Planets are balls of rock or gas that orbit around the sun. The only planet that has life on it is Earth because all the other planets are too hot or too cold or they don't have the right atmosphere. Earth is made of rock. What a surprise!

     Earth is one of the inner planets. The inner planets are Mercury ,Venus, Earth, and Mars. They are all made of rock. They are the first four planets in order from the sun. They are the hotter planets and the smallest ones.

     Gas giants are planets made of gas and not rock. There are four gas giants in all. These planets are Jupiter, Saturn, Uranus, and Neptune. As I said, the outer planets are bigger than the inner planets and are made mostly of gas with a hard inner core.

     You need a telescope to see Uranus and  Neptune. You do not need a telescope to see Mercury, Venus, Earth, Mars, Jupiter, and Saturn. With and without a telescope, all the planets still glow because of the sun's light reflecting off of them.

     Outside of the eight planets are the location of the drawf planets. Three of the drawf planets are Pluto, Eris, and Ceris. They are orbited by 1 or 2 moons.  There are many other dwarf planets as well. Just recently scientists discovered that Pluto was not alone out there and because there were so many other rocks out there just like Pluto, scientists had to make a decision whether to call all of these rocks planets or change Pluto's classification from planet to dwarf planet. They decided it would be easier to just have eight planets and reclassify Pluto. All of these planets and dwarf planets are part of our Solar System which is a part of the Milky Way Galaxy.

     There are inner planets and outer planets. Inner planets are made of rock and the outer planets are made of gas. That's not all. There is much more information available and more is being learned all the time as technology improves and more and more space probes are sent up in space.

     If you would like any more information you can click on the links below:

http://starchild.gsfc.nasa.gov/docs/StarChild/StarChild.html

http://www.gamequarium.com/space.html

Bibliography:

Branley, F. M. (1981). The planets in our solar system. New York, NY: Harper Collins Publishers.

http://en.wikipedia.org/wiki/Planets

Frank, M. S., Jones, R. M., Krockover, G. H., Lang, M.P., McLeod, J.C., Valenta, C. J., & Van Deman, B. A. (2002). Harcourt Science. Harcourt, Inc.