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Lineated Valley Fill
Lineated valley fill (LVF), also called lineated floor deposit, is a feature of the floors of some channels on Mars, exhibiting ridges and grooves that seem to flow around obstacles. Shadow measurements show that at least some of the ridges are several metres high. LVF is believed to be ice-rich. Hundreds of metres of ice probably lie protected in LVF under a thin layer of debris. The debris consists of wind-borne dust, material from alcove walls, and lag material remaining after ice sublimated (changed from a solid directly to a gas) from a rock-ice mixture. Some glaciers on Earth show similar ridges. High-resolution pictures taken with HiRISE reveal that some of the surfaces of lineated valley fill are covered with strange patterns called closed-cell and open-cell brain terrain. The terrain resembles a human brain. It is believed to be caused by cracks in the surface accumulating dust and other debris, together with ice sublimating from some of the surfaces. The cracks are th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), 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 (moon), Phobos and Deimos (moon), Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and List of tallest mountains in the Solar System, highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The North Polar Basin (Mars), Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Orbiter Laser Altimeter
260px, MOLA topographic images of the two hemispheres of Mars. This image appeared on the cover of ''Science'' magazine in May 1999. The Mars Orbiter Laser Altimeter (MOLA) was one of five instruments on the ''Mars Global Surveyor'' (MGS) spacecraft, which operated in Mars orbit from September 1997 to November 2006. However, the MOLA instrument transmitted altimetry data only until June 2001. The MOLA instrument transmitted infrared laser pulses towards Mars at a rate of 10 times per second, and measured the time of flight to determine the range (distance) of the MGS spacecraft to the Martian surface. The range measurements resulted in precise topographic maps of Mars. The precision maps are applicable to studies in geophysics, geology and atmospheric circulation. MOLA also functioned as a passive radiometer, and measured the radiance of the surface of Mars at 1064 nanometers. Planetary laser altimetry A laser altimeter is an instrument that measures the distance from an orbiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water On Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of flowing sand and dust slipping downhill to make dark streaks.Recurring Martian Streaks: Flowing Sand, Not Water? Nasa.org 2017-11-20 The only place where water ice is visible at the surface is at the north polar ice cap. Abundant water ice is also present beneath the permanent |
Climate Of Mars
The climate of Mars has been a topic of scientific curiosity for centuries, in part because it is the only terrestrial planet whose surface can be directly observed in detail from the Earth with help from a telescope. Although Mars is smaller than the Earth, 11% of Earth's mass, and 50% farther from the Sun than the Earth, its climate has important similarities, such as the presence of polar ice caps, seasonal changes and observable weather patterns. It has attracted sustained study from planetologists and climatologists. While Mars' climate has similarities to Earth's, including periodic ice ages, there are also important differences, such as much lower thermal inertia. Mars' atmosphere has a scale height of approximately , 60% greater than that on Earth. The climate is of considerable relevance to the question of whether life is or ever has been present on the planet. The climate briefly received more interest in the news due to NASA measurements indicating increased sublima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fretted Terrain
Fretted terrain is a type of surface feature common to certain areas of Mars and was discovered in Mariner 9 images. It lies between two different types of terrain. The surface of Mars can be divided into two parts: low, young, uncratered plains that cover most of the northern hemisphere, and high-standing, old, heavily cratered areas that cover the southern and a small part of the northern hemisphere. Between these two zones is a region called the Martian dichotomy and parts of it contain fretted terrain. This terrain contains a complicated mix of cliffs, mesas, buttes, and straight-walled and sinuous canyons. It contains smooth, flat lowlands along with steep cliffs. The scarps or cliffs are usually 1 to 2 km high. Channels in the area have wide, flat floors and steep walls. Fretted terrain shows up in northern Arabia, between latitudes 30°N and 50°N and longitudes 270°W and 360°W, and in Aeolis Mensae, between 10 N and 10 S latitude and 240 W and 210 W longitude.I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deuteronilus Mensae
Deuteronilus Mensae is a region on Mars 937 km across and centered at . It covers 344°–325° West and 40°–48° North. Deuteronilus region lies just to the north of Arabia Terra and is included in the Ismenius Lacus quadrangle. It is along the dichotomy boundary, that is between the old, heavily cratered southern highlands and the low plains of the northern hemisphere. The region contains flat-topped knobby terrain that may have been formed by glaciers at some time in the past. Deuteronilus Mensae is to the immediate west of Protonilus Mensae and Ismeniae Fossae. Glaciers persist in the region in modern times, with at least one glacier estimated to have formed as recently as 100,000 to 10,000 years ago. Recent evidence from the radar on the Mars Reconnaissance Orbiter has shown that parts of Deuteronilus Mensae do indeed contain ice. Source of ice It is now widely believed that ice accumulated in many areas of Mars, including Deuteronilus Mensae, when the planet's orbi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protonilus Mensae
Protonilus Mensae is an area of Mars in the Ismenius Lacus quadrangle. It is centered on the coordinates of 43.86° N and 49.4° E. Its western and eastern longitudes are 37° E and 59.7° E. North and south latitudes are 47.06° N and 39.87° N. Protonilus Mensae is between Deuteronilus Mensae and Nilosyrtis Mensae; all lie along the Martian dichotomy boundary. Its name was adapted by the IAU in 1973. Mapdeuteronilus.jpg, Map showing the relation of Protonilus and Deuteronilus Mensae to other nearby regions. Colors refer to altitudes. The surface is described as fretted terrain. This terrain contains cliffs, mesas, and wide flat valleys. Surface features are believed to have been caused by debris-covered glaciers. These glaciers are termed lobate debris aprons (LDA) when surrounding mounds and mesas. When glaciers are in valleys, they are called Lineated valley fill (LVF). Parts of the surface show flow patterns that start in numerous alcoves located within the walls of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nilosyrtis Mensae
Nilosyrtis Mensae is an area of Mars in the Casius quadrangle. It is centered on the coordinates of 36.87° N and 67.9° E. Its western and eastern longitudes are 51.1° E and 74.4° E. North and south latitudes are 36.87° N and 29.61° N. Nilosyrtis Mensae is just to the east of Protonilus Mensae and both lie along the Martian dichotomy boundary. Its name was adapted by the IAU in 1973. It was named after a classical albedo feature, and it is across. The surface of Nilosyrtis Mensae is classified as fretted terrain. This terrain contains cliffs, mesas, and wide flat valleys. Surface features are believed to have been caused by debris-covered glaciers. These glaciers are termed lobate debris aprons when surrounding mounds and mesas. When the glaciers are in the valleys they are called lineated valley fill. Climate change caused ice-rich features For decades many features on Mars, including ones in Nilosyrtis Mensae, were believed to contain large amounts of ice. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martian Dichotomy
The most conspicuous feature of Mars is a sharp contrast, known as the Martian dichotomy, between the Southern and the Northern hemispheres. The two hemispheres' geography differ in elevation by 1 to 3 km. The average thickness of the Martian crust is 45 km, with 32 km in the northern lowlands region, and 58 km in the southern highlands. The boundary between the two regions is quite complex in places. One distinctive type of topography is called fretted terrain. It contains mesas, knobs, and flat-floored valleys having walls about a mile high. Around many of the mesas and knobs are lobate debris aprons that have been shown to be rock glaciers. Many large valleys formed by the lava erupted from the volcanoes of Mars cut through the dichotomy. The Martian dichotomy boundary includes the regions called Deuteronilus Mensae, Protonilus Mensae, and Nilosyrtis Mensae. All three regions have been studied extensively because they contain landforms believed to hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Planet
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar energy is rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazonian Period
The geological history of Mars follows the physical evolution of Mars as substantiated by observations, indirect and direct measurements, and various inference techniques. Methods dating back to 17th century techniques developed by Nicholas Steno, including the so-called law of superposition and stratigraphy, used to estimate the geological histories of Earth and the Moon, are being actively applied to the data available from several Martian observational and measurement resources. These include the landers, orbiting platforms, Earth-based observations, and Martian meteorites. Observations of the surfaces of many Solar System bodies reveal important clues about their evolution. For example, a lava flow that spreads out and fills a large impact crater is likely to be younger than the crater. On the other hand, a small crater on top of the same lava flow is likely to be younger than both the lava and the larger crater since it can be surmised to have been the product of a later, un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Tilt
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbital plane. It differs from orbital inclination. At an obliquity of 0 degrees, the two axes point in the same direction; that is, the rotational axis is perpendicular to the orbital plane. The rotational axis of Earth, for example, is the imaginary line that passes through both the North Pole and South Pole, whereas the Earth's orbital axis is the line perpendicular to the imaginary plane through which the Earth moves as it revolves around the Sun; the Earth's obliquity or axial tilt is the angle between these two lines. Earth's obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. Based on a continuously updated formula (here Laskar, 1986, though since 2006 the IMCCE and the IAU recommend the P03 model), Earth's mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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