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Jaan Einasto
Jaan Einasto (born 23 February 1929) is an Estonian astrophysicist and one of the discoverers of the large-scale structure of the Universe. Family and early life Born Jaan Eisenschmidt in Tartu, the name "Einasto" is an anagram of "Estonia" (it was chosen by his patriotic father in the 1930s to replace the family's German name). Einasto married and had 3 children, 2 daughters and the youngest, a son. His daughter, Maret, is also an astrophysicist, who collaborates with her father. Education and career He attended the University of Tartu, where he received the Ph.D. equivalent in 1955 and a senior research doctorate in 1972. From 1952, he has worked as a scientist at the Tartu Observatory (1977–1998) Head of the Department of Cosmology; from 1992–1995, he was Professor of Cosmology at the University of Tartu. For a long time, he was Head of the Division of Astronomy and Physics of the Estonian Academy of Sciences in Tallinn. Einasto is a member of the Academia Europaea, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tartu
Tartu is the second largest city in Estonia after Tallinn. Tartu has a population of 97,759 (as of 2024). It is southeast of Tallinn and 245 kilometres (152 miles) northeast of Riga, Latvia. Tartu lies on the Emajõgi river, which connects the two largest lakes in Estonia, Lake Võrtsjärv and Lake Peipus. From the 13th century until the end of the 19th century, Tartu was known in most of the world by variants of its historical name Dorpat. Tartu, the largest urban centre of southern Estonia, is often considered the "intellectual capital city" of the country, especially as it is home to the nation's oldest and most renowned university, the University of Tartu (founded in 1632). Tartu also houses the Supreme Court of Estonia, the Ministry of Education and Research (Estonia), Ministry of Education and Research, the Estonian National Museum, and the oldest Estonian-language theatre, Vanemuine. It is also the birthplace of the Estonian Song Festivals. Tartu was designated as the E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academia Europaea
The Academia Europaea is a pan-European Academy of humanities, letters, law, and sciences. The Academia was founded in 1988 as a functioning Europe-wide Academy that encompasses all fields of scholarly inquiry. It acts as co-ordinator of European interests in national research agencies. History The concept of a 'European Academy of Sciences' was raised at a meeting in Paris of the European Ministers of Science in 1985. The initiative was taken by the Royal Society (United Kingdom) which resulted in a meeting in London in June 1986 of Arnold Burgen (United Kingdom), Hubert Curien (France), Umberto Colombo (Italy), David Magnusson (Sweden), Eugen Seibold (Germany) and Ruurd van Lieshout (the Netherlands) – who agreed to the need for a new body. The meeting also included Brian Flowers and John Kendrew. Another, larger meeting took place in October 1986 with participants representing some countries in the Council of Europe and was in support for the development of a Eur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tõravere Observatory
The Tartu Observatory () is the largest astronomical observatory in Estonia. On 1 January 2018, Tartu Observatory was joined again to the University of Tartu, and the observatory is now an institute of the university. It is located on the Tõravere hill, about 20 km south-west of Tartu in Nõo Parish, Tartu County. The old Tartu Observatory, located in Tartu city centre, is known internationally for its connection to Friedrich Georg Wilhelm von Struve and the Struve Geodetic Arc, of which it is the first reference point. History The Tartu Observatory was founded at the Imperial University of Dorpat as it was reopened in 1802. The observatory building was completed in 1810 on the Toome hill in Dorpat. The instruments were installed in 1814 by von Struve who subsequently started observations. In 1824, a 9" Fraunhofer refractor arrived, the largest achromatic telescope in the world at the time. When von Struve began assembling his Geodetic Arc in 1816, the doorstep of the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Curves
The rotation curve of a disc galaxy (also called a velocity curve) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their Polar coordinate system, radial distance from that galaxy's centre. It is typically rendered graphically as a Plot (graphics), plot, and the data observed from each side of a spiral galaxy are generally asymmetric, so that data from each side are averaged to create the curve. A significant discrepancy exists between the experimental curves observed, and a curve derived by applying gravity theory to the matter observed in a galaxy. Theories involving dark matter are the main postulated solutions to account for the variance. The rotational/orbital speeds of galaxies/stars do not follow the rules found in other orbital systems such as stars/planets and planets/moons that have most of their mass at the centre. Stars revolve around their galaxy's centre at equal or increasing speed over a large range of distances. In contrast, the orbit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vera Rubin
Vera Florence Cooper Rubin (; July 23, 1928 – December 25, 2016) was an American astronomer who pioneered work on galaxy rotation rates. She uncovered the discrepancy between the predicted and observed angular motion of galaxies by studying galactic rotation curves. Her work on the galaxy rotation problem was cited by others as evidence for the existence of dark matter. Honored throughout her lifetime for her work, she received the Bruce Medal, the Gold Medal of the Royal Astronomical Society, and the National Medal of Science, among others. The Vera C. Rubin Observatory in Chile is named in her honor. Her legacy is described by ''The New York Times'' as "ushering in a Copernican-scale change" in cosmological theory. Rubin is widely regarded as having been one of the select women in science who were overlooked for the Nobel Prize on the basis of gender discrimination. Rubin spent her life advocating for women in science, and was known for her mentorship of aspiring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Einasto Profile
The Einasto profile (or Einasto model) is a mathematical function that describes how the density \rho of a spherical stellar system varies with distance r from its center. Jaan Einasto introduced his model at a 1963 conference in Alma-Ata, Kazakhstan. The Einasto profile possesses a power law logarithmic slope of the form: \gamma(r) \equiv -\frac \propto r^ which can be rearranged to give \rho(r) \propto \exp . The parameter \alpha controls the degree of curvature of the profile. This can be seen by computing the slope on a log-log plot: \frac \propto -r^ . The larger \alpha, the more rapidly the slope varies with radius (see figure). Einasto's law can be described as a generalization of a power law, \rho\propto r^, which has a constant slope on a log-log plot. Einasto's model has the same mathematical form as Sersic's law, which is used to describe the surface brightness (i.e. projected density) profile of galaxies, except that the Einasto model describes a spherically symmet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy 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, which is part of the Pisces–Cetus Supercluster Complex. 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 The existence of superclusters indicates that the galaxies in the Universe are not uniformly distributed; most of them are drawn together in groups and clusters, with groups containing up to some dozens of galaxies and clusters up to several thousand galaxies. Those groups and clusters and additional isolated galaxies in turn form even larger structures called superclusters. Their existence was f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Einasto Supercluster
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Einasto may refer to: People * Jaan Einasto (born 1929), Estonian astrophysicist Astronomy * Einasto Supercluster, a supercluster of galaxies, the most massive supercluster known in the Universe at the time of its discovery in 2023, named for Jaan Einasto * 11577 Einasto, the asteroid Einasto, a main-belt asteroid, the 11577th asteroid discovered, named after Jaan Einasto Other uses * Einasto profile, a mathematical function that describes how the density of a stellar spherical system varies with distance from the center See also * * Einsatz * Estonia (other) Estonia is a country in Northern Europe. The same country, or larger part of it, has also been referred to as: * Danish Estonia, a dominion of Denmark (1219–1346) * Swedish Estonia, a dominion of Sweden (1561–1721) * Governorate of Estonia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics Today
''Physics Today'' is the membership magazine of the American Institute of Physics. First published in May 1948, it is issued on a monthly schedule, and is provided to the members of ten physics societies, including the American Physical Society. It is also available to non-members as a paid annual subscription. The magazine informs readers about important developments in overview articles written by experts, shorter review articles written internally by staff, and also discusses issues and events of importance to the science community in politics, education, and other fields. The magazine provides a historical resource of events associated with physics. For example it discussed debunking the physics of the Star Wars program of the 1980s, and the state of physics in China and the Soviet Union during the 1950s and 1970s. According to the ''Journal Citation Reports'', the journal has a 2017 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic jou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter
In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relativity unless more matter is present than can be observed. Such effects occur in the context of Galaxy formation and evolution, formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background Anisotropy, anisotropies. Dark matter is thought to serve as gravitational scaffolding for cosmic structures. After the Big Bang, dark matter clumped into blobs along narrow filaments with superclusters of galaxies forming a cosmic web at scales on which entire galaxies appear like tiny particles. In the standard Lambda-CDM model of cosmology, the mass–energy equivalence, mass–energy content o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
