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Minor Members Things that didn’t make up the sun, planets or moons. Asteroids • Rocky objects usually larger than a mile across. • Most are found in the Asteroid Belt between Mars and Jupiter • Earth has been hit by asteroids in the past. Comets • Are mostly made of ice. • Orbit the sun. • Their return can be predicted. • Their tail shows the direction of the sun, not which way they are headed. Meteoroids • Small (less than 1 mile) rocks in space. • When they enter a planets atmosphere they are meteors. • When they strike the ground, they are meteorites. We Have Been Hit • The moon shows it’s record of impacts because it has no erosion. • Earth shows only recent signs of impact. • One major theory says that we were hit 65 MYA and this killed the dinosaurs. Iridium • Iridium is very rare here on Earth but plentiful in asteroids. • A layer of Iridium is found at the K-T boundary (65 MYA) Back Back Back to slide 5