Galileo's book. Title page of Sidereus nuncius (The Starry Messenger, 1610) by Galileo Galilei (1564-1642), detailing discoveries made with his newly invented telescope. The discoveries included sunspots, faint stars of the Milky Way, four satellites of Jupiter, the phases of Venus and mountains on the Moon. He achieved a great deal of fame through the book. Galileo also studied gravity, showing that heavy and light objects fall at the same rate. His support for the Copernican theory that the Sun is at the centre of the solar system led to persecution by the Inquisition.