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Borealis Basin
The North Polar Basin, more commonly known as the Borealis Basin, is a large basin in the northern hemisphere of Mars that covers 40% of the planet. Some scientists have postulated that the basin formed during the impact of a single, large body roughly 2% of the mass of Mars, having a diameter of about 1,900 km (1,200 miles) early in the history of Mars, around 4.5 billion years ago. However, the basin is not currently recognized as an impact basin by the IAU. The basin is one of the flattest areas in the Solar System, and has an elliptical shape. Large regions within the Borealis Basin Because the Borealis basin covers 40% of the surface of Mars, and much of the Northern Hemisphere, many currently recognized regions of Mars lie within it: * Acidalia Planitia * Arcadia Planitia * Planum Boreum * Utopia Planitia * Vastitas Borealis Borealis Impact Formation of the Borealis Basin One possible explanation for the basin's low, flat and relatively crater-free topogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Topography (MOLA Dataset) With Poles HiRes
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of Mars surface color, its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () Atmosphere of Mars, atmosphere. At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from and cosmic radiation is high. Mars retains some water, Groundwater on Mars, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and Martian polar ice caps, ice caps (with seasonal snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half List of Solar System objects by size, as wide as Earth or twice the Moon, with a diameter of , and has a surface area the size of all the dry land of Earth. Martian regolith#Atmospheric dust, Fine dust is prevalent across the surface and the atmosphere, bein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Largest Impact Crater In The Solar System
Following are the largest impact craters on various worlds of the Solar System. For a full list of named craters, ''see List of craters in the Solar System''. The ratio column compares the crater diameter with the diameter of the impacted celestial body. The maximum crater diameter is 157% of the body diameter (the circumference along a great circle). See also * List of Solar System extremes ** List of largest lakes and seas in the Solar System ** List of largest rifts and valleys in the Solar System ** List of tallest mountains in the Solar System References {{Solar System table Lists of impact craters, * Solar System Lists of superlatives in astronomy, Craters, largest in the Solar System Solar System-related lists, Craters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion (astrophysics)
In astrophysics, accretion is the accumulation of particles into a massive object by gravity, gravitationally attracting more matter, typically gaseous matter, into an accretion disk. Most astronomical objects, such as galaxy, galaxies, stars, and planets, are formed by accretion processes. Overview The accretion model that Earth and the other terrestrial planets formed from meteoric material was proposed in 1944 by Otto Schmidt, followed by the ''protoplanet theory'' of William McCrea (astronomer), William McCrea (1960) and finally the ''capture theory'' of Michael Woolfson. For details of Kant's position, see In 1978, Andrew Prentice resurrected the initial Laplacian ideas about planet formation and developed the ''modern Laplacian theory''. None of these models proved completely successful, and many of the proposed theories were descriptive. The 1944 accretion model by Otto Schmidt was further developed in a quantitative way in 1969 by Viktor Safronov. He calculated, in deta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy. Earth's lithosphere Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the lithospheric mantle (or mantle lithosphere), the uppermost part of the mantle that is not convecting. The layer below the lithosphere is called the asthenosphere, which is the weaker, hotter, and deeper part of the upper mantle that is able to convect. The lithosphere–asthenosphere boundary is defined by a difference in response to stress. The lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle f ... [...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] |
Phobos (moon)
Phobos (; astronomical naming conventions, systematic designation: ) is the innermost and larger of the two moons of Mars, natural satellites of Mars, the other being Deimos (moon), Deimos. The two moons were discovered in 1877 by American astronomer Asaph Hall. Phobos is named after Phobos (mythology), the Greek god of fear and panic, who is the son of Ares (Mars) and twin brother of Deimos (deity), Deimos. Phobos is a small, irregularly shaped object with a mean radius of . It orbits from the Martian surface, closer to its Primary (astronomy), primary body than any other known natural satellite to a planet. It orbits Mars much faster than Mars rotates and completes an orbit in just 7 hours and 39 minutes. As a result, from the surface of Mars it appears to rise in the west, move across the sky in 4 hours and 15 minutes or less, and set in the east, twice each Mars sol, Martian day. Phobos is one of the least reflective bodies in the Solar System, with an albedo of 0.071. Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moons Of Mars
The two natural satellite, moons of Mars (planet), Mars are Phobos (moon), Phobos and Deimos (moon), Deimos. They are irregular in shape. Both were discovered by American astronomer Asaph Hall in August 1877 and are named after the Greek mythology, Greek mythological twin characters Phobos (mythology), Phobos (fear and panic) and Deimos (deity), Deimos (terror and dread) who accompanied their father Ares (Mars (mythology), Mars in Roman mythology, hence the name of the planet) into battle. Compared to the Earth's Moon, the moons Phobos and Deimos are very small. Phobos has a diameter of 22.2 km (13.8 mi) and a mass of 1.08 kg, while Deimos measures 12.6 km (7.8 mi) across, with a mass of 1.5 kg. Phobos orbits closer to Mars, with a semi-major axis of and an orbital period of 7.66 hours; while Deimos orbits farther with a semi-major axis of and an orbital period of 30.35 hours. Two major hypotheses have emerged as to the origin of the moons: The first sugges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phobos Deimos Diff Horizontal
Phobos (Greek for "fear") most commonly refers to: * Phobos (moon), a moon of Mars * Phobos (mythology), the Greek god and personification of fear and panic Phobos may also refer to: Fictional characters * Phobos (Marvel Comics), several characters from ''Marvel'' * Phobos (''W.I.T.C.H.''), a character from ''W.I.T.C.H.'' * Huitzil or Phobos, a character in the ''Darkstalkers'' game series * Phobos (Sailor Moon), a character from ''Sailor Moon''. Computer programming * Project Phobos, a Java-based web application environment * A runtime and standard library of D programming language Transportation and vehicles * Phobos program The Phobos program () was an uncrewed space mission consisting of two probes launched by the Soviet Union to study Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appeara ..., a Soviet space program of the late 1980s * USS ''Phobos'' (AK-129), a World War II U.S. Navy ''Cra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convection
Convection is single or Multiphase flow, multiphase fluid flow that occurs Spontaneous process, spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow. Convective flow may be Transient state, transient (such as when a Multiphasic liquid, multiphase mixture of oil and water separates) or steady state (see convection cell). The convection may be due to Gravity, gravitational, Electromagnetism, electromagnetic or Fictitious force, fictitious body forces. Convection (heat transfer), Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its Earth's mantle, mantle. Discrete convective cells in the atmosphere can be identified by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle (geology)
A mantle is a layer inside a planetary body bounded below by a Planetary core, core and above by a Crust (geology), crust. Mantles are made of Rock (geology), rock or Volatile (astrogeology), ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone planetary differentiation, differentiation by density. All Terrestrial planet, terrestrial planets (including Earth), half of the giant planets, specifically ice giants, a number of Asteroid, asteroids, and some planetary Natural satellite, moons have mantles. Examples Earth The Earth's mantle is a layer of Silicate minerals, silicate rock between the Crust (geology), crust and the Earth's outer core, outer core. Its mass of 4.01 × 1024 kg is 67% the mass of the Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly solid, but in Geologic time scale, geological time it behaves as a Viscosity, visc ... [...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] |
