Astronomy, STR-UNI
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.
Astronomy Encyclopedia Articles By Title
Otto Struve was a Russian-American astronomer known for his contributions to stellar spectroscopy, notably the......
Bengt Strömgren was a Danish astrophysicist who pioneered the present-day knowledge of the gas clouds in space.......
Subaru Telescope, a Japanese 8.2-metre (27-foot) optical-infrared telescope located on the dormant volcano Mauna......
Kathryn Sullivan is an American oceanographer and astronaut who in 1984 became the first American woman to walk......
summer solstice, the two moments during the year when the path of the Sun in the sky is farthest north in the Northern......
Sun, star around which Earth and the other components of the solar system revolve. It is the dominant body of the......
- Introduction
- Core, Radiation, Layers
- Evolution, Structure, Radiation
- Solar Atmosphere, Radiation, Core
- Chromosphere, Corona, Solar Flares
- Corona, Solar Wind, Radiation
- Solar Activity, Radiation, Coronal Mass Ejections
- Prominences, Solar Flares, Coronal Mass Ejections
- Flares, Solar Activity, Coronal Mass Ejections
- Solar Activity, Radiation, Atmosphere
- Astronomy, Heliophysics, Observations
sunlight, solar radiation that is visible at Earth’s surface. The amount of sunlight is dependent on the extent......
sunspot, vortex of gas on the surface of the Sun associated with strong local magnetic activity. Spots look dark......
Rashid Sunyaev is a Russian-German astrophysicist who, with Soviet physicist Yakov Zeldovich, first proposed the......
super-Earth, type of planet that is between about 2 to 10 times the mass of Earth. Some astronomers use a size......
supercluster, a group of galaxy clusters typically consisting of 3 to 10 clusters and spanning as many as 200,000,000......
supergiant star, any star of very great intrinsic luminosity and relatively enormous size, typically several magnitudes......
supergravity, a type of quantum field theory of elementary subatomic particles and their interactions that is based......
supermassive black hole (SMBH), a black hole more than one hundred thousand times the mass of the Sun. Nearly every......
supermoon, a full moon that occurs when the Moon is at perigee (the closest point to Earth in its orbit). The Moon......
supernova, any of a class of violently exploding stars whose luminosity after eruption suddenly increases many......
Supernova 1987A, first supernova observed in 1987 (hence its designation) and the nearest to Earth in more than......
supernova remnant, nebula left behind after a supernova, a spectacular explosion in which a star ejects most of......
Surveyor, any of a series of seven unmanned U.S. space probes sent to the Moon between 1966 and 1968 to photograph......
Surya, in Hinduism, both the Sun and the Sun god. Although in the Vedic period (1500–5th century bce) several other......
Suzaku, is a Japanese-U.S. satellite observatory designed to observe celestial X-ray sources. Suzaku was launched......
Svarozhich, in Slavic religion, god of the sun, of fire, and of the hearth. He was worshiped in a temple at Radegast......
Emanuel Swedenborg was a Swedish scientist, Christian mystic, philosopher, and theologian who wrote voluminously......
Swift, U.S. satellite observatory designed to swing into the proper orientation to catch the first few seconds......
Jack Swigert was a U.S. astronaut and command module pilot on the Apollo 13 mission (April 11–17, 1970), in which......
Pol Swings was a Belgian astrophysicist noted for his spectroscopic studies of the composition and structure of......
synchrotron radiation, electromagnetic energy emitted by charged particles (e.g., electrons and ions) that are......
synodic period, the time required for a body within the solar system, such as a planet, the Moon, or an artificial......
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, nickel-iron mineral having a face-centred cubic structure and playing a major role in the crystallization......
Arnaldo Tamayo Méndez is a Cuban pilot and cosmonaut. He was the first Latin American, the first person of African......
Tarantula Nebula, (catalog number NGC 2070) immense ionized-hydrogen region in the Large Magellanic Cloud, a satellite......
Jill Tarter is an American astronomer known for her work in the search for extraterrestrial intelligence (SETI).......
Taurus, in astronomy, zodiacal constellation lying in the northern sky between Aries and Gemini, at about 4 hours......
Taurus-Littrow Valley, region on the Moon where the Apollo 17 lunar mission landed. Located at 22° N 31° E, it......
telescope, device used to form magnified images of distant objects. The telescope is undoubtedly the most important......
Recently the world’s largest single-dish radio telescope was completed in China. The Five-hundred-metre Aperture......
Telescopium, constellation in the southern sky at about 19 hours right ascension and 50° south in declination.......
Telstar, series of communications satellites whose successful launching, beginning in 1962, inaugurated a new age......
Valentina Tereshkova is a Soviet cosmonaut and the first woman to travel into space. On June 16, 1963, she was......
Tethys, major regular moon of Saturn, remarkable for a fissure that wraps around the greater part of its circumference.......
Thales of Miletus was a philosopher renowned as one of the legendary Seven Wise Men, or Sophoi, of antiquity. He......
On a clear night, staring up at the stars induces a sense of simultaneous wonder and insignificance. Humanity time......
On March 18, 1965, cosmonaut Aleksey Leonov rocketed into Earth orbit and exited his spacecraft, becoming the first......
Stars begin their life cycle in molecular clouds. These clouds contain dense clumps of gas and dust, which can......
In the first decades of the 21st century, a new space race emerged between India, China, and Japan. This infographic......
In February 1919 two teams of astronomers from the Greenwich and Cambridge observatories set out for Sobral, Brazil,......
Without a scientific explanation, the darkening of the Sun (or Moon) during an eclipse would be a startling event,......
THEMIS, five U.S. satellites that studied variations in the aurora. The spacecraft were launched by the National......
Robert Thirsk is the first Canadian astronaut to make a long-duration spaceflight. Thirsk received bachelor’s and......
Thor rocket, missile initially developed by the U.S. Air Force as an intermediate-range ballistic missile. It was......
Kip Thorne is an American physicist who was awarded the 2017 Nobel Prize for Physics for his work on the Laser......
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, 14th-century cosmology that is the oldest known full-length text written......
three-body problem, in astronomy, the problem of determining the motion of three celestial bodies moving under......
Tiangong, any of a series of three Chinese space stations, the first of which was launched on September 29, 2011.......
tidal friction, in astronomy, strain produced in a celestial body (such as the Earth or Moon) that undergoes cyclic......
tide, any of the cyclic deformations of one astronomical body caused by the gravitational forces exerted by others.......
Apollo was a project conducted by the U.S. National Aeronautics and Space Administration (NASA) in the 1960s and......
This infographic presents a timeline of space-related achievements by the U.S.S.R. and the U.S. between 1957 and......
TIROS, any of a series of U.S. meteorological satellites, the first of which was launched on April 1, 1960. The......
Félix Tisserand was a French astronomer noted for his textbook Traité de mécanique céleste, 4 vol. (1889–96; “Treatise......
Titan, the largest moon of Saturn and the only moon in the solar system known to have clouds and a dense atmosphere.......
Titan rocket, any of a series of U.S. rockets that were originally developed as intercontinental ballistic missiles......
Titania, largest of the moons of Uranus. It was first detected telescopically in 1787 by the English astronomer......
Johann Daniel Titius was a Prussian astronomer, physicist, and biologist whose law (1766) expressing the distances......
Dennis Tito is an American businessman who became the first private individual to pay for his own trip into space.......
Gherman Stepanovich Titov was a Soviet cosmonaut who piloted the Vostok 2 spacecraft, launched on August 6, 1961,......
On this day in 1978 NASA made an announcement: It had recruited the first new class of astronauts in almost a decade.......
Black holes sound like science fiction: collapsed stars whose incomprehensibly powerful gravitational pull absorbs......
In the long span of UFO sightings, which range from obvious hoaxes to truly unexplained phenomena, the Trans-en-Provence......
Clyde Tombaugh was an American astronomer who discovered Pluto in 1930 after a systematic search for a ninth planet......
Transit, any of the first series of U.S. navigation satellites. Launched by the U.S. Navy from 1960 to 1988, the......
transit, in astronomy, the passage of a relatively small body across the disk of a larger body, usually a star......
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 (TRACE), U.S. satellite designed to study the solar corona. It was launched......
Triangulum, constellation in the northern sky at about 2 hours right ascension and 30° north in declination. Its......
Triangulum Australe, constellation in the southern sky at about 16 hours right ascension and 65° south in declination.......
Trifid Nebula, (catalog numbers NGC 6514 and M 20), bright, diffuse nebula in the constellation Sagittarius, lying......
Triton, largest of Neptune’s moons, whose unusual orbital characteristics suggest that it formed elsewhere in the......
Trojan asteroid, any one of a number of asteroids that occupy a stable Lagrangian point in a planet’s orbit around......
Robert Julius Trumpler was a Swiss-born U.S. astronomer who, in his extensive studies of galactic star clusters,......
TRW Inc., major American industrial corporation providing advanced-technology products and services primarily in......
Konstantin Tsiolkovsky was a Russian research scientist in aeronautics and astronautics who pioneered rocket and......
Tucana, constellation in the southern sky at about 0 hour right ascension and 60° south in declination. Its brightest......
Herbert Hall Turner was an English astronomer who pioneered many of the procedures now universally employed in......
Phạm Tuân is a Vietnamese pilot and cosmonaut, the first Vietnamese citizen in space. Tuân joined the Vietnam People’s......
Tycho, conspicuous impact crater resulting from an impact event and lying at the centre of the most extensive system......
Tychonic system, scheme for the structure of the solar system put forward in 1583 by the Danish astronomer Tycho......
Tycho’s Nova, one of the few recorded supernovas in the Milky Way Galaxy. The Danish astronomer Tycho Brahe first......
Neil deGrasse Tyson is an American astronomer who popularized science with his books and frequent appearances on......
U Geminorum star, any of a class of irregular variable stars that display sudden increases in brightness so great......
UBV system, system of classifying stars by spectral type, based on photometric measurements of the ultraviolet......
ultraviolet astronomy, study of the ultraviolet spectra of astronomical objects. Ultraviolet radiation comes from......
ultraviolet telescope, telescope used to examine the ultraviolet portion of the electromagnetic spectrum, between......
Ulysses, joint European-U.S. space probe launched in 1990 that was the first spacecraft to fly over the poles of......
umbra, that part of a shadow in which all light from a given source is excluded. The shadow from a point source......
Umbriel, third nearest of the five major moons of Uranus and the one having the darkest and oldest surface of the......
In the early 17th century, German astronomer Johannes Kepler postulated three laws of planetary motion. His laws......
unidentified flying object (UFO), any aerial object or optical phenomenon not readily identifiable to the observer.......