Asteroids are extremely small planets moving around the sun. Most of them - but not all - travel in a path between Mars and Jupiter. This is known as the asteroid belt. Now the asteroids, especially the largest of them all, Ceres, are being closely studied because they could be used as space stations in the future. The NASA spaceship 'Galileo' has sent back many pictures of the asteroid belt. Among these are the first pictures of an asteroid moon. The moon was found circling the asteroid Ida. It has been named Dactyl, which means 'Finger'.