The atmosphere of Jupiter consists of 90 percent hydrogen gas and nearly 10 percent helium. However, its atmosphere has trace amounts of ammonia, sulfur and water vapor. Jupiter is a gas giant that is also the biggest planet in the solar system.
Jupiter's diameter at the equator is approximately 89,000 miles. Clouds cover Jupiter's surface, and a prominent feature is the Great Red Spot, which is a massive hurricane-like storm. This storm has lasted about 350 years. Jupiter has strong winds that are between 192 to 400 miles per hour. It has a very strong magnetic field.
The temperature on Jupiter is about -108 degrees Celsius. It takes Jupiter 11.8 Earth years to rotate about the sun. It has a fast rotation about its axis. Jupiter has three known rings and over 60 moons or satellites. Some moons are Io, Europa and Ganymede. With a diameter of 5,268 kilometers, Ganymede is the biggest moon. It is bigger than the planet Mercury.
Many spacecrafts have visited Jupiter, including Cassini, Voyager 2 and Pioneer 2. In 2016, the Juno mission is expected to explore the planet.
Jupiter is a bright planet in the solar system and ancient civilizations were aware of its existence. Its name comes from the king of the Roman gods.