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Chondrules in the chondrite classification Grassland. A millimeter scale is shown. Chondrules in the Carbonaceous Chondrite NWA 13887. A 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.
A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. [6] The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. [7]
Chondrules, metal grains, and other components likely formed in the solar nebula. These accreted together to form parent asteroids. These accreted together to form parent asteroids. Some of these bodies subsequently melted, forming metallic cores and olivine -rich mantles ; others were aqueously altered. [ 35 ]
It comprises the formation of chondrules in the region of the terrestrial planets. Theories of chondrule formation include solar nebula lightning; nebular shocks, [66] and meteoroid collisions. [67] In this phase dust decouples from the gas and move on Kepler orbits around the central protostar slowly settling near the middle plane of the disk.
This is a list of diffuse nebulae. Most nebulae are diffuse , meaning that they do not have well-defined boundaries. Types of diffuse nebulae include emission nebulae and reflection nebulae .
A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae.
Aqueous alteration promotes a composition of hydrous phyllosilicates, magnetite, and olivine crystals occurring in a black matrix, and a possible lack of chondrules. It is thought they have not been heated above 50 °C (122 °F), indicating that they condensed in the cooler outer portion of the solar nebula.
While CM chondrules are smaller than average in diameter (~300 micrometer), CO chondrules are exceptionally small (~170 um). [ 31 ] [ 32 ] This may be a survivor bias : consider that the water which dissolves CM chondrules successfully eliminates those which are already small, while those which were large may remain to be observed, though with ...