Chapter 15
The Solar System
The Planets of our Solar System.
A Planet is any large body that orbits a star and doesn't give off it's own light.
We use to limit that to the nine known planets that orbit our sun, but now with the aid of
Hubble telescope we have discovered planets around other stars.  There is still some
debate as to the smallest a body can be and still be considered a planet so some
astronomers will consider some of the larger asteroids planets also.
Planets fall into three major categories
  1. Terrestrial planets (also called inferior planets) - small, dense, rocky planets
    that formed near the sun. (Mercury, Venus, Earth and Mars)
  2. Gas Giants (also called superior planets) - large planets made of gases and
    liquids.  Formed when those less dense elements were blown farther away by the
    sun's energy. (Jupiter, Saturn, Uranus, Neptune)
  3. Pluto - A chunk of rock in a class by itself.
<<< Click on one of the planets at the left to get more information on it.
Information on the PlanetsComets, Meteors and AsteriodsThe Moons of the Solar SystemAssignment Sheets, Games and Practice Tests