"Need"? The moon is not *required* for life or anything... It's just a "nice to have." It provides us cool things like tides and gave the early people on earth their first months. Also having the moon lets us know when it is a good time to go fishing.

There are 8 planets that orbit our sun. Pluto is no longer considered a planet - sorry, Pluto fans... In order of their distances from the Sun, the eight planets are:

1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune