Mars has two small moons named Phobos and Deimos. They are irregularly shaped and much smaller than Earth's moon, with Phobos being about 22 kilometers wide and Deimos around 12 kilometers wide. Both moons are thought to be captured asteroids from the Asteroid Belt. Phobos orbits Mars very closely, completing a full orbit in just about 7.6 hours, while Deimos takes about 30.3 hours to orbit the planet. Their surfaces are covered in craters and dust, and they are believed to be composed of rock and ice. Scientists continue to study these moons to learn more about their origins and the history of the Solar System.