 5,500 galaxies, the oldest of which were 13.2 billion light-years away. Wikipedia provides a list of deep field images taken by Hubble and by other telescopes. Source: Wikipedia

Chandra - X-Ray Images of the Universe (1999) Launched on July 23, 1999 and named after Nobel Prize-winning Indian astrophysicist Subrahmanyan Chandrasekhar, the Chandra X-ray Observatory was the third of NASA's Great Observatories. X-rays, which are high-energy photons, cannot penetrate the Earth's atmosphere and can therefore be only observed from locations very high in the atmosphere or in space. X-rays are emitted by supernova remnants, neutron stars and other galactic sources. The Chandra Observatory has greatly advanced the field of X-ray astronomy and has delivered countless Discoveries.

X-ray image of supernova remnant Cassiopeia A Source: skyandtelescope.org

Initially given an expected lifetime of 5 years, Chandra is still active over 20 years after its launch. Source: Wikipedia

The Sloan Digital Sky Survey (2000) In 1998, the Apache Point Observatory, operated by New Mexico State University began a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope. The project, the Sloan Digital Sky Survey is named after it main contributor, the Alfred P. Sloan Foundation. The SDSS team makes its data available on the internet. The First data release, published in 2000 contained 53 million unique objects. With the latest (the 16th) data release, the number of objects in the survey has grown to almost a billion.

2.5-meter Sloan Foundation Telescope Source: Apache Point Observatory

In 2020 (see below), the SDSS team published the largest-ever 3D map of the universe. Sources: Wikipedia, SDSS Homepage

The International Space Station (2000) Construction of the International Space Station (ISS) began on November 20, 1998 with the launch of the first module. On October 31, 2000, Russian space craft Soyuz TM-31 took the first long-duration crew, two Russian Cosmonauts and one US-American astronaut to the ISS. Since the docking on November 2, 2000, the ISS has been permanently occupied and for over twenty years now, there has been an uninterrupted human presence in space.

International Space Station; Wikipedia

As of November 17, 2020, 241 people (some multiple times) from 19 countries have been on board the ISS. Source: Wikipedia

The Spitzer Space Telescope (2003) Launched on August 25, 2003, the Spitzer Space Telescope completed the set of NASA's four Great Observatories. The infrared telescope was named after US-American astronomer Lyman Spitzer, who suggested astronomical observatories as early as 1949. While the other three Great Observatories all operated from Earth orbit, Spitzer was placed in a heliocentric orbit, trailing Earth and slowly drifting away from it.

Infrared image of the Helix Nebula; NASA

Targeting "cold" sources in the infrared spectrum, engineers had to make sure that the observatory’s "body heat" did not interfere with the observation of relatively cold cosmic objects. Therefor, the primary mirror was made of beryllium and was cooled to 5.5 K (−268 °C; −450 °F), using 95 gallons (360 liters) of liquid helium, which lasted for almost six years until May 2009. Even after that, Spitzer still delivered results, targeting "warmer" objects, such as exoplanets. NASA's Jet Propulsion Laboratory has put together a list of 15 of Spitzer's Greatest Discoveries. Sources: Wikipedia, NASA

The Hitchhiker's Guide to the Galaxy (2003) In 1978, BBC aired the radio series The Hitchhiker's Guide to the Galaxy which soon reached cult status and led (among other publications) to five volumes of a best-selling book. Author Douglas Adams told a story of how in 1971 he was hitch hiking around Europe with a copy of the Hitch-hiker's Guide to Europe book: while lying drunk in a field near Innsbruck with a copy of the book and looking up at the stars, he thought it would be a good idea for someone to write a hitchhiker's guide to the galaxy as well. In 2003, SETI released what could be called the first edition to an interstellar travel guide book. Examining 17,129 nearby stars, using the Hipparcos Catalogue, SETI created a list of stars with a potential for habitable planets.

Potentially habitable planets; universetoday.com

The Catalog of Nearby Habitable Systems originally listed 55 planets suitable for complex life. The list keeps growing and now contains 60 stars. Sources: Wikipedia, University of Puerto Rico.

The World's Biggest Binoculars (2005) By some measure, the Large Binocular Telescope on top of Mount Graham in Arizona is the world's largest telescope, by other measures, it isn't. The LBT started operating in October 2005. It has two mirrors, each 8.4 meters (330 inch) wide. The centers of the mirrors are 14.4 m apart; when using both, the LBT has the same light-gathering ability as a 11.8 m (464 inch) wide single circular telescope, which would make it larger than Hawaii's Keck Telescopes and larger than the current largest single-aperture telescope, the GTC on the Canary Islands. Source: Wikipedia

Large Binocular Telescope; NASA

A Definition of Planets (2006) The discovery of more than 2,000 Kuiper-Belt-Objects made it clear than not everything out there (perhaps not even Pluto) was a planet. In August 2006, the International Astronomical Union voted on a definition of a planet. According to this definition, a body in the Solar System must meet three criteria to be classified as a planet: It has to be in orbit around the Sun. It must have sufficient mass to assume hydrostatic equilibrium (a nearly round shape). It must have cleared the neighborhood around its orbit.

Pluto; Wikipedia

Pluto only met two of the three criteria. For Pluto and other objects orbiting the Sun and large enough for hydrostatic equilibrium, a new category - Dwarf Planet was created. Currently, Ceres in the Asteroid Belt and Kuiper-Belt-Objects Pluto, Eris, Makemake and Haumea have been named Dwarf Planets. Source: Wikipedia

The World's Largest Single-Aperture Optical Telescope (2009) Keeping records of the world's largest telescopes became complicated since the Large Binocular Telescope in Arizona combined two mirrors to a world record image. But by any measure, the 10.4 meter (410 inches) mirror of the Gran Telescopio Canarias is the largest in the world. The observatory on the island of La Palma on the Canary Islands is largely financed by Spain with Mexico and the University of Florida each holding a five percent stake. The GTC began preliminary observations in 2007, but the official inauguration took place on July 24, 2009 Source: Wikipedia

Gran Telescopio Canarias; Wikipedia

Leaving Home (2012) On August 25, 2012, 18.2 billion kilometers (11.3 billion miles or 121.7 astronomical units) from the sun, the Voyager 1 space probe became the first human-built object to enter interstellar space. At this point the probe was no longer surrounded by solar particles but instead by a fog of galactic particles called the stellar wind. The probe registered a sharp drop in protons from the sun, from 25 particles per second in late August, to about 2 particles per second by early October, confirming the passage of the Heliopause, the last frontier of the Solar System.

Artist's concept of Voyager 1 passing the Heliopause Source: sciencenews.org

Voyager 1 and Voyager 2 were launched in 1977 to perform flybys of the outer planets. While Voyager 2 performed a so-called Grand Tour of passing Jupiter, Saturn, Uranus and Neptune, Voyager 1 was routes out of the plane of the planet's orbits after passing Saturn, to perform a close flyby of Saturn's moon Titan. Voyager 2 passed the Heliopause on November 5, 2018. To date, the two Voyager probes are the object furthest away from Earth and the oldest space probes that are still operational. Sources: Wikipedia, sciencenews.org

A Meteor Caught on Camera (2013) In the morning hours of February 15, 2013, a Superbolide entered the Earth's atmosphere and exploded at an altitude of 18.5 miles (29.7 km) over Chelyabinsk in Russia's Ural Mountains. It was estimated that the meteor had an initial mass of about 12,000 - 13,000 tons and a diameter of about 20 meters (66 ft). That made it not only the largest known natural object to have entered Earth's atmosphere since the 1908 Tunguska event, but also the largest meteor ever caught on camera. Click here for a short video of the event. Source: Wikipedia

Chelyabinsk Meteor Source: phys.org

A Billion Stars and counting (2013 - 2018) In times of refraction telescopes and pen and paper, the size of star catalogues was not only limited by the telescope's resolution but also - or even more so - by the limited time and the limited amount of numbers a human can scribble in any considerable amount of time. Modern computers have taken care of the problem. In 2013, the European Space Agency launched the Gaia space observatory, aiming to construct by far the largest and most precise 3D space catalog ever made. After two data releases in 2015 and 2018, the Gaia Star Catalogue currently contains no less than 1,692,919,135 objects, mainly stars, but also planets, comets, asteroids and quasars and others. Sources: Wikipedia, ESA, thewire.in

Artist's impression of the Gaia Telescope; ESA

Hubble Travels 13.4 billion Years Back in Time (2016) In March 2016, an international team of astronomers from Yale University, the Space Telescope Science Institute, and the University of California, using the Hubble Telescope observed an infant galaxy in the state it was in 13.4 billion years ago - just 400 million years after the Big Bang. From Earth, galaxy GN-z11 is seen in its infant stage. The fact that a galaxy so massive existed so soon after the first stars started to form challenged a number of theoretical models of the formation of galaxies. It took the light emitted by GN-z11 13.4 billion years to reach Earth, but - due to the Expansion of the universe it is currently about 32 billion light years away from us. Sources: Wikipedia, NASA

GN-z11; Source: Wikipedia

Icarus - A Star Across the Universe (2016) When traveling almost ten Billion years back in time, normally, the only objects the Hubble Telescope could detect are galaxies and occasional supernovae. But in April 2018, the magazine Nature Astronomy published an article written by Kelly, Patrick L.; et al., entitled Extreme magnification of an individual star at redshift 1.5 by a galaxy-cluster lens. It described the detection of an individual star in 2016 that would usually not be visible even with our best telescopes today. The light of blue supergiant MACS J1149 Lensed Star 1 traveled 9.34 billion years. At this distance, even a massive blue supergiant star would appear only at an apparent magnitude of about 30.

Icarus in a 2016 Hubble image Source: UC Berkeley

But for a short time in April and May 2016, the gravitational lens effects of a galaxy cluster and another object crossing the line of sight magnified the visible light of the star by a factor of about 600. The star, named Icarus became the most distant star ever observed directly in visible light. Due to the Expansion of the universe, there is a difference between the time the light traveled and the current distance between our Sun and Icarus, which is about 14.4 billion light years. Source: Wikipedia, University of California Berkeley

Our Closest Planetary Neighbor (2016) On July 20, 2016, the team of the European Southern Observatory announced the discovery of a planet in orbit of our closest neighbor, the star Proxima Centauri. Being "only" 4.244 light years away, in a few decades, planet Proxima Centauri B is likely to be the first expolanet to receive a visit from a space probe from Earth. Technically, the planet is within the habitable zone of its host star, but being subject to stellar wind pressures of more than 2,000 times those experienced by Earth, its habitability is questionable. Sources: Wikipedia, New York Times

Artist's conception of a sunrise on Proxima Centauri B Source: Wikipedia

A Super-Supernova (2016) On November 14, 2016, the Gaia space observatory observed the largest supernova in human records. SN 2016iet is about 900 million light-years away. Analysis of the event showed that SN2016iet began as an incredibly massive star about 200 times the mass of our Sun. The explosion may not have looked like much from almost a billion light-years away (see picture on top), but it was the most massive energy output ever observed (see artist's impression, picture below). Stars of 130-260 Sun-masses burn through its fuel quickly, living for only a few million years. There is a theory predicting that massive and low-metallicity stars (those with few elements other than hydrogen and helium) can begin making pairs of matter and antimatter in their last days. This causes a runaway effect where the pressure drops in the star’s core, causing a collapse, leading to an enormous explosion that completely destroys the star, leaving nothing behind, not even a black hole. Sources: Cornell University, sci-news.com, astronomy.com, Bob Moler

SN2016iet observed at Las Campanas Observatory Source: Harvard & Smithsonian Center for Astrophysics Artist's impression of SN2016iet © Gemini Observatory / NSF / AURA / Joy Pollard

FAST - The World's Largest Dish (2016) Completed in 2016, the Five-hundred-meter Aperture Spherical Telescope in southwest China is the world's largest filled-aperture radio telescope. Its 500 meter (1,600 ft) dish is built into a natural depression in the landscape. Its surface is made of metal panels that can be automatically tilted to help change the focus to different areas of the sky. Between August 1917 and September 2018, the telescope has discovered 44 new pulsars. Source: Wikipedia,

FAST; Source: china.org

A Picture of an Invisible Object (2019) In 2009, the Event Horizon Telescope (EHT), a large telescope array consisting of a global network of radio telescopes was formed. In April 2017, eight radio observatories on four continents started observing the center of Messier 87, a supergiant elliptical galaxy 54 million light-years away in the constellation Virgo. On April 10, 2019, after two years of data processing, EHT released the first direct image of a black hole, the one in the center of Messier 87. By nature, one cannot take a picture of a black hole, as it is not emitting any radiation. Instead the false color image shows a radio wave halo surrounding the event horizon. Source: Wikipedia

Black Hole at Messier 87 Source: Wikipedia

The Largest Map of the Universe (2020) On July 20, 2020, the team of the Sloan Digital Sky Survey (see above) released the largest-ever 3-D-map of the universe. In five years of data collection, over 100 astrophysicists contributed to the map. Most important part of the project was eBOSS, the Extended Baryon Oscillation Spectroscopic Survey, a survey of quasars and galaxies as part of the Sloan Survey. The map shows 11 billion years of the universe's history. Sources: scitechdaily.com, space.com

3-D-map of the Universe; Source: anews.com

This concludes our Journey through the history of astronomy. For condensed versions of astronomical history, check out our Time Line and our Constellations History site. Please also visit our Mythology section - the main part of this star lore project.

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