QUESTION: When the Galileo Probe enters Jupiter's atmosphere in December, will we be able to see pictures of the surface of Jupiter for the first time? ANSWER from FAQ: Although Jupiter is a planet, it is very different from Earth. In fact, scientists refer to hard and rocky planets like Earth, Mercury, Venus, and Mars as "terrestrial," while planets like Jupiter, Saturn, Neptune, and Uranus are called "gas giants," since they seem to be, essentially, huge balls of gas and liquid with a small rocky core. So, Jupiter doesn't really have a "surface" in the sense of its being something that humans could walk around on, or that a spacecraft could land on. Galileo's atmospheric Probe will travel between 130 and 160 kilometers below Jupiter's cloud tops, deep enough to help answer questions such as what's in Jupiter's yellow clouds, or how strong are the winds below the cloudtops. However, the Probe won't come anywhere near seeing the "surface" of Jupiter's rocky core, buried roughly 60,000 kilometers underneath the cloud tops.