Jupiter data
Diameter: 88,730 miles
Time to rotate: 9 hours, 50 minutes
Orbit: 11.9 Earth years

Jupiter is the largest planet within our solar system, located five planets from the Sun. Jupiter has a total radius of nearly 70,000 kilometers, which is second only to that of the Sun’s 696,000 kilometer radius. Jupiter’s overall size is 318 times greater than that of the Earth. Jupiter is 2.5 times larger than all of the other planets in the solar system combined. It takes this massive planet a whopping 4,333 days to orbit the Sun one full time!

Jupiter’s atmosphere is composed of about 90% hydrogen and 10% helium gas, including a small rocky core that is encompassed by metallic and liquid hydrogen and hydrogen gas.

The planet Jupiter has 63 discovered moons on record. The four largest of these moons, Io, Europa, Ganymede and Callisto, are commonly referred to as the Galilean Moons. The Galilean Moons were discovered by Galileo Galilei, and can easily be seen from earth with a weak telescope or even the naked eye under especially clear conditions.

The Red Spot
Jupiter's most familiar feature is swirling mass of clouds that are higher and cooler than surrounding ones. Called the Great Red Spot, it has been likened to a great hurricane and is caused by tremendous winds that develop above the rapidly spinning planet. Winds blow counterclockwise around this disturbance at about 250 miles per hour. Hurricanes on Earth rarely generate winds over 180 miles an hour. The Red Spot is twice the size of Earth and has been raging for at least 300 years. It is one of several storms on Jupiter.

Inside Jupiter
At Jupiter's center is a core of rock many times the mass of Earth. But the bulk of the planet is a thick gaseous murk that appears smeared through a telescope because the planet moves so rapidly beneath. Jupiter's rapid rotation causes it to bulge, making the diameter 7 percent greater at the equator than at the poles.

Around Jupiter
Jupiter has thin, barely perceptible rings and at least 16 satellites. The four largest-- Io, Europa, Ganymede and Callisto -- are called the Galilean moons. They orbit in the same plane and are all visible in a telescope.