Today virtually every child grows up learning that the earth orbits the sun. But four centuries ago, the idea of a heliocentric solar system was so controversial that the Catholic Church classified it as a heresy, and warned the Italian astronomer Galileo Galilei to abandon it. The Google homepage pays homage today to Nicolaus Copernicus, the pioneering astronomer. Legend has it that Nicolaus Copernicus and the church were at odds over his development of the heliocentric theory, a principle that disputed the widely held belief that Earth was the center of the universe.