- 行业: Astronomy
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Planetary Science Research Discoveries (PSRD) is an educational site sharing the latest research by NASA-sponsored scientists on meteorites, asteroids, planets, moons, and other materials in our Solar System. The website is supported by the Cosmochemistry Program of NASA's Science Mission ...
Inclusions, enriched in the rare earths and the other elements mentioned in the definition of refractory, which are identified in rocks petrographically because of their mineralogy, which is dominated by Ca-, Al-, and Ti-rich phases. This is why these inclusions are often referred to as Ca-, Al-rich inclusions, or "CAIs. " Most refractory inclusions contain the minerals spinel and melilite and/or hibonite.
Industry:Astronomy
One of two successful series of Soviet unpiloted lunar missions. There were 24 missions to the Moon in the Luna series launched from 1959 to 1976. (The other series, Zond, had 5 lunar missions launched in 1965 to 1970. ) The first image of the farside of the Moon was taken by the Luna 3 spacecraft in October, 1959. Three Luna landers (Luna 16, 20, and 24) collected a total of approximately 300 grams of lunar samples and returned them to Earth.
Industry:Astronomy
General term referring to the large-scale change of rock in response to forces causing faulting and folding. The forces acting upon a rock mass are generally termed compressional (squeezing together), tensional (pulling apart), or shear (parallel sliding). Common landforms resulting from tectonic processes are mountain ranges, rift zones, faults, fractured rock, and folded rock masses.
Industry:Astronomy
The scientific study of rocks. This is the field within geology that focuses on the origin, occurrence, formation, structure, and composition of mineral assemblages, and classification of rocks.
Industry:Astronomy
An element with atomic number 26; symbol: Fe. Iron is one of the most abundant elements in the rocky planets. It is the most abundant element in the metallic cores of the inner planets.
Industry:Astronomy
Sediment on the surface of the lunar maria; fragments of basalt rocks, broken mineral grains, and glass produced by impact.
Industry:Astronomy
One group of hydrocarbons (benzene) produced by decomposition or decay of organic matter. These are certainly aromatic: they stink!
Industry:Astronomy
Study of layered rock to understand the sequence of geological events. Normally, older layers are on the bottom unless the sequence has been overturned or disrupted.
Industry:Astronomy
A natural solid object (metallic or stony/silicate) larger than 10 µm (microns) that has traveled through space, by natural means from the celestial body on which it formed, and has landed on Earth or other planetary body or artificial body/satellite (larger than itself). Most meteorites come from asteroids, but a small number found on Earth come from the Moon (see Lunar meteorites) or Mars (see Martian meteorites). Meteorite types include: iron, stony iron, chondrite, carbonaceous chondrite, and achondrite. A primitive meteorite is defined as a chondrite that experienced minimal heating and aqueous alteration on its parent asteroid. Primitive meteorites have the highest concentrations of presolar grains. (See "Meteors, Meteorites, and Impacts" from The Eight Planets website. ) Meteorites between 10 µm (microns) and 2 mm in size are called "micrometeorites. " Meteorites collected on Earth are named for the location where they are found.
Industry:Astronomy
General term to describe the process of mass movement (or avalanche) of material downslope by falling, sliding, or flowing, under the force of gravity. It also describes the landform (pile of debris) produced.
Industry:Astronomy
