Asteroids, Meteoroids, and Comets

1. Asteroids, Meteoroids, and Comets

2. Asteroids • An asteroid is a large chunk of rock or metal that orbits the Sun. • The largest asteroid is Ceres with a diameter of 940 km. (Mercury has a diameter of ~4,880 km.)

3. Asteroids • These asteroids are leftover debris from the formation of the solar system. • Most orbit the Sun in the asteroid belt between Mars and Jupiter.

4. Meteoroids • Asteroids can collide and break off smaller pieces. • These pieces are called meteoroids and can be smaller than a piece of sand. • Meteoroids are scattered throughout the solar system.

5. Meteors • Meteoroids that enter a planet’s atmosphere will become meteors as they streak through the sky. • The friction caused by the atmosphere will cause some of the meteoroid to burn which produces the streak.

6. Meteorite • Large pieces of meteors that reach a planet’s surface are known as meteorites. • Craters may result from impact if the meteorite is large enough.

7. Comets • A lump of ice, frozen gas, and dust that orbits the Sun is a comet. • Comets orbit the Sun in very long ellipses that may take it beyond the orbit of Pluto.

8. Comets • Comets have three parts: • The nucleus (core) that is a dirty ice ball. • The coma is the cloud of gas that surrounds the nucleus. • The tail is the long, ribbonlike trail of comet dust and gas.

9. Comets C) Continued….The tail always point away from the Sun. • Comets come from the Oort Cloud that is beyond Pluto’s orbit.