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Crustal Magnetism
Crustal magnetism is the magnetic field of the crust of a planetary body. The crustal magnetism of Earth has been studied; in particular, various magnetic crustal anomalies have been studied. Two examples of crustal magnetic anomalies on Earth that have been studied in the Americas are the Brunswick magnetic anomaly (BMA) and East Coast magnetic anomaly (ECMA). Also, there can be a correlation between physical geological features and certain readings from crustal magnetism on Earth. Below the surface of the Earth, the crustal magnetism is lost because the temperature rises above the curie temperature of the materials producing the field. On Mars the crustal magnetic fields have been noted as affecting its ionosphere. (See also Atmosphere of Mars) The magnetic fields on Mars from its rocks and crust are thought to come from ferromagnetism and if the material is heated above its curie temperature the magnetic imprint is un-done. The Mars Global Surveyor (MGS) discovered magnetic stri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Crustal Magnetism MGS
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos and Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a large impact feature. Days and seasons on Mars are comparable to those of Earth, as the planets have a similar rotation period and tilt o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Mercury, Venus, Mars, Io, the Moon and other planetary bodies formed via igneous processes and were later modified by erosion, impact cratering, volcanism, and sedimentation. Most terrestrial planets have fairly uniform crusts. Earth, however, has two distinct types: continental crust and oceanic crust. These two types have different chemical compositions and physical properties and were formed by different geological processes. Types of crust Planetary geologists divide crust into three categories based on how and when it formed. Primary crust / primordial crust This is a planet's "original" crust. It forms from solidification of a magma ocean. Towa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere Of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and noble gases. The atmosphere of Mars is much thinner than Earth's. The average surface pressure is only about which is less than 1% of the Earth's value. The currently thin Martian atmosphere prohibits the existence of liquid water on the surface of Mars, but many studies suggest that the Martian atmosphere was much thicker in the past. The higher density during spring and fall is reduced by 25% during the winter when carbon dioxide partly freezes at the pole caps. The highest atmospheric density on Mars is equal to the density found above the Earth's surface and is ≈0.020 kg/m3. The atmosphere of Mars has been losing mass to space since the planet's core slowed down, and the leakage of gases still continues today. The atmosphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferromagnetism
Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials are the familiar metals noticeably attracted to a magnet, a consequence of their large magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an ''external'' magnetic field, and it is this temporarily induced magnetization inside a steel plate, for instance, which accounts for its attraction to the permanent magnet. Whether or not that steel plate acquires a permanent magnetization itself, depends not only on the strength of the applied field, but on the so-called coercivity of that material, which varies greatly among ferromagnetic materials. In physics, several different types of material magnetism are distinguished. Ferromagnetism (along with the similar effect ferrimagnetis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curie Temperature
In physics and materials science, the Curie temperature (''T''C), or Curie point, is the temperature above which certain materials lose their permanent magnetic properties, which can (in most cases) be replaced by induced magnetism. The Curie temperature is named after Pierre Curie, who showed that magnetism was lost at a critical temperature. The force of magnetism is determined by the magnetic moment, a dipole moment within an atom which originates from the angular momentum and spin of electrons. Materials have different structures of intrinsic magnetic moments that depend on temperature; the Curie temperature is the critical point at which a material's intrinsic magnetic moments change direction. Permanent magnetism is caused by the alignment of magnetic moments and induced magnetism is created when disordered magnetic moments are forced to align in an applied magnetic field. For example, the ordered magnetic moments (ferromagnetic, Figure 1) change and become disorder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Global Surveyor
''Mars Global Surveyor'' (MGS) was an American robotic space probe developed by NASA's Jet Propulsion Laboratory and launched November 1996. MGS was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed atmospheric monitoring for sister orbiters during aerobraking, and helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007. MGS remains in a stable near-polar circular orbit at about 450 km ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eridania Quadrangle
The Eridania quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Eridania quadrangle is also referred to as MC-29 (Mars Chart-29). The Eridania quadrangle lies between 30° and 65° south latitude and 180° and 240° west longitude on the planet Mars. Most of the classic region named Terra Cimmeria is found within this quadrangle. Part of the Electris deposits, a 100–200 meters thick, light-toned deposit covers the Eridania quadrangle. Many slopes in Eridania contain gullies, which are believed to be caused by flowing water. Martian Gullies The Eridania quadrangle is the location of gullies that may be due to recent flowing water. Gullies occur on steep slopes, especially on the walls of craters. Gullies are believed to be relatively young because they have few, if any craters. Moreover, they lie on top of sand dunes which themselves are considered to be quite young. Usually, ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terra Cimmeria
Terra Cimmeria is a large Martian region, centered at and covering at its broadest extent. It covers latitudes 15 N to 75 S and longitudes 170 to 260 W. It lies in the Eridania quadrangle. Terra Cimmeria is one part of the heavily cratered, southern highland region of the planet. The Spirit rover landed near the area. The word Cimmerium comes from an ancient Thracian seafaring people. The land was always covered in clouds and mist. A high altitude visual phenomena, probably a condensation cloud, was seen above this region in late March 2012. NASA tried to observe it with some of its Mars orbiters, including the THEMIS instrument on the 2001 Mars Odyssey spacecraft and MARCI on the Mars Reconnaissance Orbiter. Martian gullies Terra Cimmeria is the location of gullies that may be due to recent flowing water. Gullies occur on steep slopes, especially on the walls of craters. Gullies are believed to be relatively young because they have few if any craters. Moreover, they lie o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terra Sirenum
Terra Sirenum is a large region in the southern hemisphere of the planet Mars. It is centered at and covers 3900 km at its broadest extent. It covers latitudes 10 to 70 South and longitudes 110 to 180 W. Terra Sirenum is an upland area notable for massive cratering including the large Newton Crater. Terra Sirenum is in the Phaethontis quadrangle and the Memnonia quadrangle of Mars. A low area in Terra Sirenum is believed to have once held a lake that eventually drained through Ma'adim Vallis. Terra Sirenum is named after the Sirens, who were birds with the heads of girls. In the ''Odyssey'' these girls captured passing seamen and killed them. Chloride deposits Evidence of deposits of chloride based minerals in Terra Sirenum was discovered by the 2001 Mars Odyssey orbiter's Thermal Emission Imaging System in March 2008. The deposits are approximately 3.5 to 3.9 billion years old. This suggests that near-surface water was widespread in early Martian history, which ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, one that measures the direction of an ambient magnetic field, in this case, the Earth's magnetic field. Other magnetometers measure the magnetic dipole moment of a magnetic material such as a ferromagnet, for example by recording the effect of this magnetic dipole on the induced current in a coil. The first magnetometer capable of measuring the absolute magnetic intensity at a point in space was invented by Carl Friedrich Gauss in 1833 and notable developments in the 19th century included the Hall effect, which is still widely used. Magnetometers are widely used for measuring the Earth's magnetic field, in geophysical surveys, to detect magnetic anomalies of various types, and to determine the dipole moment of magnetic materials. In an air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plate Tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of ''continental drift'', an idea developed during the first decades of the 20th century. Plate tectonics came to be generally accepted by geoscientists after seafloor spreading was validated in the mid to late 1960s. Earth's lithosphere, which is the rigid outermost shell of the planet (the crust and upper mantle), is broken into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary: '' convergent'', '' divergent'', or ''transform''. Earthquakes, volcanic activity, mountain-building, and oceanic tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Prospector
''Lunar Prospector'' was the third mission selected by NASA for full development and construction as part of the Discovery Program. At a cost of $62.8 million, the 19-month mission was designed for a low polar orbit investigation of the Moon, including mapping of surface composition including Lunar hydrogen deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. The mission ended July 31, 1999, when the orbiter was deliberately crashed into a crater near the lunar south pole, after the presence of hydrogen was successfully detected. Data from the mission allowed the construction of a detailed map of the surface composition of the Moon, and helped to improve understanding of the origin, evolution, current state, and resources of the Moon. Several articles on the scientific results were published in the journal ''Science''. ''Lunar Prospector'' was managed by NASA Ames Research Center with the prime contractor Lockheed Martin. The Princip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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