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Scott Tremaine
Scott Duncan Tremaine (born 1950) is a Canadian-born astrophysicist. He is a fellow of the Royal Society of London, the Royal Society of Canada and the National Academy of Sciences. Tremaine is widely regarded as one of the world's leading astrophysicists for his contributions to the theory of Solar System and galactic dynamics. Tremaine is the namesake of asteroid 3806 Tremaine. He is credited with coining the name " Kuiper belt". Career He obtained a bachelor's degree at McMaster University in 1971, and a PhD from Princeton University in 1975. He further received an honorary PhD from McMaster University in 1996. He was an associate professor at the Massachusetts Institute of Technology from 1981 to 1985. He became the first director of the Canadian Institute for Theoretical Astrophysics at the University of Toronto in 1986, a position he held until 1996. He gained the rare distinction of "University Professor" at the University of Toronto in 1995. In 1997, he left CITA and ...
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Toronto
Toronto ( ; or ) is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the anchor of the Golden Horseshoe, an urban agglomeration of 9,765,188 people (as of 2021) surrounding the western end of Lake Ontario, while the Greater Toronto Area proper had a 2021 population of 6,712,341. Toronto is an international centre of business, finance, arts, sports and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world. Indigenous peoples have travelled through and inhabited the Toronto area, located on a broad sloping plateau interspersed with rivers, deep ravines, and urban forest, for more than 10,000 years. After the broadly disputed Toronto Purchase, when the Mississauga surrendered the area to the British Crown, the British established the town of York in 1793 and later designat ...
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Massachusetts Institute Of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the most prestigious and highly ranked academic institutions in the world. Founded in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. MIT is one of three private land grant universities in the United States, the others being Cornell University and Tuskegee University. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River, and encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory, the Bates Center, and the Haystack Observatory, as well as affiliated laboratories such as the Broad and Whitehead Institutes. , 98 ...
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Prometheus (moon)
Prometheus is an inner satellite of Saturn. It was discovered in 1980 (on October 24) from photos taken by the ''Voyager 1'' probe, and was provisionally designated . In late 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated . Prometheus is extremely elongated, measuring approximately . It has several ridges and valleys and a number of impact craters of about diameter are visible, but it is less cratered than nearby Pandora, Epimetheus, and Janus. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body. There is much uncertainty in these values, however, and so this remains to be confirmed. Interactions with F Ring and other moons Prometheus is a shepherd satellite for the inner edge of Saturn's narrow F Ring. Pandora orbits just outside the F Ring, and has traditionally been viewed as an outer shepherd of the ring; however, recent studies indicate that only Prometheus con ...
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Uranus
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather of Zeus (Jupiter (mythology), Jupiter) and father of Cronus (Saturn (mythology), Saturn). It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as "ice giants" to distinguish them from the other giant planets. As with gas giants, ice giants also lack a well defined "solid surface." Uranus's Atmosphere#Others, atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more "volatiles, ices" such as water, ammonia, and methane, al ...
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Rings Of Saturn
The rings of Saturn are the most extensive ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometers to meters, that orbit around Saturn. The ring particles are made almost entirely of water ice, with a trace component of rocky material. There is still no consensus as to their mechanism of formation. Although theoretical models indicated that the rings were likely to have formed early in the Solar System's history, newer data from '' Cassini'' suggested they formed relatively late. Although reflection from the rings increases Saturn's brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. The concept that Saturn's rin ...
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Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. Saturn's interior is most likely composed of a core of iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The outer atmosphere is g ...
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Shepherd Moon
A shepherd moon (also herder moon or watcher moon) is a small natural satellite that clears a gap in planetary-ring material or keeps particles within a ring contained. The name is a result of the fact they limit the "herd" of the ring particles as a shepherd. Due to their gravitational effect, they pick up particles and deflect them from their original orbits through orbital resonance. This causes gaps in the ring system, such as the particularly striking Cassini Division, as well as other characteristic bands, or strange "twisted" deformation of rings. Discovery The existence of shepherd moons was theorized in early 1979. Observations of the rings of Uranus show that they are very thin and well defined, with sharp gaps between rings. To explain this, Goldreich and Tremaine suggested that two small satellites that were undetected at the time might be confining each ring. The first images of shepherd satellites were taken later that year by Voyager 1. Examples Jupiter Sev ...
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Peter Goldreich
Peter Goldreich (born July 14, 1939) is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology. Since 2005 he has also been a professor at the Institute for Advanced Study in Princeton, New Jersey. Asteroid 3805 Goldreich is named after him. Career Goldreich received a bachelor of science in engineering physics from Cornell University in 1960, and obtained a Ph.D. from Cornell in 1963 under the supervision of Thomas Gold. In 1963 and 1964 Goldreich was a postdoctoral fellow at Cambridge University. From 1964 to 1966 he was an assistant professor of astronomy and geophysics at UCLA. Goldreich joined the faculty at Caltech in 1966 as an associate professor. He later became a full professor in 1969 while remaining at Caltech, and in 1981 he became the Lee A. DuBridge Professor of Astrophysics & ...
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Prometheus Und Pandora
In Greek mythology, Prometheus (; , , possibly meaning "forethought")Smith"Prometheus". is a Titan god of fire. Prometheus is best known for defying the gods by stealing fire from them and giving it to humanity in the form of technology, knowledge, and more generally, civilization. In some versions of the myth, he is also credited with the creation of humanity from clay. Prometheus is known for his intelligence and for being a champion of humankind, and is also generally seen as the author of the human arts and sciences. He is sometimes presented as the father of Deucalion, the hero of the flood story. The punishment of Prometheus as a consequence of the theft of fire and giving it to humans is a popular subject of both ancient and modern culture. Zeus, king of the Olympian gods, sentenced Prometheus to eternal torment for his transgression. Prometheus was bound to a rock, and an eagle—the emblem of Zeus—was sent to eat his liver (in ancient Greece, the liver was though ...
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Association For Computing Machinery
The Association for Computing Machinery (ACM) is a US-based international learned society for computing. It was founded in 1947 and is the world's largest scientific and educational computing society. The ACM is a non-profit professional membership group, claiming nearly 110,000 student and professional members . Its headquarters are in New York City. The ACM is an umbrella organization for academic and scholarly interests in computer science ( informatics). Its motto is "Advancing Computing as a Science & Profession". History In 1947, a notice was sent to various people: On January 10, 1947, at the Symposium on Large-Scale Digital Calculating Machinery at the Harvard computation Laboratory, Professor Samuel H. Caldwell of Massachusetts Institute of Technology spoke of the need for an association of those interested in computing machinery, and of the need for communication between them. ..After making some inquiries during May and June, we believe there is ample interest to ...
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SIGCHI
The Special Interest Group on Computer–Human Interaction (SIGCHI) is one of the Association for Computing Machinery's special interest groups which is focused on human–computer interactions (HCI). It hosts the flagship annual international HCI conference, CHI, with over 3,000 attendees, and publishes ''ACM Interactions'' and ''ACM Transactions on Computer-Human Interaction'' (TOCHI). It also sponsors over 20 specialized conferences and provides in-cooperation support to over 30 conferences. SIGCHI has two membership publications, the ACM TechNews - SIGCHI Edition and ''ACM Interactions''. Until 2000, the '' SIGCHI Bulletin'' was also published as a membership publication. History SIGCHI was formed in 1982 by renaming and refocusing the Special Interest Group on Social and Behavioral Computing (SIGSOC). Lorraine Borman, previously editor of the '' SIGSOC Bulletin'', was its first chair. The formation of the ACM SIGCHI was first publicly announced in 1982 during the ''Human ...
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