The fastest-moving planet in the solar system is Mercury. The planet whizzes around the sun at an orbital velocity of 1.6 times that of Earth's orbital velocity. This amounts to 107,700 miles per hour.
Named for the speedy messenger of the gods, Mercury lives up to its name. Mercury also has the closest orbit to the sun; the planet lies only about 36 million miles away from the sun. The speed at which Mercury makes its orbit gives it an orbital period of only about 88 Earth days. Mercury's year, or the time it takes Mercury to make one complete revolution around the sun, is less than one-quarter of the time Earth takes to make its orbit around the sun; therefore, a year on Earth is four times that of a year on Mercury.