Galle, Johann Gottfried (1812–1910
(Galle, Johann Gottfried (1812–1910
German astronomer who, with Heinrich Louis d'Arrest, made the first observation of Neptune (1846) based on calculations by Leverrier. Though Galle was the first to observe Neptune, its discovery is usually credited to John Adams (who made an earlier calculation) and Leverrier. Galle also discovered the crêpe ring of Saturn (1838) and suggested a method for determining the scale of the Solar System based on the observation of asteroids.
(Kuiper, Gerard Peter (1905–1973
(Kuiper, Gerard Peter (1905–1973
Dutch-born American astronomer and graduate of the University of Leiden, who worked at the Yerkes Observatory and later at the McDonald Observatory. His name rhymes with "viper". Early in his career, Kuiper studied binary star and multiple star systems. His observations led him to conclude in 1935 that the average separation between the components of binary stars was about 20 AU, which is similar to the distance of the gas giants from the Sun. Following renewed difficulties with the catastrophic hypothesis of planetary formation, Kuiper speculated in 1951 that "it almost looks as though the solar system is a degenerate double star, in which the second mass did not condense into a single star but was spread out – and formed the planets and comets." Extrapolating from the fact that about 10% of binaries contained companion stars that were one-tenth or less as massive as the primaries, Kuiper suggested there might be 100 billion planetary systems in our Galaxy alone.
Kuiper's spectroscopic studies led to the discovery of the atmosphere of Titan (1944) and features, afterward known as Kuiper bands, in the spectra of Uranus and Neptune, due to methane. He discovered Uranus's moon Miranda (1948) and Neptune's moon Nereid (1949). He also detected carbon dioxide in the martian atmosphere (1947) and suggested that lichenlike planets might exist on the martian surface .
(Van Allen, James Alfred (1914–2006
(Van Allen, James Alfred (1914–2006
American space scientist who contributed to 24 satellite and space probe missions, including some of the early Explorers and pioneers 10 and 11. His research focused on planetary magnetospheres and the solar wind. He began high-altitude rocket research in 1945, initially used captured V-2s, and is best remembered for his discovery of the radiation belts that were subsequently named after him .
Van Allen received a BS from Iowa Wesleyan College in 1935, and a M.S. (1936) and Ph.D. (1939) from the California Institute of Technology. After a spell with the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, where he studied photodisintegration, Van Allen moved in 1942 to the Applied Physics Laboratory at The Johns Hopkins University where he worked to develop a rugged vacuum tube. He also helped to develop proximity fuses for weapons used in World War II, especially for torpedoes used by the United States Navy. By the fall of 1942, he had been commissioned as an officer in the Navy and was sent to the Pacific to field test and complete operational requirements for the proximity fuses. After the War, Van Allen returned to civilian life and began working in high altitude research, first for the Applied Physics Laboratory and, after 1950, at the University of Iowa. Van Allen's career took an important turn in 1955 when he and several other American scientists developed proposals for the launch of a scientific satellite as part of the research program conducted during the International Geophysical Year (IGY) of 1957–58. After the success of the Soviet Union with Sputnik 1, Van Allen's Explorer spacecraft was approved for launch on a Redstone rocket. It flew on January 31,1958, and returned enormously important scientific data about the radiation belts circling the Earth. Van Allen became a celebrity because of the success of that mission, and went on to other important scientific projects in space. In various ways, he was involved in the first four Explorer probes, the first Pioneers, several Mariner projects and the Orbiting Geophysical Observatory Van Allen retired from the University of Iowa in 1985 to become Carver Professor of Physics, Emeritus, after having served as the head of the Department of Physics and Astronomy from 1951.
(Joy, Alfred Harrison (1883–1973
(Joy, Alfred Harrison (1883–1973
American astronomer best known for his work on stellar distances, the radial motions of stars, and variable stars. After teaching astronomy for a number of years and spending a year at Yerkes Observatory, Joy came to Mount Wilson Observatory in 1915. There he applied Walter Adams's method of spectroscopic parallax to determine the distances of thousands of stars. When he retired nearly half of all published radial velocities of stars had been found at Mount Wilson, largely through his efforts. His measurements of the radial velocities of Cepheid Variables confirmed the distance and direction of the galactic center and the Sun's rate of revolution about it. He also invented the classification of T Tauri stars and made extensive studies of them. Although he officially retired in 1948, Joy remained active at Mount Wilson for a total of nearly 66 years.
(Bappu, (Manali Kallat) Vainu (1927–1982
(Bappu, (Manali Kallat) Vainu (1927–1982
Prominent Indian astronomer who did much to set up new observatories and astronomical research centers in his native country. His father was an assistant at the Nizamiah Observatory in Hyderabad, so that Bappu was exposed to astronomy from an early age. He won a scholarship to Harvard and co-discovered a comet, named Bappu-Bok-Newkirk, shortly after his arrival. Later he went to the Palomar Observatory where he and Colin Wilson discovered a relationship, now known as the Wilson-Bappu effect, between the luminosity of certain kinds of stars and some of their spectral characteristics. In 1953, he returned to India and worked at the Uttar Pradesh State Observatory before becoming director of the observatory at Kodaikanal, the oldest in India. He helped establish the Indian Institute of Astrophysics at Bangalore and set up the largest telescope in India, a 2.34-meter reflector at the Kavalur Observatory – an instrument named in his honor in 1986.
(Digges, Leonard (c.1520–c.1559) and Thomas (c.1545–1595
(Digges, Leonard (c.1520–c.1559) and Thomas (c.1545–1595
English father and son who pioneered the construction of the telescope (Leonard) and its use (Thomas). Leonard Digges was educated at Oxford and made his name as a mathematician, a surveyor, and an author of several books. He invented a reflecting telescope a century before Isaac Newton, and may also have built a refracting telescope.
Thomas was only 13 when his father died but had John Dee, a mathematician, as his guardian. In 1571, Thomas published a mathematical work of his own and a posthumous book, Pantometria, by his father in which Leonard's invention of the telescope is discussed. Thomas's observations of the supernova of 1572 were used by Tycho Brahe in his analysis of this event. Thomas was also the first to promote in Britain the heliocentric view of the solar system due to Copernicus. He was also a pioneer of the enlarged, stellar universe, maintaining that the stars, instead of being fixed to a crystalline sphere, were other suns lying at great distances. However, although he helped pave the way for others, like Huygens, to contemplate the possibility of extrasolar planets and life, he continued to regard the Sun as special and centrally located in the Universe. It has been suggested that Digges may have met Giordano Bruno during the latter's stay in England and derived some of his ideas from the Italian.