The Galeleian Moons are the four largest moons of Jupiter, and they were discovered by Galileo Galilei in 1610 (!). It was the first discovery of a center of motion not apparently centered on the Earth. It was a major point in favor of Copernicus's heliocentric theory of the motions of the planets; Galileo's outspoken support of the Copernican theory got him arrested by the Inquisition. The moons are