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Lunar Laser Ranging Experiment
Lunar Laser Ranging (LLR) is the practice of measuring Lunar distance (astronomy), the distance between the surfaces of the Earth and the Moon using Lidar, laser ranging. The distance can be calculated from the Round-trip delay, round-trip time of laser light pulses travelling at the speed of light, which are reflected back to Earth by the Moon's surface or by List of retroreflectors on the Moon, one of several retroreflectors installed on the Moon. Three were placed by the United States' Apollo program (Apollo 11, 11, Apollo 14, 14, and Apollo 15, 15), two by the Soviet Lunokhod programme, Lunokhod 1 and 2 missions, and one by India's Chandrayaan-3 mission. Although it is possible to reflect light or radio waves directly from the Moon's surface (a process known as Earth–Moon–Earth communication, EME), a much more precise range measurement can be made using retroreflectors, since because of their small size, the temporal spread in the reflected signal is much smaller and beca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollo 11 Lunar Laser Ranging Experiment
Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, music and dance, truth and prophecy, healing and diseases, the Sun and light, poetry, and more. One of the most important and complex of the Greek gods, he is the son of Zeus and Leto, and the twin brother of Artemis, goddess of the hunt. He is considered to be the most beautiful god and is represented as the ideal of the ''kouros'' (ephebe, or a beardless, athletic youth). Apollo is known in Greek-influenced Etruscan mythology as ''Apulu''. As the patron deity of Delphi (''Apollo Pythios''), Apollo is an oracular god—the prophetic deity of the Pythia, Delphic Oracle and also the deity of ritual purification. His oracles were often consulted for guidance in various matters. He was in general seen as the god who affords help and wards off e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Guardian
''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardian'' is part of the Guardian Media Group, owned by the Scott Trust Limited. The trust was created in 1936 to "secure the financial and editorial independence of ''The Guardian'' in perpetuity and to safeguard the journalistic freedom and liberal values of ''The Guardian'' free from commercial or political interference". The trust was converted into a limited company in 2008, with a constitution written so as to maintain for ''The Guardian'' the same protections as were built into the structure of the Scott Trust by its creators. Profits are reinvested in its journalism rather than distributed to owners or shareholders. It is considered a newspaper of record in the UK. The editor-in-chief Katharine Viner succeeded Alan Rusbridger in 2015. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'' is the peer review, peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' cover the full range of List of academ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruby Laser
A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. The first working laser was a ruby laser made by Theodore H. "Ted" Maiman at Hughes Research Laboratories on May 16, 1960. Ruby lasers produce pulses of coherent visible light at a wavelength of 694.3 nm, which is a deep red color. Typical ruby laser pulse lengths are on the order of a millisecond. Design A ruby laser most often consists of a ruby rod that must be pumped with very high energy, usually from a flashtube, to achieve a population inversion. The rod is often placed between two mirrors, forming an optical cavity, which oscillate the light produced by the ruby's fluorescence, causing stimulated emission. Ruby is one of the few solid state lasers that produce light in the visible range of the spectrum, lasing at 694.3 nanometers, in a deep red color, with a very narrow linewidth of 0.53 nm.''Principles of Lasers'' By Orazio Svelto – Plenum Press 1976 Page 367–370 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q-switching
Q-switching, sometimes known as giant pulse formation or Q-spoiling, is a technique by which a laser can be made to produce a pulsed output beam. The technique allows the production of light pulses with extremely high (gigawatt) peak power, much higher than would be produced by the same laser if it were operating in a continuous wave (constant output) mode. Compared to mode locking, another technique for pulse generation with lasers, Q-switching leads to much lower pulse repetition rates, much higher pulse energies, and much longer pulse durations. The two techniques are sometimes applied together. Q-switching was first proposed in 1958 by Gordon Gould, p. 93. and independently discovered and demonstrated in 1961 or 1962 by R.W. Hellwarth and F.J. McClung at Hughes Research Laboratories using electrically switched Kerr cell shutters in a ruby laser. Optical nonlinearities such as Q-switching were fully explained by Nicolaas Bloembergen, who won the Nobel Prize in 1981 for this w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crimean Astrophysical Observatory
The Crimean Astrophysical Observatory (CrAO, obs. code: 095) is located at Nauchnij research campus, near the Central Crimean city of Bakhchysarai, on the Crimean peninsula. CrAO is often called simply by its location and campus name, Crimea–Nauchnij, still ranks among the worldwide most prolific discovery sites for minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...s. CrAO has also been publishing the ''Bulletin of the Crimean Astrophysical Observatory'' since 1947, in English since 1977. The observatory facilities ( IAU code 095) are located on territory of settlement of Nauchnyi since the mid-1950s; before that, they were further south, near Simeiz. The latter facilities still see some use, and are referred to as the Crimean Astrophysical Observator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giorgio Fiocco
Giorgio Fiocco (13 June 1931 – 31 July 2012) was an Italian physicist, known for the development of the Lidar for the remote sensing of the atmosphere. In 1962 at MIT, together with Louis Smullin, Fiocco developed the first Lidar system, aiming a laser beam to the Moon and detecting the return pulse. Fiocco was full professor of geophysics at the University of Florence, then since 1974, professor of Terrestrial Physics at the Sapienza University of Rome The Sapienza University of Rome (), formally the Università degli Studi di Roma "La Sapienza", abbreviated simply as Sapienza ('Wisdom'), is a Public university, public research university located in Rome, Italy. It was founded in 1303 and is .... From 1994 to 1995 Fiocco was president of the Italian Space Agency. Fiocco pioneered the application of the Lidar to the remote sensing of the atmosphere. He died in Rome on 31 July 2012. Publications * * * References * * 1931 births 2012 deaths Italian p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Smullin
Louis Dijour Smullin (February 5, 1916 – June 4, 2009) was an American electrical engineer who spend most of his career at the Massachusetts Institute of Technology (MIT). He is best known for his work with Giorgio Fiocco to measure the distance to the Moon using a ruby laser in 1962, shortly after that device was invented. Earlier, he had worked in the microwave radar field at the MIT Radiation Laboratory and was instrumental in creating the Lincoln Laboratory that carried on this work. Later he worked on developing instrumentation for nuclear fusion research and many other projects. He retired in 1986 but worked in the department until 2001. Life and career Smullin was born in Detroit to Isaac M. Smullin and Ida May. His parents were Russian Jewish immigrants. His father was an advocate for the Communist International Labor Defense, was involved with Th. L. Poindexter in Detroit around 1938 in the Roumanian Workers Educational Association of America, and later established ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Ranging Retroreflector Apollo 15
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow and the optical amplifier patented by Gordon Gould. A laser differs from other sources of light in that it emits light that is coherence (physics), ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling uses such as optical communication, laser cutting, and Photolithography#Light sources, lithography. It also allows a laser beam to stay narrow over great distances (collimated light, collimation), used in laser pointers, lidar, and free-space optical communication. Lasers can also have high temporal coherence, which permits them to emit light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALSEP AS15-85-11468
The Apollo Lunar Surface Experiments Package (ALSEP) comprised a set of scientific instruments placed by the astronauts at the landing site of each of the five Apollo program, Apollo missions to land on the Moon following Apollo 11 (Apollos Apollo 12, 12, Apollo 14, 14, Apollo 15, 15, Apollo 16, 16, and Apollo 17, 17). Apollo 11 left a smaller package called the Early Apollo Scientific Experiments Package, or EASEP. Background The instrumentation and experiments that would comprise ALSEP were decided in February 1966. Specifically, the experiments, institutions responsible, and principal investigators and coinvestigators were: * Passive Lunar Seismic Experiment: Massachusetts Institute of Technology, Frank Press; Columbia University, George Sutton; Georgia Tech, Robert Hostetler * Lunar Surface Magnetometer: Ames Research Center, C. P. Sonett; Marshall Space Flight Center, Jerry Modisette. * Medium-Energy Solar Wind Spectrometer, Solar Wind: Jet Propulsion Laboratory, C. W. Snyd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
