• 0-9
  • a
  • b
  • c
  • d
  • e
  • f
  • g
  • h
  • i
  • j
  • k
  • l
  • m
  • n
  • o
  • p
  • q
  • r
  • s
  • t
  • u
  • v
  • w
  • x
  • y
  • z
  • Lumbwa (people)

    Kipsikis, largest ethnic group of the Southern Nilotic (Kalenjin) language group. They occupy the highlands around the town of Kericho in southwestern Kenya. Like other Nandi speakers, they originated in the highlands north of Lake Rudolf (Lake Turkana) and moved southward at least 1,000 years ago.

  • Lumbye, H. C. (Danish composer)

    Tivoli: The composer H.C. Lumbye (1810–74) conducted the orchestra at Tivoli for its first 30 years, playing popular Viennese dance music as well as his own compositions. Bombing in 1944 destroyed many park buildings, including the old concert hall; a new concert hall, seating 2,000, was opened in…

  • lumen (unit of energy measurement)

    Lumen, unit of luminous flux, or amount of light, defined as the amount streaming outward through one steradian (a unit of solid angle, part of the volume of space illuminated by a light source) from a uniform point source having an intensity of one candela. The lumen is used in calculations

  • lumen (anatomy)

    human respiratory system: The larynx: …vocal cords span the laryngeal lumen. They correspond to elastic ligaments attached anteriorly in the angle of the thyroid shield and posteriorly to a pair of small pyramidal pieces of cartilage, the arytenoid cartilages. The vocal ligaments are part of a tube, resembling an organ pipe, made of elastic tissue.…

  • Lumen Gentium (Roman Catholicism)

    Christianity: Fourth transition, from 1950: …Constitution on the Church” (Lumen Gentium; “Light of the Nations”), which insisted upon evangelization but presented a larger understanding of God’s grace for those outside the church, and urged missionaries to pursue dialogue.

  • Lumet, Sidney (American director)

    Sidney Lumet, American director who was noted for his psychological dramas, which typically featured characters wrestling with moral or emotional conflicts involving betrayal, corruption, or disillusionment. He was also known for eliciting strong performances from his cast members. Lumet grew up in

  • Lumi Labs (American company)

    Marissa Mayer: In 2018 Mayer cofounded Lumi Labs. The company was involved in “building consumer applications enabled by artificial intelligence.”

  • Lumière brothers (French inventors)

    Lumière brothers, French inventors and pioneer manufacturers of photographic equipment who devised an early motion-picture camera and projector called the Cinématographe (“cinema” is derived from this name). Auguste Lumière (b. October 19, 1862, Besançon, France—d. April 10, 1954, Lyon) and his

  • Lumière, Auguste (French inventor)

    Lumière brothers: …to Lyon set Louis and Auguste to work on the problem of combining animation with projection. Louis found the solution, which was patented in 1895. At that time they attached less importance to this invention than to improvements they had made simultaneously in colour photography. But on December 28, 1895,…

  • Lumière, Louis (French inventor)

    Lumière brothers: Louis worked on the problem of commercially satisfactory development of film; at 18 he had succeeded so well that with his father’s financial aid he opened a factory for producing photographic plates, which gained immediate success. By 1894 the Lumières were producing some 15 million…

  • Lumières, siècle de (European history)

    Enlightenment, a European intellectual movement of the 17th and 18th centuries in which ideas concerning God, reason, nature, and humanity were synthesized into a worldview that gained wide assent in the West and that instigated revolutionary developments in art, philosophy, and politics. Central

  • luminaire (lighting)

    Luminaire, Complete lighting unit, consisting of one or more lamps (bulbs or tubes that emit light), along with the socket and other parts that hold the lamp in place and protect it, wiring that connects the lamp to a power source, and a reflector that helps direct and distribute the light.

  • luminance (physics)

    colour: Tristimulus measurement and chromaticity diagrams: …their different Y values (luminance, or visually perceived brightness).

  • luminance signal (electronics)

    television: Basic principles of compatible colour: The NTSC system: …amplitude modulated by (1) the luminance signal, to represent changes in the intended luminance, and (2) the chrominance subcarrier, which in turn is amplitude modulated to represent changes in the intended saturation and phase modulated to represent changes in the intended hue. When a colour receiver is tuned to the…

  • luminance transmission (electronics)

    television: Basic principles of compatible colour: The NTSC system: …when viewing white light, the luminance transmission carries the impression of fine detail. Because it employs methods essentially identical to those of a monochrome television system, it can be picked up by black-and-white receivers. The chrominance transmission has no appreciable effect on black-and-white receivers, yet, when used with the luminance…

  • luminescence (physics)

    Luminescence, emission of light by certain materials when they are relatively cool. It is in contrast to light emitted from incandescent bodies, such as burning wood or coal, molten iron, and wire heated by an electric current. Luminescence may be seen in neon and fluorescent lamps; television,

  • luminescence, biological (chemical reaction)

    Bioluminescence, emission of light by an organism or by a laboratory biochemical system derived from an organism. It could be the ghostly glow of bacteria on decaying meat or fish, the shimmering radiance of protozoans in tropical seas, or the flickering signals of fireflies. The phenomenon occurs

  • luminescent lamp

    lamp: Modern electrical light sources: Luminescent lamps, which produce less heat than incandescent lamps, include electric discharge lamps, semiconductor lamps, and chemical lamps. Of the electric discharge lamps, the fluorescent lamp gives off a neutral white light, the sodium-vapour lamp emits a yellow-orange light, and the mercury-vapour lamp gives off…

  • luminiferous ether (theoretical substance)

    Ether, in physics, a theoretical universal substance believed during the 19th century to act as the medium for transmission of electromagnetic waves (e.g., light and X-rays), much as sound waves are transmitted by elastic media such as air. The ether was assumed to be weightless, transparent,

  • luminism (painting)

    Luminism, late 19th-century painting style emphasizing a unique clarity of light. It was characteristic of the works of a group of independent American painters who were directly influenced by the Hudson River school of painting. The term, however, was not coined until 1954 by John Baur, director

  • Luminodesmus sequoiae (millipede)

    bioluminescence: The range and variety of bioluminescent organisms: The entire body of Luminodesmus sequoiae, a millipede found in the Sierra Nevada mountains of California, glows with a diffuse light. Luminous insects include some true flies (order Diptera), notably Arachnocampa luminosa, the larva of which luminesces a greenish blue from a knob at the end of its body.…

  • luminol (chemical compound)

    luminescence: Early investigations: …nonbiological synthetic compounds such as luminol (with the formula 5-amino-2,3-dihydro-1.4-phthalazinedione). The strong blue chemiluminescence resulting from oxidation of this compound was first reported in 1928.

  • luminosity (astronomy)

    Luminosity, in astronomy, the amount of light emitted by an object in a unit of time. The luminosity of the Sun is 3.846 × 1026 watts (or 3.846 × 1033 ergs per second). Luminosity is an absolute measure of radiant power; that is, its value is independent of an observer’s distance from an object.

  • luminosity function (astronomy)

    Milky Way Galaxy: The stellar luminosity function: The stellar luminosity function is a description of the relative number of stars of different absolute luminosities. It is often used to describe the stellar content of various parts of the Galaxy or other groups of stars, but it most commonly refers…

  • luminous intensity (physics)

    Luminous intensity, the quantity of visible light that is emitted in unit time per unit solid angle. The unit for the quantity of light flowing from a source in any one second (the luminous power, or luminous flux) is called the lumen. The lumen is evaluated with reference to visual sensation. The

  • luminous moss (plant species)

    Luminous moss, (Schistostega pennata; formerly S. osmundacea), light-reflecting plant of the subclass Bryidae, native to the Northern Hemisphere. It forms green mats in caves, holes in wood or earth, or cavities between rocks or under tree roots. A luminous moss is about one centimetre (12 inch) or

  • luminous mysteries (religion)

    rosary: In Christianity: …set of mysteries, the “luminous mysteries,” or mysteries of light. The five new mysteries celebrate events in Jesus’ ministry, including his baptism; his miracle at Cana, where he turned water into wine; his proclamation of the kingdom of God; the Transfiguration, in which he revealed his divinity to three…

  • luminous paint

    Luminous paint, paint that glows in the dark because it contains a phosphor, a substance that emits light for a certain length of time after exposure to an energy source, such as ultraviolet radiation. Zinc sulfide and calcium sulfide are such phosphors. Some luminous paints contain a source of

  • luminous range (light)

    lighthouse: Geographic range and luminous range: The range at which a light can be seen depends upon atmospheric conditions and elevation. Since the geographic horizon is limited by the curvature of the Earth, it can be readily calculated for any elevation by standard geometric methods. In lighthouse work the observer is always…

  • Luminy (France)

    Marseille: Health: …centre in the suburb of Luminy links the region’s hospitals.

  • lumirhodopsin (protein)

    human eye: The transduction process: …°C (−220 °F) prelumirhodopsin becomes lumirhodopsin, with a slightly different colour; on warming further, successive changes are permitted until finally retinal is split off from the opsin to give a yellow solution. The important point to appreciate is that only at this stage is the chromatophore group split off; the…

  • Lumizip 900 (typesetter)

    printing: Second generation of phototypesetters: functional: The Lumizip 900 (1959) introduced a further revolutionary change by retaining as moving parts only the lens, which scans in a single movement the fixed series of light matrices so as to photograph at one time the whole line of 20 to 60 letters. Output reaches…

  • Lumley, Harry (American hockey player)

    Harry Lumley, American hockey goalie whose 16 seasons in the National Hockey League included an important role in the 1950 Stanley Cup victory of the Detroit Red Wings as well as selection to the All-Star team three times; he was inducted into the Hockey Hall of Fame in 1980 (b. Nov. 11, 1926, Owen

  • Lumley, Joanna (British actress)

    Joanna Lumley, British actress perhaps best known for her work in the television sitcom Absolutely Fabulous. Lumley was born in India, where her father had fought with the British army’s 6th Gurkha Rifles in World War II. During fierce fighting in Burma (Myanmar) in June 1944, his life was saved by

  • Lumley, Joanna Lamond (British actress)

    Joanna Lumley, British actress perhaps best known for her work in the television sitcom Absolutely Fabulous. Lumley was born in India, where her father had fought with the British army’s 6th Gurkha Rifles in World War II. During fierce fighting in Burma (Myanmar) in June 1944, his life was saved by

  • Lummis, Elizabeth Fries (American author)

    Elizabeth Fries Lummis Ellet, American historical writer, best remembered for her several extensive volumes of portraits of American women of the Revolutionary War and of Western pioneer days. Elizabeth Lummis began writing verse as a child. She was educated at the Female Seminary in Aurora, New

  • LUMO

    chemical bonding: Organometallic compounds: However, the lowest unfilled molecular orbital, the LUMO, has π symmetry and can accept electrons from an appropriate d orbital of the metal, and thus it can help the ligand to act as a Lewis acid. It is this ability of the ligand to act as both…

  • lump ore (mining)

    iron processing: Lumps and fines: As-mined iron ore contains lumps of varying size, the biggest being more than 1 metre (40 inches) across and the smallest about 1 millimetre (0.04 inch). The blast furnace, however, requires lumps between 7 and 25 millimetres, so the ore must…

  • lump-nosed bat (mammal)

    Long-eared bat, any of 19 species of small, usually colony-dwelling vesper bats (family Vespertilionidae). Long-eared bats are found in both the Old World and the New World (Plecotus) and in Australia (Nyctophilus). They are approximately 4–7 cm (1.6–2.8 inches) long, not including the 3.5–5.5-cm

  • lump-sum charter (transportation)

    charter party: …charter, bareboat charter, and “lump-sum” contract. The voyage charter is the most common. Under this method a ship is chartered for a one-way voyage between specific ports with a specified cargo at a negotiated rate of freight. On time charter, the charterer hires the ship for a stated period…

  • lump-sum contract (transportation)

    charter party: …charter, bareboat charter, and “lump-sum” contract. The voyage charter is the most common. Under this method a ship is chartered for a one-way voyage between specific ports with a specified cargo at a negotiated rate of freight. On time charter, the charterer hires the ship for a stated period…

  • Lumpaka (Jain sect)

    Jainism: Late medieval–early modern developments (1100–1800): …practice of image worship, the Lumpaka, or Lonka Gaccha, did not. Founded by the mid-15th-century layman Lonka Shah, the Lonka Gaccha denied the scriptural warranty of image worship and in the 17th century emerged as the non-image-worshipping Sthanakavasi sect. At the end of the 18th century, the Sthanakavasi underwent a…

  • lumpectomy (surgery)

    breast cancer: Treatment: A lumpectomy removes only the cancerous mass and a small amount of surrounding tissue; a simple mastectomy removes the entire breast; and a modified radical mastectomy removes the breast along with adjacent lymph nodes. Radical mastectomies involving removal of the breast, underlying muscle, and other tissue…

  • Lumpenproletariat (Marxism)

    Lumpenproletariat , (German: “rabble proletariat”), according to Karl Marx in The Communist Manifesto, the lowest stratum of the industrial working class, including also such undesirables as tramps and criminals. The members of the Lumpenproletariat—this “social scum,” said Marx—are not only

  • Lumpérica (work by Eltit)

    Latin American literature: Post-boom writers: …discussed novel is Lumpérica (1983; E. Luminata); it is a text laden with stylistic games and a vague plot. With Puerto Ricans Ana Lydia Vega and Rosario Ferré, Eltit became part of an established group of women Latin American writers who were quickly accepted into the Latin American canon.

  • lumpfish (fish)

    Lumpsucker, any of certain marine fish of the family Cyclopteridae (order Scorpaeniformes), found in cold northern waters. Lumpsuckers are thickset, short-bodied, scaleless fish with skins that are either smooth or studded with bony tubercles. Like the snailfish, which are often included in the

  • Lumphini Park (park, Thailand)

    Bangkok: History: …first and largest recreational area—Lumphini Park. During Rama VII’s reign (1925–35) municipal areas were delimited as part of a general administrative reorganization aimed at decentralization. In 1937 Bangkok was formally divided into the municipalities of Krung Thep and Thon Buri. At the time of their establishment, the two municipalities,…

  • Lumpkin, Grace (American author)

    American literature: Critics of society: …Call Home the Heart and Grace Lumpkin’s To Make My Bread (both 1932). Other notable proletarian novels included Jack Conroy’s The Disinherited (1933), Robert Cantwell’s The Land of Plenty (1934), and Albert Halper’s Union Square (1933), The Foundry (1934), and The Chute (1937), as well as some grim evocations of…

  • lumpsucker (fish)

    Lumpsucker, any of certain marine fish of the family Cyclopteridae (order Scorpaeniformes), found in cold northern waters. Lumpsuckers are thickset, short-bodied, scaleless fish with skins that are either smooth or studded with bony tubercles. Like the snailfish, which are often included in the

  • Lumumba, Patrice (Congolese politician)

    Patrice Lumumba, African nationalist leader, the first prime minister of the Democratic Republic of the Congo (June–September 1960). Forced out of office during a political crisis, he was assassinated a short time later. Lumumba was born in the village of Onalua in Kasai province, Belgian Congo. He

  • Lumumba, Patrice Hemery (Congolese politician)

    Patrice Lumumba, African nationalist leader, the first prime minister of the Democratic Republic of the Congo (June–September 1960). Forced out of office during a political crisis, he was assassinated a short time later. Lumumba was born in the village of Onalua in Kasai province, Belgian Congo. He

  • Lumut (Malaysia)

    Lumut, port, Peninsular (West) Malaysia, at the mouth of the Dindings River, on the Strait of Malacca. Lumut lies about 48 miles (77 km) southwest of the tin-mining town of Ipoh. It is the main town of the Dindings coastal area and the best sheltered deepwater port in Malaysia. A Royal Malaysian

  • Lun yü (Chinese text)

    Lunyu, (Chinese: “Conversations”) one of four texts of Confucianism that, when published together in 1190 by the Neo-Confucian philosopher Zhu Xi, became the great Chinese classic known as Sishu (“Four Books”). Lunyu has been translated into English as The Analects of Confucius. Lunyu is considered

  • Lun, John (British theatrical manager and actor)

    John Rich, English theatre manager and actor, the popularizer of English pantomime and founder of Covent Garden Theatre. Rich was a manager by inheritance; he received a three-quarter share in Lincoln’s Inn Fields Theatre from his father, Christopher Rich, in 1714, and, after running that house

  • Luna (space probe)

    Luna, any of a series of 24 unmanned Soviet lunar probes launched between 1959 and 1976. Luna 1 (launched Jan. 2, 1959) was the first spacecraft to escape Earth’s gravity. It failed to impact the Moon as planned and became the first man-made object to go into orbit around the Sun. Luna 2 (launched

  • Luna (Greek and Roman mythology)

    Selene, (Greek: “Moon”) in Greek and Roman religion, the personification of the moon as a goddess. She was worshipped at the new and full moons. According to Hesiod’s Theogony, her parents were the Titans Hyperion and Theia; her brother was Helios, the sun god (sometimes called her father); her

  • Luna (county, New Mexico, United States)

    Luna, county, southwestern New Mexico, U.S., bordered on the south by Mexico. It is a region of desert and semiarid plains broken by isolated mountains and mountain ranges, in the Mexican Highland section of the Basin and Range Province. The Continental Divide crosses the western section of the

  • Luna 25 (Russian spacecraft)

    Luna-Glob, (Russian: Moon-Globe) Russian uncrewed spacecraft that is designed to study the Moon. Luna-Glob consists of a probe that will land near the Moon’s south pole. It is scheduled for launch around

  • Luna de miel, luna de hiel (work by Pérez de Ayala)

    Ramón Pérez de Ayala: …miel, luna de hiel (1923; Moons of Honey and Gall) and its sequel, Los trabajos de Urbano y Simona (1923; “The Labours of Urbano and Simona”), treat the contrast between idealistic innocence and the realities of mature romantic love. In Tigre Juan (1926; Tiger Juan) and its sequel, El curandero…

  • luna e i falò, La (work by Pavese)

    Cesare Pavese: …luna e i falò (1950; The Moon and the Bonfires, 1950), is a bleak, yet compassionate story of a hero who tries to find himself by visiting the place in which he grew up. Several other works are notable, especially La bella estate (1949; in The Political Prisoner, 1955). Shortly…

  • luna moth (insect)

    Luna moth, Species (Actias luna) of saturniid moth of eastern North America. Lunas are pale green and have a wingspread of 4 in. (10 cm). The wings have a thin brown border, and each hind wing has a long tail-like projection. The larvae feed on the leaves of many kinds of trees and shrubs. See also

  • Luna, Álvaro de (constable of Castile)

    Álvaro de Luna, constable of Castile, ruler of Castile during much of the reign of the weak John II. Luna was the illegitimate son of a noble of Aragonese descent and the only distinguished statesman during a dismal period in Castilian history. He was a skilled politician, a farsighted legislator,

  • Luna, Pedro de (antipope)

    Benedict (XIII), antipope from 1394 to 1417. He reigned in Avignon, Provence, in opposition to the reigning popes in Rome, during the Western Schism (1378–1417), when the Roman Catholic Church was split by national rivalries claiming the papal throne. Of noble birth, he was professor of canon law

  • Luna-Glob (Russian spacecraft)

    Luna-Glob, (Russian: Moon-Globe) Russian uncrewed spacecraft that is designed to study the Moon. Luna-Glob consists of a probe that will land near the Moon’s south pole. It is scheduled for launch around

  • Luna-Resource (Russian spacecraft)

    Luna-Resource, Russian spacecraft that is designed to land on the Moon. Scheduled for launch about 2025, it will be Russia’s first mission to land on the Moon since the Luna 24 mission in August 1976. Luna-Resource weighs 1,250 kg (2,700 pounds). It is designed to study the effect of the solar wind

  • Lunacharsky, Anatoly (Russian author and educator)

    Anatoly Lunacharsky, Russian author, publicist, and politician who, with Maxim Gorky, did much to ensure the preservation of works of art during the civil war of 1918–20. Deported in 1898 for his revolutionary activities, Lunacharsky joined the Bolshevik group of the Social Democratic Party and

  • Lunacharsky, Anatoly Vasilyevich (Russian author and educator)

    Anatoly Lunacharsky, Russian author, publicist, and politician who, with Maxim Gorky, did much to ensure the preservation of works of art during the civil war of 1918–20. Deported in 1898 for his revolutionary activities, Lunacharsky joined the Bolshevik group of the Social Democratic Party and

  • Lunacy Act of 1845 (British history)

    Anthony Ashley Cooper, 7th earl of Shaftesbury: …he secured passage of the Lunacy Act of 1845, the first British statute to treat the insane as “persons of unsound mind” rather than social outcasts. He early was associated with the factory reform movement led by Richard Oastler and, in the House of Commons, by Michael Thomas Sadler. In…

  • Lunalilo (king of Hawaii)

    Kamehameha V: …elected a cousin, William Charles Lunalilo, to succeed him.

  • Lunalilo, William Charles (king of Hawaii)

    Kamehameha V: …elected a cousin, William Charles Lunalilo, to succeed him.

  • Lunar Atmosphere and Dust Environment Explorer (United States spacecraft)

    Lunar Atmosphere and Dust Environment Explorer (LADEE), U.S. spacecraft designed to study the thin lunar atmosphere and the amount of dust in it before it is altered by human activity on the Moon. LADEE, launched on September 6, 2013, was the first spacecraft based on the Modular Common Spacecraft

  • lunar calendar (chronology)

    Lunar calendar, any dating system based on a year consisting of synodic months—i.e., complete cycles of phases of the Moon. In every solar year (or year of the seasons), there are about 12.37 synodic months. Therefore, if a lunar-year calendar is to be kept in step with the seasonal year, a

  • lunar caustic (chemical compound)

    Silver nitrate, caustic chemical compound, important as an antiseptic, in the industrial preparation of other silver salts, and as a reagent in analytical chemistry. Its chemical formula is AgNO3. Applied to the skin and mucous membranes, silver nitrate is used either in stick form as lunar caustic

  • lunar crater (astronomy)

    Moon: Effects of impacts and volcanism: …are described by the term crater. The relative ages of lunar craters are indicated by their form and structural features. Young craters have rugged profiles and are surrounded by hummocky blankets of debris, called ejecta, and long light-coloured rays made by expelled material hitting the lunar surface. Older craters have…

  • Lunar Crater Observation and Sensing Satellite (United States spacecraft)

    LCROSS, U.S. spacecraft that was deliberately crashed into the Moon on October 9, 2009, resulting in the discovery of subsurface water. LCROSS was launched on June 18, 2009, from Cape Canaveral, Florida, on an Atlas rocket that also carried the Lunar Reconnaissance Orbiter (LRO), a spacecraft

  • lunar cycle (chronology)

    Metonic cycle, in chronology, a period of 19 years in which there are 235 lunations, or synodic months, after which the Moon’s phases recur on the same days of the solar year, or year of the seasons. The cycle was discovered by Meton (fl. 432 bc), an Athenian astronomer. Computation from modern

  • lunar daily variation (geomagnetics)

    geomagnetic field: The ionospheric dynamo: This variation is named the lunar daily variation, L. Its peak-to-peak amplitude is about 120 that of Sq.

  • lunar deity (religion)

    Lunar deity, any god or goddess related to or associated with the moon and its cycles. See moon

  • lunar eclipse (astronomy)

    eclipse: Lunar eclipse phenomena: The Moon, when full, may enter the shadow of Earth. The motion of the Moon around Earth is from west to east (see the figure of a lunar eclipse, in which the view of Earth is from above its North Pole). For…

  • lunar exploration

    space exploration: The race to the Moon: In the immediate aftermath of Gagarin’s orbital flight, President Kennedy was advised by NASA and by his vice president, Lyndon B. Johnson, of Braun’s belief that the Soviet Union, using Korolyov’s existing R-7 launcher, could well succeed in sending a multiperson…

  • lunar mansion (astronomy)

    astronomical map: Lunar mansions: Called hsiu in China and nakshatra in India, the lunar mansions are 28 divisions of the sky presumably selected as approximate “Moon stations” on successive nights. At least four quadrantal hsiu that divided the sky into quarters or quadrants were known in China…

  • Lunar Module (spacecraft)

    Apollo: …of the CSM was the lunar module (LM). One astronaut stayed in the CSM while the other two landed on the Moon in the LM. The LM had a descent stage and an ascent stage. The descent stage was left on the Moon, and the astronauts returned to the CSM…

  • Lunar New Year (festival)

    Lunar New Year, festival typically celebrated in China and other Asian countries that begins with the first new moon of the lunar calendar and ends on the first full moon of the lunar calendar, 15 days later. The lunar calendar is based on the cycles of the moon, so the dates of the holiday vary

  • lunar orbit rendezvous (space exploration)

    Apollo: In the method ultimately employed, lunar orbit rendezvous, a powerful launch vehicle (Saturn V rocket) placed a 50-ton spacecraft in a lunar trajectory. The spacecraft had three parts. The conical command module (CM) carried three astronauts. The service module (SM) was attached to the back of the CM and carried…

  • Lunar Orbiter (spacecraft)

    Lunar Orbiter, any of a series of five unmanned U.S. spacecraft placed in orbit around the Moon. Lunar Orbiter 1 was launched on Aug. 10, 1966; the last in the series, Lunar Orbiter 5, was launched on Aug. 1, 1967. The orbiters obtained 1,950 wide-angle and high-resolution photographs of much of

  • lunar parallax (astronomy)

    parallax: Lunar parallax: The first parallax determination was for the Moon, by far the nearest celestial body. Hipparchus (150 bce) determined the Moon’s parallax to be 58′ for a distance of approximately 59 times Earth’s equatorial radius, as compared with the modern value of 57′02.6″—that is,…

  • lunar phase (astronomy)

    number symbolism: …marks that possibly represent the phases of the Moon. The ancient Babylonians observed the movements of the planets, recorded them as numbers, and used them to predict eclipses and other astronomical phenomena. The priesthood of ancient Egypt used numbers to predict the flooding of the Nile. Pythagoreanism, a cult of…

  • Lunar Prospector (United States space probe)

    Lunar Prospector, U.S. space probe that studied the chemistry of the Moon’s surface. Lunar Prospector was launched on Jan. 6, 1998, by an Athena II rocket from Cape Canaveral, Florida. It entered lunar orbit on January 11 and achieved its final mapping orbit, 100 km (60 miles) high, four days

  • Lunar Reconnaissance Orbiter (United States spacecraft)

    Lunar Reconnaissance Orbiter (LRO), a U.S. spacecraft that mapped the surface of the Moon in order to help select ideal sites for uncrewed and eventually crewed lunar landers. After a series of postponements, the LRO was successfully launched on June 18, 2009, from Cape Canaveral, Florida, on an

  • Lunar Roving Vehicle (Apollo program)

    David Scott: Using the Lunar Roving Vehicle, they covered about 28 km (18 miles) on three separate treks and spent more than 17 hours outside their lunar module. The mission returned to Earth on August 7.

  • lunar science (science)

    geology: Astrogeology: Astrogeology is concerned with the geology of the solid bodies in the solar system, such as the asteroids and the planets and their moons. Research in this field helps scientists to better understand the evolution of the Earth in comparison with that of its…

  • Lunar Society (English intellectual group)

    Joseph Priestley: The chemistry of gases: …became a member of the Lunar Society, an elite group of local gentlemen, Dissenters, and industrialists (including Josiah Wedgwood, Erasmus Darwin, James Watt, and Matthew Boulton), who applied the principles of science and technology toward the solving of problems experienced in 18th-century urban life. When confronted by the multitude of…

  • lunar source rock

    Allende meteorite: …scientists in preparation for handling lunar rocks.

  • lunar tidal rhythm (biology)

    biological rhythm: A lunar tidal rhythm—the regular ebb and flow of oceans and very large inland bodies of water—subjects seashore plants and animals to a rhythmic change; typically two high and two low tides occur each day (about 24.8 hours). Many species of shorebirds exhibit this rhythm by…

  • lunar tide (astronomy)

    tide: Ocean tides: The tide-producing action of the Moon arises from the variations in its gravitational field over the surface of Earth as compared with its strength at Earth’s centre. The effect is that the water tends to accumulate on the parts of Earth’s surface directly toward and directly…

  • lunar year (chronology)

    year: A lunar year (used in some calendars) of 12 synodic months (12 cycles of lunar phases) is about 354 days long. A cosmic year is the time (about 225 million years) needed for the solar system to revolve once around the centre of the Milky Way…

  • Lunaria (plant genus)

    Honesty, (genus Lunaria), genus of three species of plants in the mustard family (Brassicaceae), native to Europe. Two of the species, annual honesty (Lunaria annua) and perennial honesty (L. rediviva), are widely grown for their fragrant flowers and papery seedpod partitions, which are used in

  • Lunaria annua (plant)

    honesty: Two of the species, annual honesty (Lunaria annua) and perennial honesty (L. rediviva), are widely grown for their fragrant flowers and papery seedpod partitions, which are used in dried-flower arrangements.

  • Lunaria rediviva (plant)

    honesty: …annual honesty (Lunaria annua) and perennial honesty (L. rediviva), are widely grown for their fragrant flowers and papery seedpod partitions, which are used in dried-flower arrangements.

  • Lunaria telekiana (plant)

    honesty: Lunaria telekiana is a rare plant endemic to the mountains of Albania, Montenegro, and Serbia.

  • Your preference has been recorded
    Check out Britannica's new site for parents!
    Subscribe Today!