Why does earth only have one moon, while other planets have many? Jupiter alone has nearly 40 moons! Learn more on this Moment of Science.
Ever wonder what it's like on other planets? On this Moment of Science, find out what it's like on Mercury.
Have astronomers discovered a new planet? Find out on this Moment of Science.
How fast anything spins is partly determined by how its weight is distributed. The closer an object’s weight is to its axis of rotation, the faster it spins. To picture this, imagine an ice skater doing a pirouette. When her arms are extended, she spins slowly.