Jupiter is the largest planet in the solar system. Jupiter is so big that all the other planets in the solar system could fit inside it. More than 1,300 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 night sky. Venus is brighter. The planet is named after another Jupiter. He was the king of the gods in old Roman stories.
The planet Jupiter is not a solid like Earth is. Jupiter is made of gases. It 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.