- 行业: Astronomy
- Number of terms: 6727
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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 ...
A point on the surface of a sphere that is located diametrically opposite another point. For example, on the Earth the antipode of Hawaii is Botswana. The term is used commonly in lunar geology to describe locations on the Moon in relation to impact basins. Researchers have hypothesized that accumulations of converged ejecta materials, production of impact shock stresses, anomalies in lunar crustal magnetic fields, and geochemical anomalies are associated with antipodes of basins.
Industry:Astronomy
Seventeen closely related elements, the lanthanoid series, from atomic numbers 57 through 71 on the Periodic Table (some people define the series from atomic numbers 58 through 71). These elements usually occur together and are useful in geochemical modeling.
Industry:Astronomy
Extremely high-energy subatomic particles that continuously bombard Earth from all directions. Most cosmic rays hit and break up atomic nuclei in Earth's upper atmosphere. Airless bodies are not protected and their surfaces (asteroids, for example) are exposed.
Industry:Astronomy
Mineral found in basalt; ranges from Mg<sub>2</sub> SiO<sub>4</sub> to Fe<sub>2</sub> SiO<sub>4</sub>.
Industry:Astronomy
The most common class of meteorite to fall on Earth. They contain variable amounts of metal and chondrules in a matrix of mostly silicate minerals. See chondrite.
Industry:Astronomy
Mass per unit volume; a measure of how much material is in a given space.
Industry:Astronomy
The pattern of the relative abundances of ions of different atomic or molecular mass (mass-to-charge ratio) within a sample. It frequently refers to the measured relative abundances of isotopes of a given element.
Industry:Astronomy
