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Shapley-Ames Catalog
The ''Shapley-Ames Catalog of Bright Galaxies'' is a catalog of galaxies published in 1932 that includes observations of 1249 objects brighter than 13.2 magnitude. It was compiled by Harlow Shapley and Adelaide Ames. They identified 1189 objects based on the New General Catalogue and 48 based on the Index Catalogue. With the help of new photographic recordings, which also contained comparison stars of known brightness, the brightness of many galaxies were measured and recorded only up to a magnitude of 13.2. It was the first compilation of bright galaxies in the northern and southern sky. The catalog contains position, brightness, size, and Hubble classification of the galaxies. For the next 60 years, astronomers referred to this catalog as a primary source for information about redshifts and galaxy types. History Shapley and Ames began their study of all nearby galaxies in 1926. An important finding from this research was that the galaxies were not evenly distributed (they violated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxies
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many are thought to have supermassive black holes at their centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harlow Shapley
Harlow Shapley (November 2, 1885 – October 20, 1972) was an American scientist, head of the Harvard College Observatory (1921–1952), and political activist during the latter New Deal and Fair Deal. Shapley used Cepheid variable stars to estimate the size of the Milky Way Galaxy and the Sun's position within it by using parallax.Bart J. Bok. Harlow Shapely 1885–1972 A Biographical Memoir. National Academy of Sciences In 1953 he proposed his "liquid water belt" theory, now known as the concept of a habitable zone.Richard J. Hugget, ''uGeoecology: an evolutionary approach''. p. 10 Background Shapley was born on a farm five miles outside Nashville, Missouri, to Willis and Sarah (née Stowell) Shapley. He went to school in Jasper, Missouri, but not beyond elementary school. He worked as a journalist after studying at home and covering crime stories as a newspaper reporter for the ''Daily Sun'' in Chanute, Kansas, and intermittently for the ''Times'' of Joplin, Missouri. In Chanu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adelaide Ames
Adelaide Ames (June 3, 1900 – June 26, 1932) was an American astronomer and research assistant at Harvard University. She contributed to the study of galaxies with her co-authorship of ''A Survey of the External Galaxies Brighter Than the Thirteenth Magnitude'', which was later known as the Shapley-Ames catalog.''Research Astronomer Lost by Drowning.'' In: ''Popular astronomy'', Vol. 40, August/September 1932, S. 448–449.online Ames was a member of the American Astronomical Society. She was a contemporary of Cecilia Payne-Gaposchkin and her closest friend at the observatory.Barbara L. Welther: ''Adelaide Ames and the Shapley-Ames Catalogue''. (Abstract) In: Bulletin of the American Astronomical Society. Vol. 22, 1990, S. 841.online Ames died in a boating accident in 1932, the same year the Shapley-Ames catalog was published. She was interred at the Arlington National Cemetery. Biography Ames attended Vassar College until 1922 and then studied at Radcliffe College, where there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulentic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a negative redshift, or blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. In astronomy and cosmology, the three main causes of electromagnetic redshift are # The radiation travels between objects which are moving apart (" relativistic" redshift, an example of the relativistic Doppler effect) #The radiation travels towards an object in a weaker gravitational potential, i.e. towards an object in less strongly curved (flatter) spacetime (gravitational redshift) #The radiation travels through expanding space (cosmological redshift). The observation that all sufficiently distant light sources show redshift corresponding to their distance from Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotropy
Isotropy is uniformity in all orientations; it is derived . Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix ' or ', hence ''anisotropy''. ''Anisotropy'' is also used to describe situations where properties vary systematically, dependent on direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. Mathematics Within mathematics, ''isotropy'' has a few different meanings: ; Isotropic manifolds: A manifold is isotropic if the geometry on the manifold is the same regardless of direction. A similar concept is homogeneity. ; Isotropic quadratic form: A quadratic form ''q'' is said to be isotropic if there is a non-zero vector ''v'' such that ; such a ''v'' is an isotropic vector or null vector. In complex geometry, a line through the origin in the direction of an isotropic vector is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University Press
Stanford University Press (SUP) is the publishing house of Stanford University. It is one of the oldest academic presses in the United States and the first university press to be established on the West Coast. It was among the presses officially admitted to the Association of American University Presses (now the Association of University Presses) at the organization's founding, in 1937, and is one of twenty-two current member presses from that original group. The press publishes 130 books per year across the humanities, social sciences, and business, and has more than 3,500 titles in print. History David Starr Jordan, the first president of Stanford University, posited four propositions to Leland and Jane Stanford when accepting the post, the last of which stipulated, “That provision be made for the publication of the results of any important research on the part of professors, or advanced students. Such papers may be issued from time to time as ‘Memoirs of the Leland Stanf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercluster
A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in turn is part of the Virgo Supercluster, which is part of the Laniakea Supercluster."Earth's new address: 'Solar System, Milky Way, Laniakea ''Nature (journal), Nature'' The large size and low density of superclusters means that they, unlike clusters, expand with the Hubble expansion. The number of superclusters in the observable universe is estimated to be 10 million. Existence [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allan Sandage
Allan Rex Sandage (June 18, 1926 – November 13, 2010) was an American astronomer. He was Staff Member Emeritus with the Carnegie Observatories in Pasadena, California. He determined the first reasonably accurate values for the Hubble constant and the age of the universe. Career Sandage was one of the most influential astronomers of the 20th century. He was born in Iowa City, Iowa, United States. He graduated from the University of Illinois in 1948. In 1953 he received a PhD from the California Institute of Technology; the German-born Wilson Observatory-based astronomer Walter Baade was his advisor. During this time Sandage was a graduate student assistant to cosmologist Edwin Hubble. He continued Hubble's research program after Hubble died in 1953. In 1952 Baade surprised his fellow astronomers by announcing (at the 1952 Conference of the International Astronomical Union, in Rome) his determination of two separate populations of Cepheid variable stars in the Andromeda Ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustav Tammann
Gustav Andreas Tammann (24 July 1932 – 6 January 2019) was a German astronomer and academic. He served as director of the Astronomical Institute of the University of Basel; as a member of the European Space Agency Space Telescope Advisory Team, and as Member of Council of the European Southern Observatory. His research interests include supernovae and the extragalactic distance scale. Tammann was a former President of the International Astronomical Union Commission on Galaxies. Education and early career Tammann studied astronomy in Basel, Switzerland and Göttingen, Germany. In 1963 he began a longtime working relationship with Allan Sandage at the Mount Wilson and Palomar observatories. Academic career In 1972 he became a professor at the University of Hamburg. From 1977 until his retirement, he was a professor and head of the Astronomical Institute at the University of Basel. Tammann is the grandson of the physical chemist Gustav Tammann. Accolades In 1991 Tammann b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
