Jupiter is the heaviest planet in our solar system: Mass: Jupiter is more than 300 times the mass of Earth. It has the largest mass and volume of any planet in our solar system. Size: Jupiter’s diameter is about 11 times that of Earth. Composition: Jupiter has the same ingredients as a star, but it didn’t grow massive enough to ignite. Rotation: Jupiter has the shortest day of all the planets, spinning on its axis once every 9 hours, 55 minutes, and 29.69 seconds. Moons: Jupiter has the highest number of known natural satellites, with 79. Gravitational pull: Jupiter has the strongest gravitational pull of all the planets