Pieces {asteroid}| from former planetary formation lie between Mars and Jupiter, 2.6 x 10^6 miles from Sun. Asteroids cluster and so came from collisions between many bodies 50,000 to 200,000 meters diameter. More than 10,000 asteroids exist. 2000 are relatively large.
names
Ceres has diameter 800,000 meters and is largest. Pallas, Juno, Vesta, and Hygiea have diameter more than 200 miles. Trojans are at the two stable Lagrangian points in Jupiter's orbit. Apollos go inside orbit of Mercury. Icarus goes to within 1.9 x 10^6 miles of Sun.
orbit
Asteroids have elliptical orbits. Jupiter gravity and asteroid collisions cause some orbits to be so elliptical that they go within 30,000,000,000 meters of Sun.
meteors
Meteors are asteroids. Iron meteorites {S class meteorite} are 10^9 years old. Stony meteorites are 1 x 10^6 to 100 x 10^6 years old. They are the main asteroids in inner asteroid belt. Carbonaceous chondrite meteorites {C class meteorite} {D class meteorite} are 4.6 x 10^9 years old and have solid grains from original solar-cloud dust. They are the main asteroids in outer belt and are darker and redder. Type C1 has same composition as Sun, with no silicate pea-size chondrules. Types C2 and C3 have iron, nickel, and rock, unlike Sun, and have chondrules.
Physical Sciences>Astronomy>Solar System>Planetoid
5-Astronomy-Solar System-Planetoid
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Date Modified: 2022.0224