AsteroidAn asteroid is a minor planet—an object larger than a meteoroid (thus 1 meter or larger) that is neither a planet nor an identified comet—that orbits within the 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 (carbonaceous), M-type (metallic), or S-type (silicaceous).
ChondruleA chondrule (from Ancient Greek χόνδρος chondros, grain) is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids.
MeteoriteA meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides".
Planetary differentiationIn planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities). The process of planetary differentiation is mediated by partial melting with heat from radioactive isotope decay and planetary accretion.
Solar SystemPlanetary system consisting of the Sun and objects orbiting itThe Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy.
MetalType of materialIron, shown here as fragments and a 1 cm cube, is an example of a chemical element that is a metal.Metal in the form of a gravy boat made from stainless steel, an alloy largely composed of iron, chromium and nickelA metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.Parent bodyA parent body in meteoritics is the celestial body from which originates a meteorite or a class of meteorites. IdentificationIt is easiest to correlate a meteorite with a parent body when the parent body still exists. This is the case for Lunar and Martian meteorites. Samples from suspected Lunar meteorites can be compared with samples from the Apollo program. Martian meteorites can be compared to analysis carried out by rovers (e.g. Curiosity).
EarthThird planet from the SunSurface equivalent doserate0.274 μSv/hAbsolute magnitude (H)−3.99AtmosphereSurface pressure101.325 kPa (at sea level)Composition by volume78.08% nitrogen (dry air)20.95% oxygen (dry air)≤1% water vapor (variable)0.9340% argon0.0430% carbon dioxide0.00182% neon0.00052% helium0.00017% methane0.00011% krypton0.00006% hydrogen Source:Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Organic compoundOrganic compounds are a subclass of chemical compounds of carbon. Little consensus exists among chemists on the exact definition of organic compound; the only universally accepted definition is the quasi-tautological "organic compounds are the subject matter of organic chemistry". Generally, any large chemical compound containing a carbon–hydrogen or carbon–carbon bond is accepted as an organic compound.
AbiogenesisLife arising from non-living matterStages in the origin of life process range from the well understood, such as the habitable Earth and the abiotic synthesis of simple molecules, to the largely unknown, like the derivation of the last universal common ancestor (LUCA) with its complex molecular functionalities.Abiogenesis or the origin of life (sometimes called biopoiesis) is the natural process by which life arises from non-living matter, such as simple organic compounds.
MeltingMelting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point. At the melting point, the ordering of ions or molecules in the solid breaks down to a less ordered state, and the solid melts to become a liquid.
Sphere of influence (astrodynamics)A sphere of influence (SOI) in astrodynamics and astronomy is the oblate spheroid-shaped region where a particular celestial body exerts the main gravitational influence on an orbiting object. As such it is the dominating part of a gravitational field. It is usually used to describe the areas in the Solar System where planets dominate the orbits of surrounding objects such as moons, despite the presence of the much more massive but distant Sun.*As an Amazon Associate I earn from qualifying purchases.