A Day on Jupiter Lasts Under 10 Hours

Jupiter has the shortest day in the solar system. It spins once in about 9.9 hours, even though it is 11 times wider than Earth. A point on its equator moves at about 45,000 kilometers per hour (28,000 miles per hour), roughly 27 times faster than a point on Earth’s equator.

The fast spin has visible effects. It stretches Jupiter into a bulge at the equator and drives strong jet streams that pull the clouds into dark belts and bright zones. Jupiter also holds more than twice the mass of all the other planets, moons and small bodies in the solar system combined.