Let me remind you that the Solar System
today looks like this:
(good web page: http://photojournal.jpl.nasa.gov/)
There are four small, rocky, inner planets;
four large, gaseous, outer planets;
and Pluto, the farthest from the Sun.
We will spend some time on comparative
planetology of some of these bodies
in a few weeks. For now, we simply want
this overview.
Jupiter is 318 times as massive as the Earth.