One of Kepler’s admirers was Galileo Galilei, the first astronomer to use a telescope, and the last to be persecuted by the Church for suggesting that the Earth traveled around the Sun. Among Galileo’s many discoveries were the craters of the Moon, the phases of Venus, some of the moons of Jupiter, and sunspots.

     Everything he saw convinced him that Aristarchus, Copernicus, and Kepler were right in suggesting that the Earth moved around the Sun. But in 1616 Galileo was ordered by the Church in Rome to stop supporting what had become known as the Copernican system. He was forced to publicly recant his theories.

     Galileo immediately began work on a book called "Dialogue of the Two Chief World Systems", in which the whole question was fairly discussed from the two opposing points of view. He obtained clearance from Rome to publish the book, but was summoned to answer on charges of heresy when the book appeared in print, even though the Church censors had approved it.

     At his trial he was forced to make another public recantation. On his knees before the Church, Galileo read a statement proclaiming that he was ready to "curse, abjure, and detest" the theory that the Earth moved around the Sun. Had he not done this, he would have been burned alive at the stake. He was ordered to spend the rest of his life under house arrest, and allowed no visitors or outside contact other than the servants who cared for him.

     When Galileo died in 1642, the Pope forbade the erection of a monument over his tomb. But within 50 years, the central-Earth theory completely crumbled.