Jupiter

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.

(Image Right: Jupiter, Courtesy of NASA)

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.

Features

: Composition of Jupiter (Original image, Courtesy of NASA)

Streaked with yellow, orange, red, and white bands of clouds, Jupiter's atmosphere churns with violent storms. Three thin rings of dust surround this giant. Mostly hydrogen and helium, the planet's atmosphere is poisonous to us. There is dangerous radiation, too. Jupiter's atmosphere could crush a metal spaceship like a plastic toy.

The Great Red Spot is a giant hurricane spinning counterclockwise. This huge storm is big enough to swallow two Earths.

With over 60 moons, Jupiter is like a mini Solar System. Its four largest moons, Io, Europa, Ganymede, and Callisto, are called the Galilean moons after the Italian astronomer who first discovered them in 1610. Ganymede is the Solar System's largest moon. Lava-splashed Io has the most volcanic activity in the Solar System. Icy-smooth Europa may have an ocean under its surface, while Callisto is covered with craters.

Learn more about Jupiter's features on NASA's Solar System Exploration website.

Missions

: Pioneer 10 flying past Jupiter (Courtesy of NASA)

Much of the scientific knowledge we now have of Jupiter came from missions within the last 30 years. Pioneer 10 and Pioneer 11 gave us the first glimpse of Jupiter in 1973 and 1974. Five years later, Voyager 1 and Voyager 2 sent images of Jupiter's moons back to Earth.

In December 1995, the spacecraft Galileo went into orbit around the Jupiter. It released an astmospheric probe that was crushed by Jupiter's atmosphere, but the main spacecraft sent back pictures and data until 2003. On its way to Saturn, Cassini flew by and also took images of Jupiter. Future missions to Jupiter will focus on its moons.

Discover more about missions to Jupiter at NASA's Solar System Exploration website.

Myths, Stories, and More

In Roman mythology, Jupiter was the king of heaven and Earth and of all the Olympian gods. The god of justice, Jupiter was named king of the gods in the special meeting following his overthrow of Saturn and the Titans. Jupiter's largest moons are also named after mythological figures.

Learn more about Jupiter myths and lore at Windows to the Universe.

Earth Matters

: Jupiter and Earth Size Comparison (Courtesy of NASA)

Currently, there is mounting evidence to suggest that a layer of liquid water could exist beneath Europa's surface ice. It could be the only place in the Solar System besides Earth where liquid water exists in significant quantities. On Earth, wherever there is water, there is life. Could life have evolved in the waters of Europa?

Find out more about why we study Europa on NASA's website.