Asteroids and Comets Remnants of the original formation of the solar nebula. No differentiation, no geologic processes, no atmospheres. Asteroids are the rocky left-overs.
Comets are the icy left-overs.
We see a streak of light. Several hundred tons of meteorites enter the Earth's atmosphere each day. Meteorites are any chunk of rock from an asteroid, a comet, or another planet that survives going through the atmosphere and actually reaches the ground. Asteroids First asteroids discovered when observers were looking for a planet between Mars and Jupiter. All the asteroids lumped together would make an object less than half the size of the Moon.