Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant and is two and a half times larger than all of the other planets in the Solar System combined, but slightly less than one thousandth the mass of the Sun. Jupiter is the third brightest natural object in the Earth's night sky after the Moon and Venus. It was named after the Roman god Jupiter, the king of the gods.
Jupiter is mostly made of hydrogen, but helium is one-quarter of its mass and one-tenth of its volume. It has a rocky core, but it doesn't have a solid surface. The contraction of Jupiter's interior generates more heat than it receives from the sun. Because of its fast rotation, it has a bulge around the equator. The outer atmosphere is visibly separated into different bands at different latitudes, with and along their boundaries. The Great Red Spot, is a giant storm known to have existed since at least the 17th century when telescopes first saw it.