The unique Saturn's walnut-shaped moon, Iapetus, got its nutty shape from a super-fast spin that was frozen into place early in the solar system's formation. Unlike any other moon in the solar system, the 4.564 billion-year-old Iapetus is the same shape today as it was when it was just a few hundred million years old. It's a well-preserved relic from the time when the solar system was young. The distinctive mountain ridge along its equator is 808 miles (1,300 kilometers) long and 12 miles (19 kilometers) high. Sources: Space, Skyandtelescope & Sciencemode
