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Hafele–Keating Experiment
The Hafele–Keating experiment was a test of the theory of relativity. In 1971, Joseph C. Hafele, a physicist, and Richard E. Keating, an astronomer, took four cesium-beam atomic clocks aboard commercial airliners. They flew twice around the world, first eastward, then westward, and compared the clocks against others that remained at the United States Naval Observatory. When reunited, the three sets of clocks were found to disagree with one another, and their differences were consistent with the predictions of special and general relativity. Overview Kinematic time dilation According to special relativity, the rate of a clock is greatest according to an observer who is at rest with respect to the clock. In a frame of reference in which the clock is not at rest, the clock runs more slowly, as expressed by the Lorentz factor. This effect, called time dilation, has been confirmed in many tests of special relativity, such as the Ives–Stilwell experiment and others. Considering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hafele–Keating Experiment
The Hafele–Keating experiment was a test of the theory of relativity. In 1971, Joseph C. Hafele, a physicist, and Richard E. Keating, an astronomer, took four cesium-beam atomic clocks aboard commercial airliners. They flew twice around the world, first eastward, then westward, and compared the clocks against others that remained at the United States Naval Observatory. When reunited, the three sets of clocks were found to disagree with one another, and their differences were consistent with the predictions of special and general relativity. Overview Kinematic time dilation According to special relativity, the rate of a clock is greatest according to an observer who is at rest with respect to the clock. In a frame of reference in which the clock is not at rest, the clock runs more slowly, as expressed by the Lorentz factor. This effect, called time dilation, has been confirmed in many tests of special relativity, such as the Ives–Stilwell experiment and others. Considering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Probe A
Gravity Probe A (GP-A) was a space-based experiment to test the equivalence principle, a feature of Einstein's theory of relativity. It was performed jointly by the Smithsonian Astrophysical Observatory and the National Aeronautics and Space Administration. The experiment sent a hydrogen masera highly accurate frequency standardinto space to measure with high precision the rate at which time passes in a weaker gravitational field. Masses cause distortions in spacetime, which leads to the effects of length contraction and time dilation, both predicted results of Albert Einstein's theory of general relativity. Because of the bending of spacetime, an observer on Earth (in a lower gravitational potential) should measure a slower rate at which time passes than an observer that is higher in altitude (at higher gravitational potential). This effect is known as gravitational time dilation. The experiment was a test of a major consequence of Einstein's general relativity, the equivale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington, D
Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. * George Washington (1732–1799), the first president of the United States Washington may also refer to: Places England * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough ** Washington Old Hall, ancestral home of the family of George Washington * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catarman, Northern Samar *Washington, a barangay in Escalante, Negros Occidental *Washington, a barangay in San Jacinto, Masbate *Washington, a barangay in Surigao City United States * Washington, Wisconsin (other) * Fort Washington (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as '' Londinium'' and retains its medieval boundaries.See also: Independent city § National capitals The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. Since the 19th century, the name "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely comprises Greater London, governed by the Greater London Authority.The Greater London Authority consists of the Mayor of London and the London Assembly. The London Mayor is distinguished fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Physical Laboratory (United Kingdom)
The National Physical Laboratory (NPL) is the national measurement standards laboratory of the United Kingdom. It is one of the most extensive government laboratories in the UK and has a prestigious reputation for its role in setting and maintaining physical standards for British industry. Founded in 1900, it is one of the oldest metrology institutes in the world. Research and development work at NPL has contributed to the advancement of many disciplines of science, including the development early computers in the late 1940s and 1950s, construction of the first accurate atomic clock in 1955, and the invention and pioneering implementation of packet switching in the 1960s, which is today one of the fundamental technologies of the Internet. The former heads of NPL include many individuals who were pillars of the British scientific establishment. NPL is based at Bushy Park in Teddington, west London. It is under the management of the Department for Business, Energy and Industrial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turboprop
A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine stages, generating power at the point of exhaust. Some of the power generated by the turbine is used to drive the compressor and electric generator. The gases are then exhausted from the turbine. In contrast to a turbojet or turbofan, the engine's exhaust gases do not provide enough energy to create significant thrust, since almost all of the engine's power is used to drive the propeller. Technological aspects Exhaust thrust in a turboprop is sacrificed in favor of shaft power, which is obtained by extracting additional power (beyond that necessary to drive the compressor) from turbine ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Maryland
The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland. Founded in 1856, UMD is the flagship institution of the University System of Maryland. It is also the largest university in both the state and the Washington metropolitan area, with more than 41,000 students representing all fifty states and 123 countries, and a global alumni network of over 388,000. Together, its 12 schools and colleges offer over 200 degree-granting programs, including 92 undergraduate majors, 107 master's programs, and 83 doctoral programs. UMD is a member of the Association of American Universities and competes in intercollegiate athletics as a member of the Big Ten Conference. The University of Maryland's proximity to the nation's capital has resulted in many research partnerships with the federal government; faculty receive research funding and institutional support from many agencies, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Naval Research
The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to plan, foster, and encourage scientific research to maintain future naval power and preserve national security. It carries this out through funding and collaboration with schools, universities, government laboratories, nonprofit organizations, and for-profit organizations, and overseeing the Naval Research Laboratory, the corporate research laboratory for the Navy and Marine Corps. NRL conducts a broad program of scientific research, technology and advanced development. ONR Headquarters is in the Ballston neighborhood of Arlington, Virginia. ONR Global has offices overseas in Santiago, Sao Paulo, London, Prague, Singapore, and Tokyo. Overview ONR was authorized by an Act of Congress, Public Law 588, and subsequently approved by President ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington University In St
Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. * George Washington George Washington (February 22, 1732, 1799) was an American military officer, statesman, and Founding Father who served as the first president of the United States from 1789 to 1797. Appointed by the Continental Congress as commander of th ... (1732–1799), the first president of the United States Washington may also refer to: Places England * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough ** Washington Old Hall, ancestral home of the family of George Washington * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equipotential
In mathematics and physics, an equipotential or isopotential refers to a region in space where every point is at the same potential. This usually refers to a scalar potential (in that case it is a level set of the potential), although it can also be applied to vector potentials. An equipotential of a scalar potential function in -dimensional space is typically an ()-dimensional space. The del operator illustrates the relationship between a vector field and its associated scalar potential field. An equipotential region might be referred as being 'of equipotential' or simply be called 'an equipotential'. An equipotential region of a scalar potential in three-dimensional space is often an equipotential surface (or ''potential isosurface''), but it can also be a three-dimensional mathematical solid in space. The gradient of the scalar potential (and hence also its opposite, as in the case of a vector field with an associated potential field) is everywhere perpendicular to the equip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are the two pillars of modern physics. His mass–energy equivalence formula , which arises from relativity theory, has been dubbed "the world's most famous equation". His work is also known for its influence on the philosophy of science. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory. His intellectual achievements and originality resulted in "Einstein" becoming synonymous with "genius". In 1905, a year sometimes described as his ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annalen Der Physik
''Annalen der Physik'' (English: ''Annals of Physics'') is one of the oldest scientific journals on physics; it has been published since 1799. The journal publishes original, peer-reviewed papers on experimental, theoretical, applied, and mathematical physics and related areas. The editor-in-chief is Stefan Hildebrandt. Prior to 2008, its ISO 4 abbreviation was ''Ann. Phys. (Leipzig)'', after 2008 it became ''Ann. Phys. (Berl.)''. The journal is the successor to , published from 1790 until 1794, and ', published from 1795 until 1797. The journal has been published under a variety of names (', ', ', ''Wiedemann's Annalen der Physik und Chemie'') during its history. History Originally, was published in German, then a leading scientific language. From the 1950s to the 1980s, the journal published in both German and English. Initially, only foreign authors contributed articles in English but from the 1970s German-speaking authors increasingly wrote in English in order to reach an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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