The Pleiades star cluster (M45) has caught the attention of sky-gazers since ancient times. Under normal conditions, most observers can see six Pleiads without optical aid.
Chris Schur
Four centuries ago, the Italian astronomer Galileo Galilei opened up the universe with his telescope. Among his discoveries were mountains and craters on the Moon, four bright satellites orbiting Jupiter, and the changing phases of Venus — all of which contradicted the common belief of a perfect Earth-centered universe.
