What Is Jupiter?
Jupiter with a shadow from one of its moons

Jupiter is known for its stripes and large red spot. Image Credit: NASA/JPL/University of Arizona

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Jupiter is the largest planet in the solar system. Jupiter is so large that all of the other planets in the solar system could fit inside it. More than 1,000 Earths would fit inside Jupiter.

Jupiter is the fifth planet from the sun. From Earth, it is almost always the second brightest planet in the sky. Venus is brighter. The planet is named after Jupiter. He was the king of the Roman gods.

Jupiter is made of the same things that stars are made of. In fact, Jupiter would have become a star if it were about 80 times bigger.

What Is Jupiter Like?

Jupiter is a giant gas planet. The planet is covered in thick red, brown, yellow and white clouds. Jupiter is a very windy planet with winds that blow more than 400 mph. That is faster than hurricanes and tornadoes!

Jupiter's Great Red Spot

The Galileo spacecraft took this photo of Jupiter's Great Red Spot in 1996. Image Credit: The Galileo Project/JPL/NASA/APOD

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Jupiter is famous for its Great Red Spot. The swirling red spot is a giant spinning storm. It looks like a hurricane. Almost three-and-a-half Earths would fit across the storm.

Jupiter has three thin rings. The rings were found in 1979 by NASA's Voyager 1 spacecraft. Jupiter's rings are made up mostly of tiny bits of dust.

Jupiter rotates, or spins, faster than any other planet. A day on Jupiter is about 10 hours long. It is so far from the sun that it takes 12 Earth years for Jupiter to make one trip around the sun. That means one year on Jupiter is 12 years on Earth.

It is very cold on Jupiter. Gravity is different, too. There is more gravity on Jupiter than on Earth. Someone who weighs 100 pounds on Earth would weigh about 240 pounds on Jupiter.

How Many Moons Does Jupiter Have?

An artist's drawing of part of Jupiter and the four Galilean satellites

Jupiter's four largest moons (Io, Europa, Ganymede and Callisto) are known as the Galilean satellites because they were discovered by Galileo Galilei in 1610. Image Credit: NASA

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Right now, 62 moons have been found around Jupiter. The last time a moon was found was in 2003. The planet's four largest moons are Io, Europa, Ganymede and Callisto. They were found in 1610.

The largest of Jupiter's moons is named Ganymede. It is the largest moon in the solar system. Ganymede is larger than Mercury and Pluto. Io has a lot of volcanoes. Europa is covered with water ice.

How Has NASA Explored Jupiter?

Scientists use telescopes on Earth to study Jupiter. The Hubble Space Telescope has taken pictures of Jupiter. NASA has sent eight spacecraft to Jupiter. The missions studied Jupiter's atmosphere, surface, moons and rings. The missions took close-up pictures of some of the unusual things found on Jupiter.

How Is NASA Exploring Jupiter Today?

An artist's drawing of the Juno spacecraft flying in front of Jupiter

NASA's Juno mission will study how Jupiter, the largest planet in the solar system, formed and became the dynamic world it is today. Image Credit: NASA

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A new spacecraft is going to Jupiter. NASA's Juno spacecraft launched in August of 2011. It will get to Jupiter in 2016. Juno will orbit closer to Jupiter than any other spacecraft. Juno will take the first pictures around Jupiter's north and south poles.

More About Jupiter:
› Solar System Exploration Jupiter   →
› Jupiter's Moons   →
› Jupiter Image Gallery   →
› Juno Mission

Heather R. Smith/NASA Educational Technology Services
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