Jupiter explained to kids

Jupiter is the fifth planet from the Sun and the largest planet in our solar system. Jupiter is so giant that it could contain 1,300 Earths! The distance through its center, or diameter, is about 140,000 km (89,000 miles). Jupiter would have become our second Sun in our solar system if it had been 80 times more massive. It's possible to see Jupiter without a telescope! It's the fourth-brightest natural object in our sky, after the Sun, moon, and planet Venus. Jupiter was named after the king of the Roman gods. The astronomer Galileo Galilei was the first person to really study Jupiter and its moons in 1610; he used a homemade telescope. Scientists believe that Jupiter is the oldest planet in our solar system: 4.6 billion years old! Brr! Jupiter's average temperature is an extremely cold -238 °F. Jupiter is a gas giant because it's made mostly of the gases hydrogen and helium, along with some liquids. All that gas and liquid means there's no true surface on Jupiter. So, if you were to visit, you'd have no place to stand! Photographs of Jupiter show layers of clouds that look like bright and dark stripes. Hold on to your hat! Wind speeds of 224 miles per hour are common on Jupiter. Jupiter's best-known feature is the Great Red Spot, which is a storm that's very similar to a hurricane. It has lasted for centuries! The Great Red Spot is so big - larger than Earth! Jupiter has rings around it, but they're not bright enough for us to see. There are 79 moons around Jupiter. The four largest ones are Io, Europa, Ganymede, and Callisto. Jupiter has a very thick atmosphere comprising a layer of gases surrounding the planet. A day on Jupiter is the same as 10 hours on Earth, making Jupiter the fastest spinning, or rotating, planet in our solar system! Jupiter rotates so fast that the planet bulges around its middle as it spins. One year on Jupiter is the same as almost 12 Earth years, so if you're 10 years old now, you would be only one year old on Jupiter! Jupiter's gravity is so powerful that it attracts many comets and asteroids. This ultimately protects other planets from being hit by them! Several spacecraft have visited or passed by Jupiter, including the Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Cassini, New Horizons, and Juno.