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Stickney Crater
Stickney is the largest crater on Phobos, which is a satellite of Mars. It is in diameter, taking up a substantial proportion of the moon's surface. Naming The crater is named after mathematician Chloe Angeline Stickney Hall, the wife of Phobos's discoverer Asaph Hall, whose support was credited by her husband as critical for his discovery of the moon. The crater was named in 1973, based on ''Mariner 9'' images, by an IAU nomenclature committee chaired by Carl Sagan.. Formation There are two models for the age of Stickney, based on the differing possible dates at which Phobos began to orbit around Mars. If Phobos has been orbiting for 4.3 Ga (billion years) then Stickney formed 4.2 Ga ago, but if Phobos has only been orbiting for 3.5 Ga then it formed 2.6 Ga ago. The impact created a large amount of ejecta which escaped Phobos's gravity and entered into orbit around Mars for a period not exceeding 1000 years (some crashed back onto Phobos, and creating secondary impact crat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Crater
An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters are typically circular, though they can be elliptical in shape or even irregular due to events such as landslides. Impact craters range in size from microscopic craters seen on lunar rocks returned by the Apollo Program to simple bowl-shaped depressions and vast, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury (planet), Mercury, Callisto (moon), Callisto, Ganymede (moon), Ganymede, and most small moons and asteroids. On other planet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown University
Brown University is a Private university, private Ivy League research university in Providence, Rhode Island, United States. It is the List of colonial colleges, seventh-oldest institution of higher education in the US, founded in 1764 as the ''College in the English Colony of Rhode Island and Providence Plantations''. One of nine colonial colleges chartered before the American Revolution, it was the first US college to codify that admission and instruction of students was to be equal regardless of the religious affiliation of students. The university is home to the oldest applied mathematics program in the country and oldest engineering program in the Ivy League. It was one of the early doctoral-granting institutions in the U.S., adding masters and doctoral studies in 1887. In 1969, it adopted its Open Curriculum (Brown University), Open Curriculum after student lobbying, which eliminated mandatory Curriculum#Core curriculum, general education distribution requirements. In 197 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deimos (moon)
Deimos (; astronomical naming conventions#Natural satellites, systematic designation: Mars II) is the smaller and outer of the two moons of Mars, natural satellites of Mars, the other being Phobos (moon), Phobos. Deimos has a mean radius of and takes 30.3 hours to orbit Mars. Deimos is from Mars, much farther than Mars's other moon, Phobos. It is named after Deimos (deity), Deimos, the Greek mythology, Ancient Greek god and personification of dread and terror. Discovery and etymology Deimos was discovered by Asaph Hall at the United States Naval Observatory in Washington, D.C., on 12 August 1877, at about 07:48 Coordinated Universal Time, UTC. Hall, who also discovered Phobos (moon), Phobos shortly afterwards, had been specifically searching for Martian moons at the time. The moon is named after Deimos (deity), Deimos, a figure representing fear, dread in Greek mythology. The name was suggested by academic Henry George Madan, Henry Madan, who drew from Book XV of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a Public university, public Land-grant university, land-grant research university in Tucson, Arizona, United States. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university established in the Arizona Territory. The University of Arizona is one of three universities governed by the Arizona Board of Regents (the University of Arizona, Arizona State University, and Northern Arizona University). , the university enrolled 53,187 students in 22 separate colleges/schools, including the Eller College of Management, the Wyant College of Optical Sciences, the University of Arizona College of Medicine – Phoenix, College of Medicine – Phoenix, the University of Arizona College of Medicine – Tucson, College of Medicine – Tucson, and the James E. Rogers College of Law. The university is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by California Institute of Technology (Caltech) researchers, the laboratory is now owned and sponsored by NASA and administered and managed by Caltech. The primary function of the laboratory is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating the NASA Deep Space Network (DSN). Among the major active projects at the laboratory, some are the Mars 2020 mission, which includes the ''Perseverance (rover), Perseverance'' rover; the Mars Science Laboratory mission, including the ''Curiosity (rover), Curiosity'' rover; the ''Mars Reconnaissance Orbiter''; the ''Juno (spacecraft), Juno'' spacecraft orbiting Jupiter; the ''Soil Moisture Active P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Geophysical Union
The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, Atmospheric science, atmospheric, Oceanography, ocean, Hydrology, hydrologic, Astronomy, space, and Planetary science, planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences. The geophysical sciences involve four fundamental areas: atmospheric sciences, atmospheric and ocean sciences; solid-Earth sciences; hydrologic sciences; and space sciences. The organization's headquarters is located on Florida Avenue in Washington, D.C. History The AGU was established in December 1919 by the United States National Research Council, National Research Council (NRC) to represent the United States in the International Union of Geodesy and Geophysics (IUGG), and its first chairman w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geophysical Research Letters
''Geophysical Research Letters'' is a biweekly peer-reviewed scientific journal of geoscience published by the American Geophysical Union that was established in 1974. The editor-in-chief iKristopher Karnauskas Aims and scope The journal aims for rapid publication of concise research reports on one or more of the disciplines covered by the American Geophysical Union, such as atmospheric sciences, solid Earth, space science, oceanography, hydrology, land surface processes, and the cryosphere. The journal also publishes invited reviews that cover advances achieved during the past two or three years. The target readership is the earth science community, the broader scientific community, and the general public. Abstracting and indexing This journal is abstracted and indexed in: According to the 2020 ''Journal Citation Reports'', the journal has a 2019 impact factor of 4.58. ''Geophysical Research Letters'' was also the 5th most cited publication on climate change Pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porosity
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, petrophysics, hydrology, earth sciences, soil mechanics, rock mechanics, and engineering. Void fraction in two-phase flow In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universe Today
Universe Today (U.T.) is a North American-based non-commercial space and astronomy news website founded by Fraser Cain. The domain was registered on December 30, 1998, and the website went live in March 1999. ''Universe Today'' assumed its current form on July 24, 2003, featuring astronomy news and other space-related content. In early September 2005, the website’s forum section merged with '' Bad Astronomy'' to create a combined site with the BAUT forum. During April 2011, the Association of British Science Writers noted that ''Universe Today'' decided not to make preparations for reporting on embargoed stories until they are public knowledge. Emily Lakdawalla said that she relies on ''Universe Today'' and '' Bad Astronomy'' to "give ... an independent look at big news stories". Publications ''Universe Today'' has published two books, which are available both as e-books and on physical media: * * See also * '' Astronomy Cast'' * ''Space.com Space.com is an on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goddard Space Flight Center
The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately northeast of Washington, D.C., in Greenbelt, Maryland, United States. Established on May 1, 1959, as NASA's first space flight center, GSFC employs about 10,000 civil servants and contractors. Named for American rocket propulsion pioneer Robert H. Goddard, it is one of ten major NASA field centers. GSFC is partially within the former Goddard, Maryland, Goddard census-designated place; it has a Greenbelt, Maryland, Greenbelt mailing address.CENSUS 2000 BLOCK MAP: GODDARD CDP (PDF). U.S. Census Bureau. Retrieved September 1, 2018. 1990 Census map of Prince George's County [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tidal Forces
The tidal force or tide-generating force is the difference in gravitational attraction between different points in a gravitational field, causing bodies to be pulled unevenly and as a result are being stretched towards the attraction. It is the differential force of gravity, the net between gravitational forces, the derivative of gravitational potential, the gradient of gravitational fields. Therefore tidal forces are a residual force, a secondary effect of gravity, highlighting its spatial elements, making the closer near-side more attracted than the more distant far-side. This produces a range of tide, tidal phenomena, such as ocean tides. Earth's tides are mainly produced by the relative close gravitational field of the Moon and to a lesser extend by the stronger, but further away gravitational field of the Sun. The ocean on the side of Earth facing the Moon is being pulled by the gravity of the Moon away from Earth's crust, while on the other side of Earth there the crust is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
