We’ve had more than 400 years to get used to the idea, but it’s still a little unsettling. Anyone can plainly see that the Sun and stars rise in the east, sweep across the sky and set in the west; the Earth feels stable and stationary. When Copernicus proposed that the Earth and other planets instead orbit the Sun, his contemporaries found his massive logical leap “patently absurd,” says Owen Gingerich of the Harvard-Smithsonian Center for Astrophysics. “It would take several generations to sink in. Very few scholars saw it as a real description of the universe.”
Galileo got more grief for the idea than Copernicus did. He used a telescope to provide evidence for the heliocentric theory, and some of his contemporaries were so disturbed by what the new invention revealed—craters on a supposedly perfectly spherical moon, other moons circling Jupiter—that they refused to look through the device. More dangerous than defying common sense, though, was Galileo’s defiance of the Catholic Church. Scripture said that the Sun revolved around the Earth, and the Holy Office of the Inquisition found Galileo guilty of heresy for saying otherwise.