The Solar System

The earth is a part of our Solar System, consisting of the Sun, nine planets, the asteroid belt, and occasional comets.

 

Figure 14.1: The Solar System

The Sun, at the center, contains the majority of the mass of the Solar System. The planets can be grouped into two main categories:

 
• Terrestrial Planets: Mercury, Venus, Earth, and Mars are called terrestrial planets. These are comparatively small and consist mostly of heavier elements in a solid form.  
• Jovian Planets: Jupiter, Saturn, Uranus, and Neptune are Jovian planets, or gas giants. These are comparatively large, and consist mainly of lighter elements in a gaseous or liquid state.

Pluto, the planet farthest from the Sun, is an anomaly in this scheme, as it is a relatively small planet located with the gas giants. Between Mars and Jupiter is the asteroid belt, thought to be the remnants of the material that made up the Solar System which, because of the competing gravitational pull of Jupiter and the Sun, did not form a planet.