First of the giant planets, Jupiter is the largest planet in the Solar System. It is more than twice as massive as the other planets combined. It is a spinning ball of gas with a super-hot liquid center under incredible pressure.
The fifth planet from the Sun, Jupiter probably formed in the solar nebula by gathering material from the cloud of gas and dust around it. Most of the original air of this giant planet likely remains in place. Because of its position in the solar nebula, Jupiter was able to draw a huge amount of gas into itself and become the biggest of the planets.
For such a huge planet, Jupiter spins extremely quickly, completing its day in less than ten hours. The planet's turning speed and the heat rising form its core (hotter than the sun's surface) create unusual weather patterns. (Image Right: Jupiter, Courtesy of NASA)
