Laser Ranging Retroreflector
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Laser Ranging Retroreflector
The Laser Ranging Retroreflector (LRRR) is the first ever deployable lunar laser ranging experiment. It was carried on Apollo 11 as part of the Early Apollo Scientific Experiments Package, and on Apollo 14 and Apollo 15 as part of the Apollo Lunar Surface Experiments Package (ALSEP). The LRRR consists of a series of corner reflectors set within a panel. Laser beams sent from Earth are bounced off the retroreflector and the timing of the return signal can be used to measure the distance from the signal source to the reflector. The reflector was conceived by James E. Faller in 1961. The experiment's principal investigator was initially Carroll Alley of the University of Maryland who was eventually succeeded by Faller. Background The motivation for a retroreflector came from a desire for a greater experimental basis for general relativity and specifically problems that arose with the Brans–Dicke theory of gravitation. A research group at Princeton University had been exploring ...
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Carroll Alley
Carroll Overton Alley, Jr. (June 13, 1927 – February 24, 2016) was an American physicist. He served as the Principal Investigator on the Apollo Program's Lunar Laser Ranging Experiment, which significantly restricted the possible range of spatial variation of the strength of the gravitational interaction. Alley was a PhD student of Robert Henry Dicke. Alley’s goal was to understand quantum mechanics, gravitation, and relativity. His lifelong research interests included experimental and theoretical questions about the foundations of gravitational and quantum physics. Alley developed some of the earliest important laboratory tests of Albert Einstein's theories of relativity. In recent years he became known for alternative theories of gravitation. He was a Physics professor at University of Maryland, College Park, emeritus since 2008, until his death on 24 February 2016. Career details Professor C. O. Alley served as the first chairman of the Lunar Ranging Experiment team. H ...
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Arthur D
Arthur is a masculine given name of uncertain etymology. Its popularity derives from it being the name of the legendary hero King Arthur. A common spelling variant used in many Slavic, Romance, and Germanic languages is Artur. In Spanish and Italian it is Arturo. Etymology The earliest attestation of the name Arthur is in the early 9th century Welsh-Latin text ''Historia Brittonum'', where it refers to a circa 5th century Romano-British general who fought against the invading Saxons, and who later gave rise to the famous King Arthur of medieval legend and literature. A possible earlier mention of the same man is to be found in the epic Welsh poem '' Y Gododdin'' by Aneirin, which some scholars assign to the late 6th century, though this is still a matter of debate and the poem only survives in a late 13th century manuscript entitled the Book of Aneirin. A 9th-century Breton landowner named Arthur witnessed several charters collected in the '' Cartulary of Redon''. The Irish bo ...
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Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar day) that is synchronized to its orbital period (Lunar month#Synodic month, lunar month) of 29.5 Earth days. This is the product of Earth's gravitation having tidal forces, tidally pulled on the Moon until one part of it stopped rotating away from the near side of the Moon, near side, making always the same lunar surface face Earth. Conversley, the gravitational pull of the Moon, on Earth, is the main driver of Earth's tides. In geophysical definition of planet, geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is , roughly one-quarter of Earth's (about as wide as the contiguous United States). Within the Solar System, it is the List of Solar System objects by ...
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Cosmic Ray
Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy, and from distant galaxies. Upon impact with Earth's atmosphere, cosmic rays produce showers of secondary particles, some of which reach the surface, although the bulk are deflected off into space by the magnetosphere or the heliosphere. Cosmic rays were discovered by Victor Hess in 1912 in balloon experiments, for which he was awarded the 1936 Nobel Prize in Physics. Direct measurement of cosmic rays, especially at lower energies, has been possible since the launch of the first satellites in the late 1950s. Particle detectors similar to those used in nuclear and high-energy physics are used on satellites and space probes for research into cosmic rays. Data from the Fermi Space Telescope (2013) have ...
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Laser Ranging Retroreflector
The Laser Ranging Retroreflector (LRRR) is the first ever deployable lunar laser ranging experiment. It was carried on Apollo 11 as part of the Early Apollo Scientific Experiments Package, and on Apollo 14 and Apollo 15 as part of the Apollo Lunar Surface Experiments Package (ALSEP). The LRRR consists of a series of corner reflectors set within a panel. Laser beams sent from Earth are bounced off the retroreflector and the timing of the return signal can be used to measure the distance from the signal source to the reflector. The reflector was conceived by James E. Faller in 1961. The experiment's principal investigator was initially Carroll Alley of the University of Maryland who was eventually succeeded by Faller. Background The motivation for a retroreflector came from a desire for a greater experimental basis for general relativity and specifically problems that arose with the Brans–Dicke theory of gravitation. A research group at Princeton University had been exploring ...
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Gordon J
Gordon may refer to: People * Gordon (given name), a masculine given name, including list of persons and fictional characters * Gordon (surname), the surname * Gordon (slave), escaped to a Union Army camp during the U.S. Civil War * Gordon Heuckeroth (born 1968), Dutch performer and radio and television personality, known professionally by the mononym Gordon * Clan Gordon, a Scottish clan Education * Gordon State College, a public college in Barnesville, Georgia * Gordon College (Massachusetts), a Christian college in Wenham, Massachusetts * Gordon College (Pakistan), a Christian college in Rawalpindi, Pakistan * Gordon College (Philippines), a public university in Subic, Zambales * Gordon College of Education, a public college in Haifa, Israel Places Australia * Gordon, Australian Capital Territory * Gordon, New South Wales * Gordon, South Australia * Gordon, Victoria * Gordon River, Tasmania * Gordon River (Western Australia) Canada * Gordon Parish, New Brunswick * ...
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William M
William is a masculine given name of Germanic origin. It became popular in England after the Norman conquest in 1066,All Things William"Meaning & Origin of the Name"/ref> and remained so throughout the Middle Ages and into the modern era. It is sometimes abbreviated "Wm." Shortened familiar versions in English include Will or Wil, Wills, Willy, Willie, Bill, Billie, and Billy. A common Irish form is Liam. Scottish diminutives include Wull, Willie or Wullie (as in Oor Wullie). Female forms include Willa, Willemina, Wilma and Wilhelmina. Etymology William is related to the German given name ''Wilhelm''. Both ultimately descend from Proto-Germanic ''*Wiljahelmaz'', with a direct cognate also in the Old Norse name ''Vilhjalmr'' and a West Germanic borrowing into Medieval Latin ''Willelmus''. The Proto-Germanic name is a compound of *''wiljô'' "will, wish, desire" and *''helmaz'' "helm, helmet".Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxfor ...
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David Todd Wilkinson
David Todd Wilkinson (May 13, 1935 – September 5, 2002) was an American cosmologist, specializing in the study of the cosmic microwave background radiation ( CMB). Education Wilkinson was born in Hillsdale, Michigan on May 13, 1935, and earned his Ph.D. in physics at the University of Michigan under the supervision of H. Richard Crane. Research and career Wilkinson was a Professor of Physics at Princeton University from 1965 until his retirement in 2002. He made fundamental contributions to many major cosmic microwave background experiments, including two NASA satellites: the Cosmic Background Explorer ( COBE) and the Wilkinson Microwave Anisotropy Probe ( WMAP), the latter of which was named in his honor after his death due to cancer on September 5, 2002. Accolades * Princeton President's Award for Distinguished Teaching * Election to the National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental org ...
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Robert H
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of ''Hrōþ, Hruod'' () "fame, glory, honour, praise, renown, godlike" and ''berht'' "bright, light, shining"). It is the second most frequently used given name of ancient Germanic origin.Reaney & Wilson, 1997. ''Dictionary of English Surnames''. Oxford University Press. It is also in use Robert (surname), as a surname. Another commonly used form of the name is Rupert (name), Rupert. After becoming widely used in Continental Europe, the name entered England in its Old French form ''Robert'', where an Old English cognate form (''Hrēodbēorht'', ''Hrodberht'', ''Hrēodbēorð'', ''Hrœdbœrð'', ''Hrœdberð'', ''Hrōðberχtŕ'') had existed before the Norman Conquest. The feminine version is Roberta (given name), Roberta. The Italian, Portuguese, and Spanish form is Roberto (given name), ...
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American Physical Society
The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of knowledge of physics. It publishes more than a dozen scientific journals, including the prestigious '' Physical Review'' and ''Physical Review Letters'', and organizes more than twenty science meetings each year. It is a member society of the American Institute of Physics. Since January 2021, it is led by chief executive officer Jonathan Bagger. History The American Physical Society was founded on May 20, 1899, when thirty-six physicists gathered at Columbia University for that purpose. They proclaimed the mission of the new Society to be "to advance and diffuse the knowledge of physics", and in one way or another the APS has been at that task ever since. In the early years, virtually the sole activity of the APS was to hold scientific m ...
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Scattering
In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiation) in the medium through which they pass. In conventional use, this also includes deviation of reflected radiation from the angle predicted by the law of reflection. Reflections of radiation that undergo scattering are often called ''diffuse reflections'' and unscattered reflections are called ''specular'' (mirror-like) reflections. Originally, the term was confined to light scattering (going back at least as far as Isaac Newton in the 17th century). As more "ray"-like phenomena were discovered, the idea of scattering was extended to them, so that William Herschel could refer to the scattering of "heat rays" (not then recognized as electromagnetic in nature) in 1800. John Tyndall, a pioneer in light scattering research, noted the connecti ...
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Massachusetts Institute Of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of modern technology and science. In response to the increasing Technological and industrial history of the United States, industrialization of the United States, William Barton Rogers organized a school in Boston to create "useful knowledge." Initially funded by a land-grant universities, federal land grant, the institute adopted a Polytechnic, polytechnic model that stressed laboratory instruction in applied science and engineering. MIT moved from Boston to Cambridge in 1916 and grew rapidly through collaboration with private industry, military branches, and new federal basic research agencies, the formation of which was influenced by MIT faculty like Vannevar Bush. In the late twentieth century, MIT became a leading center for research in compu ...
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