On August 14th, 2009 Jona Earth Said:

How about this: Jupiter is named Jupiter because it’s the largest of the Solar System planets. It is also a Gas Giant, same as Uranus, Neptune and Saturn, which means it is a massive planet made mostly of gas – i.e. with no or little solid crust like we have on Earth.

So far hundreds of exta-Solar System planets have been discovered around other stars, but they are all Gas Giants because we don’t yet have the technology to detect the smaller, life-supporting planets. However, the Kepler Mission http://kepler.nasa.gov may change all that.