Jupiter is the largest and most massive planet in the solar system. It was named after the chief Roman god. It is a gas giant composed of liquid and gaseous matter, and has many moons. Some of the storms in its atmosphere have lasted hundreds of years.
Jupiter has a diameter of nearly 89,000 miles and a mass of about 8.6 x 10 to the 23 power pounds. It is the fifth planet from the sun. It is just over 459,000,000 miles from the sun at its perigee and almost 506,000,000 miles from the sun at its apogee. A Jovian day is equal to almost 10 earth hours.
The major components in Jupiter's atmosphere are hydrogen and helium. The planet's atmosphere also contains much smaller amounts of methane, ethane, acetylene, water vapor, tetrahydride, carbon monoxide and phosphene.
The most distinguishing feature of Jupiter is the Great Red Spot. This so-called spot is a storm that is approximately three times the size of Earth. It has a counterclockwise rotation, making a complete rotation around Jupiter every six days. The storm was first observed in 1665.
As of 2012, there are 67 satellites orbiting Jupiter. Among the most prominent are Io, Europa, Ganymede and Callisto.