Astronomy, SUR-VER

Human beings have long been fascinated by the celestial sphere above, whose twinkling lights have inspired not only scientific theories but also many artistic endeavors. Humankind's fascination with the world beyond Earth has led to many landmark moments in history, as when space exploration took a giant step forward with the advent of technology that allowed humans to successfully travel to the Moon and to build spacecraft capable of exploring the rest of the solar system and beyond.
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Astronomy Encyclopedia Articles By Title

Surveyor
Surveyor, any of a series of seven unmanned U.S. space probes sent to the Moon between 1966 and 1968 to photograph......
Surya
Surya, in Hinduism, both the Sun and the Sun god. Although in the Vedic period (1500–5th century bce) several other......
Suzaku
Suzaku, is a Japanese-U.S. satellite observatory designed to observe celestial X-ray sources. Suzaku was launched......
Svarozhich
Svarozhich, in Slavic religion, god of the sun, of fire, and of the hearth. He was worshiped in a temple at Radegast......
Swedenborg, Emanuel
Emanuel Swedenborg was a Swedish scientist, Christian mystic, philosopher, and theologian who wrote voluminously......
Swift
Swift, U.S. satellite observatory designed to swing into the proper orientation to catch the first few seconds......
Swigert, Jack
Jack Swigert was a U.S. astronaut and command module pilot on the Apollo 13 mission (April 11–17, 1970), in which......
Swings, Pol
Pol Swings was a Belgian astrophysicist noted for his spectroscopic studies of the composition and structure of......
synchrotron radiation
synchrotron radiation, electromagnetic energy emitted by charged particles (e.g., electrons and ions) that are......
synodic period
synodic period, the time required for a body within the solar system, such as a planet, the Moon, or an artificial......
T Tauri star
T Tauri star, any of a class of very young stars having a mass of the same order as that of the Sun. So called......
taenite
taenite, nickel-iron mineral having a face-centred cubic structure and playing a major role in the crystallization......
Tamayo Méndez, Arnaldo
Arnaldo Tamayo Méndez is a Cuban pilot and cosmonaut. He was the first Latin American, the first person of African......
Tarantula Nebula
Tarantula Nebula, (catalog number NGC 2070) immense ionized-hydrogen region in the Large Magellanic Cloud, a satellite......
Tarter, Jill
Jill Tarter is an American astronomer known for her work in the search for extraterrestrial intelligence (SETI).......
Taurus
Taurus, in astronomy, zodiacal constellation lying in the northern sky between Aries and Gemini, at about 4 hours......
Taurus-Littrow Valley
Taurus-Littrow Valley, region on the Moon where the Apollo 17 lunar mission landed. Located at 22° N 31° E, it......
Telescopes: Seeing Stars
Recently the world’s largest single-dish radio telescope was completed in China. The Five-hundred-metre Aperture......
Telescopium
Telescopium, constellation in the southern sky at about 19 hours right ascension and 50° south in declination.......
Telstar
Telstar, series of communications satellites whose successful launching, beginning in 1962, inaugurated a new age......
Tereshkova, Valentina
Valentina Tereshkova is a Soviet cosmonaut and the first woman to travel into space. On June 16, 1963, she was......
Tethys
Tethys, major regular moon of Saturn, remarkable for a fissure that wraps around the greater part of its circumference.......
Thales of Miletus
Thales of Miletus was a philosopher renowned as one of the legendary Seven Wise Men, or Sophoi, of antiquity. He......
The Fermi Paradox: Where Are All the Aliens?
On a clear night, staring up at the stars induces a sense of simultaneous wonder and insignificance. Humanity time......
The First Space Walk
On March 18, 1965, cosmonaut Aleksey Leonov rocketed into Earth orbit and exited his spacecraft, becoming the first......
The Great Moon Hoax of 1835 Was Sci-Fi Passed Off as News
So reads part of the first installment of what would later be called the Great Moon Hoax. The series of six articles,......
The Life Cycle of a Star
Stars begin their life cycle in molecular clouds, which are dense regions of gas and dust in space. These clouds......
The Solar Eclipse That Made Albert Einstein a Science Celebrity
In February 1919 two teams of astronomers from the Greenwich and Cambridge observatories set out for Sobral, Brazil,......
The Sun Was Eaten: 6 Ways Cultures Have Explained Eclipses
Without a scientific explanation, the darkening of the Sun (or Moon) during an eclipse would be a startling event,......
THEMIS
THEMIS, five U.S. satellites that studied variations in the aurora. The spacecraft were launched by the National......
Thirsk, Robert
Robert Thirsk is the first Canadian astronaut to make a long-duration spaceflight. Thirsk received bachelor’s and......
Thor rocket
Thor rocket, missile initially developed by the U.S. Air Force as an intermediate-range ballistic missile. It was......
Thorne, Kip
Kip Thorne is an American physicist who was awarded the 2017 Nobel Prize for Physics for his work on the Laser......
Thoth
Thoth, in Egyptian religion, a god of the moon, of reckoning, of learning, and of writing. He was held to be the......
Three Worlds According to King Ruang
Three Worlds According to King Ruang, 14th-century cosmology that is the oldest known full-length text written......
three-body problem
three-body problem, in astronomy, the problem of determining the motion of three celestial bodies moving under......
Tiangong
Tiangong, any of a series of three Chinese space stations, the first of which was launched on September 29, 2011.......
tidal friction
tidal friction, in astronomy, strain produced in a celestial body (such as the Earth or Moon) that undergoes cyclic......
tide
tide, any of the cyclic deformations of one astronomical body caused by the gravitational forces exerted by others.......
Timeline of the Apollo Space Missions
Apollo was a project conducted by the U.S. National Aeronautics and Space Administration (NASA) in the 1960s and......
Timeline of the Space Race, 1957–69
This infographic presents a timeline of space-related achievements by the U.S.S.R. and the U.S. between 1957 and......
TIROS
TIROS, any of a series of U.S. meteorological satellites, the first of which was launched on April 1, 1960. The......
Tisserand, Félix
Félix Tisserand was a French astronomer noted for his textbook Traité de mécanique céleste, 4 vol. (1889–96; “Treatise......
Titan
Titan, the largest moon of Saturn and the only moon in the solar system known to have clouds and a dense atmosphere.......
Titan rocket
Titan rocket, any of a series of U.S. rockets that were originally developed as intercontinental ballistic missiles......
Titania
Titania, largest of the moons of Uranus. It was first detected telescopically in 1787 by the English astronomer......
Titius, Johann Daniel
Johann Daniel Titius was a Prussian astronomer, physicist, and biologist whose law (1766) expressing the distances......
Tito, Dennis
Dennis Tito is an American businessman who became the first private individual to pay for his own trip into space.......
Titov, Gherman Stepanovich
Gherman Stepanovich Titov was a Soviet cosmonaut who piloted the Vostok 2 spacecraft, launched on August 6, 1961,......
Tombaugh, Clyde
Clyde Tombaugh was an American astronomer who discovered Pluto in 1930 after a systematic search for a ninth planet......
Transit
Transit, any of the first series of U.S. navigation satellites. Launched by the U.S. Navy from 1960 to 1988, the......
transit
transit, in astronomy, the passage of a relatively small body across the disk of a larger body, usually a star......
Transit of Mercury
On Monday, May 9, 2016, viewers on Earth can see a transit of Mercury, in which that planet crosses in front of......
Transition Region and Coronal Explorer
Transition Region and Coronal Explorer (TRACE), U.S. satellite designed to study the solar corona. It was launched......
Triangulum
Triangulum, constellation in the northern sky at about 2 hours right ascension and 30° north in declination. Its......
Triangulum Australe
Triangulum Australe, constellation in the southern sky at about 16 hours right ascension and 65° south in declination.......
Trifid Nebula
Trifid Nebula, (catalog numbers NGC 6514 and M 20), bright, diffuse nebula in the constellation Sagittarius, lying......
Triton
Triton, largest of Neptune’s moons, whose unusual orbital characteristics suggest that it formed elsewhere in the......
Trojan asteroid
Trojan asteroid, any one of a number of asteroids that occupy a stable Lagrangian point in a planet’s orbit around......
Trumpler, Robert Julius
Robert Julius Trumpler was a Swiss-born U.S. astronomer who, in his extensive studies of galactic star clusters,......
TRW Inc.
TRW Inc., major American industrial corporation providing advanced-technology products and services primarily in......
Tsiolkovsky, Konstantin
Konstantin Tsiolkovsky was a Russian research scientist in aeronautics and astronautics who pioneered rocket and......
Tucana
Tucana, constellation in the southern sky at about 0 hour right ascension and 60° south in declination. Its brightest......
Turner, Herbert Hall
Herbert Hall Turner was an English astronomer who pioneered many of the procedures now universally employed in......
Tuân, Phạm
Phạm Tuân is a Vietnamese pilot and cosmonaut, the first Vietnamese citizen in space. Tuân joined the Vietnam People’s......
Tycho
Tycho, conspicuous impact crater resulting from an impact event and lying at the centre of the most extensive system......
Tychonic system
Tychonic system, scheme for the structure of the solar system put forward in 1583 by the Danish astronomer Tycho......
Tycho’s Nova
Tycho’s Nova, one of the few recorded supernovas in the Milky Way Galaxy. The Danish astronomer Tycho Brahe first......
Tyson, Neil deGrasse
Neil deGrasse Tyson is an American astronomer who popularized science with his books and frequent appearances on......
U Geminorum star
U Geminorum star, any of a class of irregular variable stars that display sudden increases in brightness so great......
UBV system
UBV system, system of classifying stars by spectral type, based on photometric measurements of the ultraviolet......
ultraviolet astronomy
ultraviolet astronomy, study of the ultraviolet spectra of astronomical objects. Ultraviolet radiation comes from......
ultraviolet telescope
ultraviolet telescope, telescope used to examine the ultraviolet portion of the electromagnetic spectrum, between......
Ulysses
Ulysses, joint European-U.S. space probe launched in 1990 that was the first spacecraft to fly over the poles of......
umbra
umbra, that part of a shadow in which all light from a given source is excluded. The shadow from a point source......
Umbriel
Umbriel, third nearest of the five major moons of Uranus and the one having the darkest and oldest surface of the......
Understanding Kepler’s Laws of Planetary Motion
In the early 17th century, German astronomer Johannes Kepler postulated three laws of planetary motion. His laws......
unidentified flying object
unidentified flying object (UFO), any aerial object or optical phenomenon not readily identifiable to the observer.......
Unidentified Flying Objects: What We Know
Everything we know (and only what we know) about the phenomenon of UFOs. Companion, UFO, UFOs, flying saucers,......
United States Naval Observatory
United States Naval Observatory (USNO), in Washington, D.C., an official source, with the U.S. National Institute......
universe
universe, the whole cosmic system of matter and energy of which Earth, and therefore the human race, is a part.......
Urania
Urania, in Greek religion, one of the nine Muses, patron of astronomy. In some accounts she was the mother of Linus......
Uraniborg
Uraniborg, observatory established in 1576 by the Danish astronomer Tycho Brahe. It was the last of the primitive......
Uranus
Uranus, seventh planet in distance from the Sun and the least massive of the solar system’s four giant, or Jovian,......
Urey, Harold C.
Harold C. Urey was an American scientist awarded the Nobel Prize for Chemistry in 1934 for his discovery of the......
Ursa Major
Ursa Major, in astronomy, a constellation of the northern sky, at about 10 hours 40 minutes right ascension and......
Ursa Minor
Ursa Minor, in astronomy, a constellation of the northern sky, at about 15 hours right ascension and 80° north......
Vanguard
Vanguard, any of a series of three uncrewed U.S. experimental test satellites. Vanguard 1, launched March 17, 1958,......
Varahamihira
Varahamihira was an Indian philosopher, astronomer, and mathematician, author of the Pancha-siddhantika (“Five......
variable star
variable star, any star whose observed light varies notably in intensity. The changes in brightness may be periodic,......
Vega
Vega, brightest star in the northern constellation Lyra and fifth brightest in the night sky, with a visual magnitude......
Vela
Vela, any of a series of 12 unmanned U.S. reconnaissance satellites developed to detect radiation from nuclear......
Vela
Vela, constellation in the southern sky at about 10 hours right ascension and 50° south in declination. Its brightest......
Velikovsky, Immanuel
Immanuel Velikovsky was an American writer, proponent of controversial theories of cosmogony and history. Educated......
Venera
Venera, any of a series of unmanned Soviet planetary probes that were sent to Venus. Radio contact was lost with......
Venus Express
Venus Express, European Space Agency spacecraft that orbited the planet Venus. The design of Venus Express was......
vernal equinox
vernal equinox, two moments in the year when the Sun is exactly above the Equator and day and night are of equal......
Very Large Array
Very Large Array (VLA), radio telescope system situated on the plains of San Agustin near Socorro, New Mexico,......

Astronomy Encyclopedia Articles By Title