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Gerard Kuiper
Gerard Peter Kuiper (; ; born Gerrit Pieter Kuiper; 7 December 1905 – 23 December 1973) was a Dutch astronomer, planetary scientist, selenographer, author and professor. He is the eponymous namesake of the Kuiper belt. Kuiper is considered by many to be the father of modern planetary science. Early life and career Kuiper, the son of a tailor in the village of Tuitjenhorn in North Holland, had an early interest in astronomy. He had extraordinarily sharp eyesight, allowing him to see with the naked eye magnitude 7.5 stars, about four times fainter than those visible to normal eyes. He studied at Leiden University in 1924, where at the time a very large number of astronomers had congregated. He befriended fellow students Bart Bok and Pieter Oosterhoff, and was taught by Ejnar Hertzsprung, Antonie Pannekoek, Willem de Sitter, Jan Woltjer, Jan Oort, and the physicist Paul Ehrenfest. He received his candidate degree in Astronomy in 1927 and continued straig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicolaas Kuiper
Nicolaas Hendrik Kuiper (; 28 June 1920 – 12 December 1994) was a Dutch mathematician, known for Kuiper's test and proving Kuiper's theorem. He also contributed to the Nash embedding theorem. Kuiper studied at University of Leiden in 1937-41, and worked as a secondary school teacher of mathematics in Dordrecht in 1942-47. He completed his Ph.D. in differential geometry from the University of Leiden in 1946 under the supervision of Willem van der Woude. In 1947 he came to the United States at the invitation of Oscar Veblen, where he stayed at the Institute for Advanced Study for one year as Veblen's assistant, and the second year as member of the IAS, meeting Shiing-Shen Chern, and he also went to the University of Michigan at Ann Arbor. In February to June 1954, he went for a second time to Ann Arbor where he met Raoul Bott and his student Stephen Smale. In 1950 he was appointed professor of mathematics (and statistics) at the Agricultural University of Wageningen. In 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard College Observatory
The Harvard College Observatory (HCO) is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, United States, and was founded in 1839. With the Smithsonian Astrophysical Observatory, it forms part of the Center for Astrophysics Harvard & Smithsonian. HCO houses a collection of approximately 500,000 astronomical plates taken between the mid-1880s and 1989 (with a gap from 1953–1968). This 100-year coverage is a unique resource for studying temporal variations in the universe. The Digital Access to a Sky Century @ Harvard project is digitally scanning and archiving these photographic plates. History In 1839, the Harvard Corporation voted to appoint William Cranch Bond, a prominent Boston clockmaker, as "Astronomical Observer to the University" (at no salary). This marked the founding of the Harvard College Observatory. HCO's first tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lick Observatory
The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by the University of California Observatories, with headquarters on the University of California, Santa Cruz campus, where its scientific staff moved in the mid-1960s. It is named after James Lick. The first new moon of Jupiter to be identified since the time of Galileo was discovered at this observatory; Amalthea, the planet's fifth moon, was discovered at this observatory in 1892. Early history Lick Observatory is the world's first permanently occupied mountain-top observatory. The observatory, in a Classical Revival style structure, was constructed between 1876 and 1887, from a bequest from James Lick of $700,000, . Lick, originally a carpenter and piano maker, had arrived from Peru in San Francisco, California, in late 1847; after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Grant Aitken
Robert Grant Aitken (December 31, 1864 – October 29, 1951) was an American astronomer. Early life and education Robert Grant Aitken was born in Jackson, California, to Scottish immigrant Robert Aitken and Wilhelmina Depinau. Aitken attended Williams College in Massachusetts and graduated with an undergraduate degree in 1887. Career From 1887–1891, he worked as a mathematics instructor at Livermore, California, then received his M.A. from Williams College in 1892. He became a professor of mathematics at the College of the Pacific, another liberal arts school. He was offered an assistant astronomer position at Lick Observatory in California in 1895. He began a systematically study of double stars, measuring their positions and calculating their orbits around one another. From 1899, in collaboration with W. J. Hussey, he methodically created a very large catalog of such stars. This ongoing work was published in Lick Observatory bulletins. In 1905, Hussey left and A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Star
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candidate (degree)
Candidate (Latin ''candidatus'' or ''candidata'') is the name of various academic degrees, chiefly in Scandinavia, the Soviet Union, the Netherlands and Belgium. In Scandinavia, it is a higher professional-level degree usually corresponding to 5–7 years of studies, whereas in the Soviet states, it was a research degree roughly equivalent to the American Doctor of Philosophy degree. In the Netherlands and Belgium, it was an undergraduate first-cycle degree roughly comparable with the bachelor's degree. The term is derived from Latin ''candida'', meaning white. In Ancient Rome, men running for political office would usually wear togas chalked and bleached to be bright white at speeches, debates, conventions, and other public functions. The term ''candidate'' thus came to mean someone who seeks an office of some sort. Scandinavia In Scandinavia, the term was introduced in the early 18th century and referred to the higher degrees in theology, law and medicine. A candidate's degree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Ehrenfest
Paul Ehrenfest (18 January 1880 – 25 September 1933) was an Austrian theoretical physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition and the Ehrenfest theorem. He bonded with Albert Einstein on a visit to Prague in 1912 and became a professor in Leiden, where he frequently hosted Einstein. Biography Paul Ehrenfest was born and grew up in Vienna to Jewish parents from Loštice in Moravia (now part of the Czech Republic). His parents, Sigmund Ehrenfest and Johanna Jellinek, ran a grocery store. Although the family was not overly religious, Paul studied Hebrew and the history of the Jewish people. Later, he always emphasized his Jewish roots. Ehrenfest excelled in grade school but did not do well at the Akademisches Gymnasium, his best subject being mathematics. After transferring to the Franz Josef Gymnasium, his marks improved. In 1899, he passed the final exams. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Oort
Jan Hendrik Oort ( or ; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy. His ''New York Times'' obituary called him "one of the century's foremost explorers of the universe"; the European Space Agency website describes him as "one of the greatest astronomers of the 20th century" and states that he "revolutionised astronomy through his ground-breaking discoveries." In 1955, Oort's name appeared in ''Life'' magazine's list of the 100 most famous living people. He has been described as "putting the Netherlands in the forefront of postwar astronomy." Oort determined that the Milky Way rotates and overturned the idea that the Sun was at its center. He also postulated the existence of the mysterious invisible dark matter in 1932, which is believed to make up roughly 84.5% of the total matter in the Universe and whose gravitational pull causes "the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan Woltjer (astronomer)
Jan Woltjer (3 August 1891, Amsterdam – 28 January 1946, Leiden) was a Dutch astronomer. Woltjer was the son of the classical scholar Jan Woltjer. On 13 December 1916 he married Hillegonda de Vries in Groningen. He worked and taught at Leiden University, where Gerard P. Kuiper was one of his students. He was the father of the astronomer Lodewijk Woltjer (1930–2019), who was the director general of the European Southern Observatory from 1975 to 1987. The crater Woltjer on the Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ... and the asteroid 1795 Woltjer are both named after him. References External links Website Leiden professors 1891 births 1946 deaths 20th-century Dutch astronomers Academic staff of Leiden University Scientists from Amsterdam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonie Pannekoek
Antonie “Anton” Pannekoek (; 2 January 1873 – 28 April 1960) was a Dutch astronomer, philosopher, Marxist theorist, and socialist revolutionary. He was one of the main theorists of council communism (Dutch: ''radencommunisme''). Biography Pannekoek studied mathematics and physics in Leiden from 1891. Even before he went to college he was interested in astronomy and studied the Milky Way and variability of Polaris. He published his first article, ''On the Necessity of Further Researches on the Milky Way'', as a student. He briefly worked as a geodesist before he returned to the Leiden Observatory (''Leidse Sterrewacht'') to work as an observer and write his thesis on the variability of Algol. After reading Edward Bellamy's '' Equality'', Pannekoek became a convinced socialist and started studying the philosophies of Karl Marx and Joseph Dietzgen. Soon Pannekoek became a well-known Marxist writer, writing for both Dutch and German socialist magazines, like '' Die Neue Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
