Jupiter is typically the fourth-brightest object in Earth’s sky, trailing only the Sun, the Moon, and Venus. It always shines brighter than the brightest star, Sirius, and at its most brilliant beats Sirius by a factor of four. That’s an impressive feat for an object that lies more than 5 times farther from the Sun than Earth does.
It shines so brightly because it’s so big. Jupiter’s equator spans 88,846 miles (142,984 kilometers), more than 11 times Earth’s diameter. More than 1,000 Earths could fit inside this giant planet. And Jupiter contains 318 times Earth’s mass. In fact, it holds twice as much mass as all the other planets in the solar system combined. Despite its vast size, it spins rapidly, completing one rotation in just under 10 hours.
Learn more about the king of the planets by registering with Astronomy.com and gaining access to the video, "Tour the solar system: Jupiter."