Alpha Centauri, a system of three stars, one of whose membersProxima Centauriis the star nearest the sun. Proxima can be seen only with a telescope; the other two stars appear as a single, very bright star to the unaided eye. Alpha Centauri is slightly more than four light-years from the sun. It is in the constellation Centaurus.
The moon is often the largest object in the sky outside of the sun. What is the moon made of, how did it form -- and why do people blame it for their strange behavior?
The changing phases of the moon have given us an enduring curiosity about the dark side of the moon. But is there really a dark side of the moon? What would we see there?