Astronomy, IS -LI
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
Is Earth Going to Change the Direction in Which It Rotates?
It’s not likely, but there are things that could stop Earth’s rotation and get it moving in the other direction.......
Ishtar Terra
Ishtar Terra, the smaller of two continent-sized highland areas (terrae) on the planet Venus. Ishtar lies in Venus’s......
It’s Winter! It’s Summer!
Are you getting out your snow boots or your swimsuits? Those of us in the Northern Hemisphere think of December......
Ivanov, Georgi
Georgi Ivanov is a Bulgarian cosmonaut who became the first Bulgarian in space. Ivanov graduated from the Bulgarian......
Ixchel
Ixchel, Mayan moon goddess. Ixchel was the patroness of womanly crafts but was often depicted as an evil old woman......
James Webb Space Telescope
James Webb Space Telescope (JWST), U.S.–European Space Agency–Canadian satellite observatory designed as the successor......
Janssen, Pierre
Pierre Janssen was a French astronomer who in 1868 discovered the chemical element helium and how to observe solar......
Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency (JAXA), Japanese government agency in charge of research in both aviation and......
Jeans, Sir James
Sir James Jeans was an English physicist and mathematician who was the first to propose that matter is continuously......
Jeffreys, Sir Harold
Sir Harold Jeffreys was a British astronomer and geophysicist noted for his wide variety of scientific contributions.......
Jemison, Mae
Mae Jemison is an American physician and the first African American woman to become an astronaut. In 1992, she......
Jia Xian
Jia Xian was a mathematician and astronomer active at the beginning of the greatest period of traditional Chinese......
Jodrell Bank Observatory
Jodrell Bank Observatory, location of one of the world’s largest fully steerable radio telescopes, which has a......
Jones, Sir Harold Spencer
Sir Harold Spencer Jones was the 10th astronomer royal of England (1933–55), who organized a program that led to......
Jordan, Pascual
Pascual Jordan was a German theoretical physicist who was one of the founders of quantum mechanics and quantum......
Juno
Juno, U.S. space probe designed to orbit the planet Jupiter. The probe is named for a Roman goddess, the female......
Jupiter
Jupiter, the most massive planet of the solar system and the fifth in distance from the Sun. It is one of the brightest......
Jähn, Sigmund
Sigmund Jähn was an East German cosmonaut who became the first German in space. As a young man Jähn trained to......
K2-18b
K2-18b, extrasolar planet for which, on the basis of a possible detection of dimethyl sulfide (DMS) and dimethyl......
Kadenyuk, Leonid
Leonid Kadenyuk was a Ukrainian cosmonaut who flew on the U.S. space shuttle Columbia and was the first Ukrainian......
Kaguya
Kaguya, Japan’s second unmanned mission to the Moon, launched by the Japan Aerospace Exploration Agency in September......
Kamacite
Kamacite, mineral consisting of iron alloyed with 5–7 percent nickel by weight and found in almost all meteorites......
Kanai, Norishige
Norishige Kanai is a Japanese medical doctor and astronaut who began a stay of about six months at the International......
Kapteyn, Jacobus Cornelius
Jacobus Cornelius Kapteyn was a Dutch astronomer who used photography and statistical methods in determining the......
Kardashev scale
Kardashev scale, hypothetical measure of an alien civilization’s level of technological advancement, proposed by......
Keck Observatory
Keck Observatory, astronomical observatory located near the 4,200-metre (13,800-foot) summit of Mauna Kea, a dormant......
Keeler, James
James Keeler was an American astronomer who confirmed that Saturn’s ring system is not a solid unit but is composed......
Kelly, Mark
Mark Kelly’s life story could be told as a fairy tale, as science fiction, as a romance novel, or as a tale of......
Kelly, Scott
Scott Kelly is an American astronaut who made four spaceflights, the longest of which lasted 340 days. He is the......
Kennedy Space Center
Kennedy Space Center, one of NASA’s 10 field centers and its primary launch center for human spaceflight, located......
Kepler
Kepler, U.S. satellite that detected extrasolar planets by watching—from orbit around the Sun—for a slight dimming......
Kepler, Johannes
Johannes Kepler German astronomer who discovered three major laws of planetary motion, conventionally designated......
Kepler-186f
Kepler-186f, the first Earth-sized extrasolar planet to be found within its star’s habitable zone—the orbital region......
Kepler-452b
Kepler-452b, the first approximately Earth-sized planet to be found in a Sun-like star’s habitable zone—the orbital......
Keplerian telescope
Keplerian telescope, instrument for viewing distant objects, the basis for the modern refractive telescope, named......
Kepler’s laws of planetary motion
Kepler’s laws of planetary motion, in astronomy and classical physics, laws describing the motions of the planets......
Kepler’s Nova
Kepler’s Nova, one of the few supernovae (violent stellar explosions) known to have occurred in the Milky Way Galaxy.......
Kepler’s second law of planetary motion
Kepler’s second law of planetary motion, in astronomy and classical physics, one of three laws describing the motions......
Kerr, Roy
Roy Kerr is a New Zealand mathematician who solved (1963) Einstein’s field equations of general relativity to describe......
Kerwin, Joseph
Joseph Kerwin is a U.S. astronaut and physician who served as science pilot on Skylab 2, the first crewed mission......
Khonsu
Khonsu, in ancient Egyptian religion, moon god who was generally depicted as a youth. A deity with astronomical......
Kidinnu
Kidinnu was a Babylonian astronomer who may have been responsible for what modern scholars call System B, a Babylonian......
Kim, Jonny
Jonny Kim is a Korean American Navy SEAL, doctor, aviator, and astronaut who is a member of NASA’s Artemis team,......
Kirch, Maria
Maria Kirch was a German astronomer who was the first woman to discover a comet. Winckelmann was educated by her......
Kircher, Athanasius
Athanasius Kircher was a Jesuit priest and scholar, sometimes called the last Renaissance man, important for his......
Kirchhoff, Gustav
Gustav Kirchhoff was a German physicist who, with the chemist Robert Bunsen, firmly established the theory of spectrum......
Kirkwood gaps
Kirkwood gaps, interruptions that appear in the distribution of asteroid semimajor axes where the orbital period......
Kitt Peak National Observatory
Kitt Peak National Observatory (KPNO), astronomical observatory located on the Papago Indian Reservation 50 miles......
Klimuk, Pyotr
Pyotr Klimuk is a Soviet cosmonaut who flew three times in space and was head of the Yury Gagarin Cosmonaut Training......
Koch, Christina
Christina Koch is an American astronaut who became the first woman to travel around the Moon when she flew as a......
Komarov, Vladimir Mikhaylovich
Vladimir Mikhaylovich Komarov was a Soviet cosmonaut, the first man known to have died during a space mission.......
Kondakova, Yelena
Yelena Kondakova is a Russian cosmonaut who was the first woman to make a long-duration spaceflight. Kondakova......
Korea Space Launch Vehicle-1
Korea Space Launch Vehicle-1 (KSLV-1), series of South Korean launch vehicles that were designed to launch Earth-orbiting......
Korolev, Sergei
Sergei Korolev was a Soviet designer of guided missiles, rockets, and spacecraft. Korolev was educated at the Odessa......
Kosmos
Kosmos, any of a series of uncrewed Soviet and then Russian satellites launched from the early 1960s to the present......
Kozyrev, Nikolay Aleksandrovich
Nikolay Aleksandrovich Kozyrev was a Russian astronomer, who claimed to have discovered volcano-like activity on......
Krikalyov, Sergey Konstantinovich
Sergey Konstantinovich Krikalyov is a Russian cosmonaut whose six spaceflights from 1988 to 2005 earned him the......
Krishnan, Ajit
Ajit Krishnan is one of the four astronauts selected for India’s first crewed spaceflight program, Gaganyaan, scheduled......
Kubasov, Valery
Valery Kubasov was a Russian cosmonaut who performed the first welding experiments in space. Upon graduating from......
Kuiper Airborne Observatory
Kuiper Airborne Observatory (KAO), a Lockheed C-141 jet transport aircraft specially instrumented for astronomical......
Kuiper belt
Kuiper belt, flat ring of icy small bodies that revolve around the Sun beyond the orbit of the planet Neptune.......
Kuiper, Gerard Peter
Gerard Peter Kuiper was a Dutch-American astronomer known especially for his discoveries and theories concerning......
Kushukh
Kushukh, the Hurrian moon god. In the Hurrian pantheon, Kushukh was regularly placed above the sun god, Shimegi;......
Kwangmyŏngsŏng
Kwangmyŏngsŏng, any of a North Korean series of satellites. The first successful satellite, Kwangmyŏngsŏng 3, entered......
Kármán line
Kármán line, boundary separating Earth’s atmosphere and outer space. The line is neither sharp nor well defined......
Kármán, Theodore von
Theodore von Kármán was a Hungarian-born American research engineer best known for his pioneering work in the use......
Kāshī, al-
al-Kāshī was among the greatest mathematicians and astronomers in the Islamic world. The first event known with......
Lacaille, Nicolas Louis de
Nicolas Louis de Lacaille was a French astronomer who mapped the constellations visible from the Southern Hemisphere......
Lacerta
Lacerta, constellation in the northern sky at about 22.5 hours right ascension and 45° north in declination. Its......
Lagoon Nebula
Lagoon Nebula, (catalog numbers NGC 6523 and M8), ionized-hydrogen region located in the constellation Sagittarius......
Lagrange point
Lagrange point, in astronomy, a point in space at which a small body, under the gravitational influence of two......
Lagrange, Joseph-Louis, comte de l’Empire
Joseph-Louis Lagrange, comte de l’Empire was an Italian French mathematician who made great contributions to number......
Laika
Laika, a dog that was the first living creature to be launched into Earth orbit, on board the Soviet artificial......
Lalande, Jérôme
Jérôme Lalande was a French astronomer whose tables of planetary positions were considered the best available until......
Lambert, Johann Heinrich
Johann Heinrich Lambert was a Swiss German mathematician, astronomer, physicist, and philosopher who provided the......
Lamont, Johann von
Johann von Lamont was a Scottish-born German astronomer noted for discovering that the magnetic field of the Earth......
Landau, Lev Davidovich
Lev Davidovich Landau was a Soviet theoretical physicist, one of the founders of the quantum theory of condensed......
Landsat
Landsat, any of a series of unmanned U.S. scientific satellites. The first three Landsat satellites were launched......
Lane, Jonathan Homer
Jonathan Homer Lane was a U.S. astrophysicist who was the first to investigate mathematically the Sun as a gaseous......
Langley, Samuel Pierpont
Samuel Pierpont Langley was an American astrophysicist and aeronautical pioneer who developed new instruments with......
Laplace, Pierre-Simon, marquis de
Pierre-Simon, marquis de Laplace was a French mathematician, astronomer, and physicist who was best known for his......
Large Binocular Telescope Observatory
Large Binocular Telescope Observatory (LBTO), observatory consisting of two 8.4-metre (28-foot) telescopes located......
Las Campanas Observatory
Las Campanas Observatory (LCO), astronomical observatory established in 1969 in the Atacama desert of Chile at......
Laser Interferometer Gravitational-Wave Observatory
Laser Interferometer Gravitational-Wave Observatory (LIGO), astronomical observatory located in Hanford, Washington,......
Laser Interferometer Space Antenna
Laser Interferometer Space Antenna (LISA), European group of three spacecraft that are designed to search for gravitational......
Lassell, William
William Lassell was an amateur English astronomer who discovered Ariel and Umbriel, satellites of Uranus; and Triton,......
launch vehicle
launch vehicle, in spaceflight, a rocket-powered vehicle used to transport a spacecraft beyond Earth’s atmosphere,......
Lawrence, Robert Henry, Jr.
Robert Henry Lawrence, Jr. was a U.S. Air Force major who was the first African American astronaut in the U.S.......
LCROSS
LCROSS, U.S. spacecraft that was deliberately crashed into the Moon on October 9, 2009, resulting in the discovery......
Le Verrier, Urbain-Jean-Joseph
Urbain-Jean-Joseph Le Verrier was a French astronomer who predicted by mathematical means the existence of the......
Leavitt, Henrietta Swan
Henrietta Swan Leavitt was an American astronomer known for her discovery of the relationship between period and......
Lemaître, Georges
Georges Lemaître was a Belgian astronomer and cosmologist who formulated the modern big-bang theory, which holds......
Leo
Leo, in astronomy, zodiacal constellation lying in the northern sky between Cancer and Virgo, between about 9 hours......
Leo Minor
Leo Minor, constellation in the northern sky at about 10 hours right ascension and 35° north in declination. Its......
Leonardo da Vinci
Leonardo da Vinci was an Italian painter, draftsman, sculptor, architect, and engineer whose skill and intelligence,......
Leonardo da Vinci’s parachute
Leonardo da Vinci discussed the parachute in a notebook entry now contained in the Codex Atlanticus. Although it......
Leonov, Aleksei
Aleksei Leonov was a Soviet cosmonaut who performed the first space walk. After early schooling in Kaliningrad,......
Lepus
Lepus, constellation in the southern sky at about 6 hours right ascension and 20° south in declination. Its brightest......
Levy, David H.
David H. Levy is a Canadian astronomer and science writer who discovered—along with Carolyn Shoemaker and Eugene......
Li Chunfeng
Li Chunfeng was a Chinese mathematician and astronomer. Li was the son of a widely educated state official. He......