|
Occator Crater
Occator is an impact crater located on Ceres, the largest object in the main asteroid belt that lies between the orbits of Mars and Jupiter, that contains "Spot 5", the brightest of the bright spots observed by the Dawn spacecraft. It was known as "Region A" in ground-based images taken by the W. M. Keck Observatory on Mauna Kea. The crater was named after Occator, the Roman god of the harrow and a helper to Ceres. The name Occator was officially approved by the IAU on 3 July 2015. On 9 December 2015, scientists reported that the bright spots on Ceres, including those in Occator, may be related to a type of salt, particularly a form of brine containing magnesium sulfate hexahydrite (MgSO4·6H2O); the spots were also found to be associated with ammonia-rich clays. More recently, on 29 June 2016, scientists reported the bright spot to be mostly sodium carbonate (), implying that hydrothermal activity was probably involved in creating the bright spots. In August 2020, NAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawn (spacecraft)
''Dawn'' is a retired space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the ninth in NASA's Discovery Program—''Dawn'' entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It entered orbit around Ceres on March 6, 2015. In 2017, NASA announced that the planned nine-year mission would be extended until the probe's hydrazine fuel supply was depleted. On November 1, 2018, NASA announced that ''Dawn'' had depleted its hydrazine, and the mission was ended. The spacecraft is currently in a derelict, but stable, orbit around Ceres. ''Dawn'' is the first spacecraft to orbit two extraterrestrial bodies, the first spacecraft to visit either Vesta or Ceres, and the first to orbit a dwarf planet. The ''Dawn'' mission was managed by NASA's Jet Propulsion Laboratory, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions in water. Historically, it was extracted from the ashes of plants growing in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood (once used to produce potash), sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process. Hydrates Sodium carbonate is obtained as three hydrates and as the anhydrous salt: * sodium carbonate decahydrate ( natron), Na2CO3·10H2O, which readily effloresces to form the monohydrate. * sodium carbonate heptahydrate (not known in mineral form), Na2CO3·7H2O. * sodium carbonate monohydrate ( thermonatrite), Na2CO3·H2O. Also known as crystal carbonate. * anhydrous sodium carbonate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Geological significance Igneous and metamorphic rocks make up 90–95% of the to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ejecta Blanket
An ejecta blanket is a generally symmetrical apron of ejecta that surrounds an impact crater; it is layered thickly at the crater's rim and thin to discontinuous at the blanket's outer edge. The impact cratering is one of the basic surface formation mechanisms of the solar system bodies (including the Earth) and the formation and emplacement of ejecta blankets are the fundamental characteristics associated with impact cratering event. The ejecta materials are considered as the transported materials beyond the transient cavity formed during impact cratering regardless of the state of the target materials. Formation A blanket of ejecta is formed during the formation of meteor impact cratering and is composed usually of the materials of that are ejected from the cratering process. Ejecta materials are deposited on the preexisting layer of target materials and therefore it form an inverted stratigraphy than the underlying bedrock. In some cases, the excavated fragment of ejects ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobate Debris Apron
Lobate debris aprons (LDAs) are geological features on Mars, first seen by the Viking Orbiters, consisting of piles of rock debris below cliffs. These features have a convex topography and a gentle slope from cliffs or escarpments, which suggest flow away from the steep source cliff. In addition, lobate debris aprons can show surface lineations as do rock glaciers on the Earth. File:Wikictxp13clifflda.jpg, alt=Wide view of mesa with CTX showing Cliff face and location of lobate debris apron (LDA) Location is Ismenius Lacus quadrangle., Wide view of mesa with CTX showing cliff face and location of lobate debris apron (LDA) Location is Ismenius Lacus quadrangle. File:Wikifretesp 028313 2220cliff.jpg, Enlargement of previous CTX image of mesa This image shows the cliff face and detail in the LDA. Image taken with HiRISE under HiWish program. Location is Ismenius Lacus quadrangle. File:Wikildaf03 036777 2287.jpg, alt=Lobate debris aprons (LDAs) around a mesa, as seen by CTX. Mesa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinalia
The Vinalia were Roman festivals of the wine harvest, wine vintage and gardens, held in honour of Jupiter and Venus. The ''Vinalia prima'' ("first Vinalia"), also known as the ''Vinalia urbana'' ("Urban Vinalia") was held on 23 April to bless and sample last year's wine and ask for good weather until the next harvest. The ''Vinalia rustica'' ("Rustic Vinalia") was on 19 August, before the harvest and grape-pressing. Vinalia Urbana The ''Vinalia Urbana'' was held on 23 April. It was predominantly a wine festival, shared by Venus as patron of " profane" wine (''vinum spurcum'') intended for everyday human use, and Jupiter as patron of the strongest, purest, sacrificial grade wine (''temetum''). In honour of Venus, whose powers had provided humankind with ordinary wine, men and women alike sampled the ''vinum spurcum'' of the previous autumn's pressing. As god of the weather on which the wine-harvest depended, Jupiter was offered a special libation of the previous year's sacred w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facula
A facula (plural: faculae ), Latin for "little torch", is literally a "bright spot". The term has several common technical uses. It is used in planetary nomenclature for naming certain surface features of planets and moons,. and is also a type of surface phenomenon on the Sun's photosphere. In addition, a bright region in the projected field of a light source is sometimes referred to as a facula, and photographers often use the term to describe bright, typically circular features in photographs that correspond to light sources or bright reflections in a defocused image. Solar facula Solar faculae are bright spots in the photosphere that form in the canyons between solar granules, short-lived convection cells several thousand kilometers across that constantly form and dissipate over timescales of several minutes. Faculae are produced by concentrations of magnetic field lines. Strong concentrations of faculae appear in solar activity, with or without sunspots. The faculae and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tholus
In planetary nomenclature, a tholus (pl. tholi ) is a small domical mountain or hill. The word is from the Greek θόλος, ''tholos'' (pl. ''tholoi''), which means a circular building with a conical or vaulted roof. The Romans transliterated the word into the Latin ''tholus,'' which means cupola or dome. In 1973, the International Astronomical Union (IAU) adopted ''tholus'' as one of a number of official descriptor terms for topographic features on Mars and other planets and satellites. One justification for using neutral Latin or Greek descriptors was that it allowed features to be named and described before their geology or geomorphology could be determined. For example, many tholi appear to be volcanic in origin, but the term does not imply a specific geologic origin.Russell, J.F.; Snyder, C.W.; Kieffer, H.H. (1992)Origin and Use of Martian Nomenclaturein ''Mars,'' H.H. Kieffer et al., Eds.; University of Arizona Press: Tucson, AZ, p. 1312. Currently (March 2015), the IAU rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
