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Nili Patera Dune Field
Nili Patera is a dune field on Mars. It is located on top of a lava bed, at the site of an ancient volcano, the Nili Patera caldera of Syrtis Major, near the Martian equator, and it is one of the most active dune fields of Mars. Its location coordinates on Mars are 8.7° N latitude, 67.3° E longitude. It is being actively studied by the HiRISE camera, on board the Mars Reconnaissance Orbiter, at the rate of one image every six weeks. The study of the movement of the dunes provides information regarding wind variation as a function of time and furthers the study of surface erosion characteristics of the Martian landscape. This information can then be used for the development and design of future Mars expeditions. The dunes of the Patera field are of the barchan type and their study by HiRISE was the first one to establish dune and ripple movement of a minimum of on Mars. The Patera dune field, was also the first to be investigated using the COSI-Corr software, which was origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nili Patera Dune Field
Nili Patera is a dune field on Mars. It is located on top of a lava bed, at the site of an ancient volcano, the Nili Patera caldera of Syrtis Major, near the Martian equator, and it is one of the most active dune fields of Mars. Its location coordinates on Mars are 8.7° N latitude, 67.3° E longitude. It is being actively studied by the HiRISE camera, on board the Mars Reconnaissance Orbiter, at the rate of one image every six weeks. The study of the movement of the dunes provides information regarding wind variation as a function of time and furthers the study of surface erosion characteristics of the Martian landscape. This information can then be used for the development and design of future Mars expeditions. The dunes of the Patera field are of the barchan type and their study by HiRISE was the first one to establish dune and ripple movement of a minimum of on Mars. The Patera dune field, was also the first to be investigated using the COSI-Corr software, which was origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mariner 9
Mariner 9 (Mariner Mars '71 / Mariner-I) was a robotic spacecraft that contributed greatly to the exploration of Mars and was part of the NASA Mariner program. Mariner 9 was launched toward Mars on May 30, 1971 from LC-36B at Cape Canaveral Air Force Station, Florida, and reached the planet on November 14 of the same year, becoming the first spacecraft to orbit another planet – only narrowly beating the Soviet probes ''Mars 2'' (launched May 19) and ''Mars 3'' (launched May 28), which both arrived at Mars only weeks later. After the occurrence of dust storms on the planet for several months following its arrival, the orbiter managed to send back clear pictures of the surface. Mariner 9 successfully returned 7,329 images over the course of its mission, which concluded in October 1972. Objectives Mariner 9 was designed to continue the atmospheric studies begun by Mariner 6 and 7, and to map over 70% of the Martian surface from the lowest altitude () and at the highest reso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperboreae Undae
Hyperboreae Undae (Latin: "Far Northern Waves/Dunes") is one of the largest and densest dune fields of Planum Boreum, the Martian North Pole. It is named after one of the classical albedo features on Mars. Its name was officially approved by IAU in 1988. It extends from latitude 77.12°N to 82.8°N and from longitude 302.92°E to 316.02°E (43.98°W – 57.08°W). Its centre is at latitude 79.96°N, longitude 49.49°W, and has a diameter of . Hyperboreae Undae is southwest of the Boreum Cavus depression, an arc-like depression at the northeastern boundary of Chasma Boreale. From there, Hyperboreae Undae continues in a southwestern direction through Chasma Boreale, and into the lowlands of Vastitas Borealis. It overlays the eastern part of Hyperboreae Lingua and the region above Escorial crater. Hyperboreae Undae is well known for the barchanoid and linear dunes that have formed at its location, although they are seemingly incompatible. Research has been ongoing to explain the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympia Undae
Olympia Undae is a vast dune field in the north polar region of the planet Mars. It consists of a broad "sand sea" or erg that partly rings the north polar plateau (Planum Boreum) from about 120° to 240°E longitude and 78° to 83°N latitude. Stretching about across and covering an area of 470,000 km2, Olympia Undae is the largest continuous dune field on Mars. It is similar in size to the Rub' Al Khali in the Arabian Peninsula, the largest active erg on Earth. Olympia Undae lies within the informally named Borealis basin (also called the north polar basin), the largest of three topographic basins that occur in the northern lowlands of Mars. The average elevation in Olympia Undae is about 4,250 m below datum ( martian "sea" level). The 19-km-diameter crater Jojutla lies near the geographic center of Olympia Undae at 81.63°N latitude and 169.65°E longitude. This crater was named by Andres Eloy Martinez Rojas, Mexican astronomer and science writer. ''Unda'' (pl. ''undae' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hagal Dune Field
Hagal is the informal name of a dune field on Mars located below the north pole of Mars. Its name derives from the sand dunes in Frank Herbert's novel ''Dune'' and the fictional planet Hagal. It is located at coordinates 78.0° N latitude, 84.0° E longitude, and consists of linear and round dunes with a southeast slipface orientation. It was one of the dune formations targeted for imaging by the HiRISE camera, on board the Mars Reconnaissance Orbiter, at the rate of one image every six weeks. in the third year (MY31–Mars Year 31) of its seasonal expedition. It is also known as the "Martian Morse Code" due to the linear and rounded formations of its dunes, which have the appearance of dots and dashes. Formation Although normally it is possible to obtain information about the wind direction from the orientation and form of sand dunes, the complexity of shapes of the Hagal dunes makes it difficult to determine the direction of the forming winds. In the case of the Hagal dune ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abalos Undae
Abalos Undae (Latin for "Abalos Waves") is a dune field on Mars in the periphery of Planum Boreum, the Martian North pole. It is one of the officially named northern circumpolar dune fields, along with Olympia, Hyperboreae, and Siton Undae, and also one of the densest of the region. Its northernmost boundary is located in the southwest channel that separates the Abalos Colles formation from the main polar ice cap, and from there the dune field extends southwest all the way to the lowlands of Vastitas Borealis. It is theorised that the dunes of the Abalos field may have resulted from erosion of ''Rupes Tenuis'' ( la, Thin Cliff), the polar scarp. Its name was approved by the International Astronomical Union in 1988. It extends from latitude 74.94°N to 82.2°N and from longitude 261.4°E to 283.03°E (76.97°W – 98.6°W). Its origin is located at classical albedo feature with coordinates 72°N, 70°W and has a diameter of 442.74 km. Location and formation characteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Albedo Features On Mars
The classical albedo features of Mars are the light and dark features that can be seen on the planet Mars through an Earth-based telescope. Before the age of space probes, several astronomers created maps of Mars on which they gave names to the features they could see. The most popular system of nomenclature was devised by Giovanni Schiaparelli, who used names from classical antiquity. Today, the improved understanding of Mars enabled by space probes has rendered many of the classical names obsolete for the purposes of cartography; however, some of the old names are still used to describe geographical features on the planet. History Observing albedo features Early telescopic astronomers, observing Mars from a great distance through primitive instruments (though they were advanced for their day), were limited to studying albedo contrasts on the surface of the planet. These lighter and darker patches rarely correspond to topographic features and in many cases obscure them. The o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaglyph 3D
Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different (usually chromatically opposite) colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored images, one for each eye. When viewed through the "color-coded" "anaglyph glasses", each of the two images reaches the eye it's intended for, revealing an integrated stereoscopic image. The visual cortex of the brain fuses this into the perception of a three-dimensional scene or composition. Anaglyph images have seen a recent resurgence due to the presentation of images and video on the Web, Blu-ray Discs, CDs, and even in print. Low cost paper frames or plastic-framed glasses hold accurate color filters that typically, after 2002, make use of all 3 primary colors. The current norm is red and cyan, with red being used for the left channel. The cheaper filter material used in the monochromatic past dictated red and blue for convenience and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barchan
A barchan or barkhan dune (from Kazakh бархан ) is a crescent-shaped dune. The term was introduced in 1881 by Russian naturalist Alexander von Middendorf, based on their occurrence in Turkestan and other inland desert regions. Barchans face the wind, appearing convex and are produced by wind action predominantly from one direction. They are a very common landform in sandy deserts all over the world and are arc-shaped, markedly asymmetrical in cross section, with a gentle slope facing toward the wind sand ridge, comprising well-sorted sand. This type of dune possesses two "horns" that face downwind, with the steeper slope known as the slip face, facing away from the wind, downwind, at the angle of repose of the sand in question, approximately 30–35 degrees for medium-fine dry sand. The upwind side is packed by the wind, and stands at about 15 degrees. Barchans may be high and wide at the base measured perpendicular to the wind. Simple barchan dunes may appear ... [...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-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 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), 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 autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volumetric Flow Rate
In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol (sometimes ). It contrasts with mass flow rate, which is the other main type of fluid flow rate. In most contexts a mention of ''rate of fluid flow'' is likely to refer to the volumetric rate. In hydrometry, the volumetric flow rate is known as '' discharge''. Volumetric flow rate should not be confused with volumetric flux, as defined by Darcy's law and represented by the symbol , with units of m3/(m2·s), that is, m·s−1. The integration of a flux over an area gives the volumetric flow rate. The SI unit is cubic metres per second (m3/s). Another unit used is standard cubic centimetres per minute (SCCM). In US customary units and imperial units, volumetric flow rate is often expressed as cubic feet per second (ft3/s) or gallons per minute (either ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saltation (geology)
In geology, saltation () is a specific type of particle transport by fluids such as wind or water. It occurs when loose materials are removed from a bed and carried by the fluid, before being transported back to the surface. Examples include pebble transport by rivers, sand drift over desert surfaces, soil blowing over fields, and snow drift over smooth surfaces such as those in the Arctic or Canadian Prairies. Process At low fluid velocities, loose material rolls downstream, staying in contact with the surface. This is called ''creep'' or ''reptation''. Here the forces exerted by the fluid on the particle are only enough to roll the particle around the point of contact with the surface. Once the wind speed reaches a certain critical value, termed the ''impact'' or ''fluid threshold'', the drag and lift forces exerted by the fluid are sufficient to lift some particles from the surface. These particles are accelerated by the fluid, and pulled downward by gravity, causing them to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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