Jupiter is a planet in Earth's solar system. It had a rough, cratered surface with volcanic activity. Jace went to check out Crater Area 3 to get a closer look. On the planet, he discovered a giant heat generating monster that could hurl lave. (Space Ghost: "The Heat Thing")
- The actual planet Jupiter has no such surface to speak of. It's a gas giant, with pressure and hence density increasing as you go deeper into the gas. At some point it does become solid, but it'd be hard to determine exactly where the "surface" would be. Volcanic activity, hence, is also unlikely.
In the original cartoon, Jupiter also appear to be populated as The Evil Collector kidnapped an alien from Jupiter and shrunk him. (Space Ghost: "The Evil Collector")