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Dust Ponds
Dust ponds are a phenomenon where pockets of dust are seen in celestial bodies without a significant atmosphere, like asteroids, comets and some minor planets. These are smooth deposits of dust accumulated in depressions on the surface of the body (like craters), contrasting from the rocky terrain around them. They typically have different color and albedo compared to the surrounding areas. As there are no air around them, their method of formation is still debated. The phenomenon was discovered on 2000 October 28, by the spaceprobe NEAR Shoemaker on Asteroid 433 Eros. Cause On airless bodies, electrostatic transport is believed to be the leading cause of dust transport. Infrared rays and ultraviolet rays from the Sun are strong enough to knock electrons off the dust present on surface. These positively charged particles get repelled from the surface kilometers high. On the night side, the dust is negatively charged by electrons from the solar wind. Particles at the night side wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroids
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outgassing
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which are phase transitions of a substance into a gas), as well as desorption, seepage from cracks or internal volumes, and gaseous products of slow chemical reactions. Boiling is generally thought of as a separate phenomenon from outgassing because it consists of a phase transition of a liquid into a vapor of the same substance. In a vacuum Outgassing is a challenge to creating and maintaining clean high- vacuum environments. NASA and ESA maintain lists of materials with low-outgassing properties suitable for use in spacecraft, as outgassing products can condense onto optical elements, thermal radiators, or solar cells and obscure them. Materials not normally considered absorbent can release enough lightweight molecules to interfere wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Horizon Glow
Lunar horizon glow is a phenomenon in which dust particles in the Atmosphere of the Moon, Moon's thin atmosphere create a glow during lunar sunset. The Surveyor program provided the first data and photos of the phenomenon. Astronauts in lunar orbit observed it during the Apollo 15 and Apollo 17 missions. Cause Dust kicked off from the surface of the Moon will stay in the atmosphere for around 3 hours. Apart from this, electrically charged particles could be levitated by electrostatic fields with a strength of >500 V cm−1. This cloud of dust, near the Terminator (solar), lunar terminator line, forward scatters the light, creating a glow near the horizon during lunar sunset. The dust, 10 micrometers in diameter, is thought to be above 10 km from the lunar surface. The levitation mechanism is thought to eject 107 more particles per unit time into the cloud than those caused by micrometeoroid impacts. The term "Moon fountain" has been used to describe this effect. During ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Itokawa06 Hayabusa
Itokawa (written: lit. "thread river") is a Japanese surname. Notable people with the surname include: *, Japanese rocket scientist *, Japanese politician of the People's New Party *, Japanese shot putter *, Japanese speed skater See also *25143 Itokawa, an asteroid named after Hideo Itokawa {{surname Japanese-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hayabusa
was a robotic spacecraft developed by the Japan Aerospace Exploration Agency (JAXA) to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis. ''Hayabusa'', formerly known as MUSES-C for Mu Space Engineering Spacecraft C, was launched on 9 May 2003 and rendezvoused with Itokawa in mid-September 2005. After arriving at Itokawa, ''Hayabusa'' studied the asteroid's shape, spin, topography, color, composition, density, and history. In November 2005, it landed on the asteroid and collected samples in the form of tiny grains of asteroidal material, which were returned to Earth aboard the spacecraft on 13 June 2010. The spacecraft also carried a detachable minilander, ''MINERVA'', which failed to reach the surface. Mission firsts NASA's ''Galileo'' and ''NEAR Shoemaker'' spacecraft had visited asteroids before, but the ''Hayabusa'' mission was the first one to return an asteroid sample to Earth for analysis. In addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JAXA
The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orbit, and is involved in many more advanced missions such as asteroid exploration and possible human exploration of the Moon. Its motto is ''One JAXA'' and its corporate slogan is ''Explore to Realize'' (formerly ''Reaching for the skies, exploring space''). History On 1 October 2003, three organizations were merged to form the new JAXA: Japan's Institute of Space and Astronautical Science (ISAS), the National Aerospace Laboratory of Japan (NAL), and National Space Development Agency of Japan (NASDA). JAXA was formed as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Ministry of Internal Affairs and Communications (MIC). Before the mer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
25143 Itokawa
25143 Itokawa (provisional designation ) is a sub-kilometer near-Earth object of the Apollo group and also a potentially hazardous asteroid. It was discovered by the LINEAR program in 1998 and later named after Japanese rocket engineer Hideo Itokawa. The peanut-shaped S-type asteroid has a rotation period of 12.1 hours and measures approximately in diameter. Due to its low density and high porosity, Itokawa is considered to be a rubble pile, consisting of numerous boulders of different sizes rather than of a single solid body. It was the first asteroid to be the target of a sample-return mission, of the Japanese space probe ''Hayabusa'', which collected more than 1500 regolith dust particles from the asteroid's surface in 2005. Since its return to Earth in 2010, the mineralogy, petrography, chemistry, and isotope ratios of these particles have been studied in detail, providing insights into the evolution of the Solar System. Itokawa was the smallest asteroid to be photograph ... [...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 derelict probe remains in a stable orbit around Ceres. ''Dawn'' is the first spacecraft to have orbited two extraterrestrial bodies, the first spacecraft to have visited either Vesta or Ceres, and the first to have orbited a dwarf planet. The ''Dawn'' mission was managed by NASA's Jet Propulsion Laboratory, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4 Vesta
Vesta (minor-planet designation: 4 Vesta) is one of the largest objects in the asteroid belt, with a mean diameter of . It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta (mythology), Vesta, the virgin goddess of home and hearth from Roman mythology. Vesta is thought to be the second-largest asteroid, both by mass and by volume, after the dwarf planet Ceres (dwarf planet), Ceres. Measurements give it a nominal volume only slightly larger than that of 2 Pallas, Pallas (about 5% greater), but it is 25% to 30% more massive. It constitutes an estimated 9% of the mass of the asteroid belt. Vesta is the only known remaining rocky protoplanet of the kind that formed the terrestrial planets. Numerous fragments of Vesta were ejected by collisions one and two billion years ago that left two enormous craters occupying much of Vesta's southern hemisphere. Debris from these events has fallen to Earth as HED meteorite, howardi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar day) that is synchronized to its orbital period (Lunar month#Synodic month, lunar month) of 29.5 Earth days. This is the product of Earth's gravitation having tidal forces, tidally pulled on the Moon until one part of it stopped rotating away from the near side of the Moon, near side, making always the same lunar surface face Earth. Conversley, the gravitational pull of the Moon, on Earth, is the main driver of Earth's tides. In geophysical definition of planet, geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is , roughly one-quarter of Earth's (about as wide as the contiguous United States). Within the Solar System, it is the List of Solar System objects by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olivine
The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. Olivine has many uses, such as the gemstone peridot (or chrysolite), as well as industrial applications like metalworking processes. The ratio of magnesium to iron varies between the two endmember (mineralogy), endmembers of the solid solution series: forsterite (Mg-endmember: ) and fayalite (Fe-endmember: ). Compositions of olivine are commonly expressed as Mole (unit), molar percentages of forsterite (Fo) and/or fayalite (Fa) (''e.g.'', Fo70Fa30, or just Fo70 with Fa30 implied). Forsterite's melting temperature is unusually high at atmospheric pressure, almost , while fayalite's is much lower – about . Melting temperature varies smoothly between the two end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
20120927 Surveyor7-levitating-dust
1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sports, where it commonly denotes the first, leading, or top thing in a group. 1 is the unit of counting or measurement, a determiner for singular nouns, and a gender-neutral pronoun. Historically, the representation of 1 evolved from ancient Sumerian and Babylonian symbols to the modern Arabic numeral. In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. In digital technology, 1 represents the "on" state in binary code, the foundation of computing. Philosophically, 1 symbolizes the ultimate reality or source of existence in various traditions. In mathematics The number 1 is the first natural number after 0. Each natural number, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
