Jupiter is the fifth planet from the Sun and by far the largest massive object in the solar system among all the other planets. Jupiter is twice as large as all the other planets combined. It is 318 times larger than the earth. The distance at which Jupiter orbits the sun is 778,330,000 km (Gallant pp154). The diameter is 142,984 km and the mass it has is 1,900e27 kg. Jupiter is the fourth brightest object in the sky after the Sun, Moon and Venus. Mars is a few times brighter. Galileo discovered Jupiter in 1610 (Gallant); another interesting fact is that Jupiter has 4 large moons. Which are known as the Galilean moons. They were called Io, Europa, Ganymede and Callisto. The first mission to Jupiter was Pioneer 10 in 1973 and later Pioneer 11, Voyager 1 and Voyager 2 (Gallant). There is currently a spacecraft called Galileo that is currently orbiting Jupiter and will be sending data for the next two years. On December 7, 1995, the Galileo probe entered the atmosphere at a speed of 106,000 miles per hour and survived. Also in the next few years a probe will circle the moon Europa. We will be able to see if there is actually an ocean on that moon (National Geographic, January 2000). Many scientists did not believe that it could succumb to the force of gravity which is 228 times that of Earth. Jupiter, Saturn, Neptune and Uranus are known as gaseous planets and do not have a solid surface. Jupiter is made up of 90% hydrogen and 10% helium (Gallant). This is very close to the composition of the primor...