Jupiter is the largest planet in the solar system and outweighs all the others combined.

The longer version

Jupiter's bulk comes from its formation in the cold outer solar system, where ices could condense and add solid material to a growing core. Once that core became massive enough, it swept up hydrogen and helium from the surrounding nebula faster than the terrestrial planets ever could.

Its mass is so great that it shapes the architecture of the whole system, nudging asteroid orbits and holding a large family of moons. Unlike rocky worlds, Jupiter has no solid surface; the visible clouds are simply the top of a deep atmosphere that gradually thickens with depth. The planet also spins remarkably fast, turning in a matter of hours.

Where this entry sits

The night sky looks calm, yet almost everything up there is moving, burning, or slowly changing. These facts cover planets, stars, the Moon, gravity, black holes, comets, and the story of how people began exploring beyond Earth. The full list sits on the Space and Sky page, where every entry is listed in order.