De revolutionibus orbium coelestium

As you know if you've been to Google, today is the 540th anniversary of the birth of Nocolaus Copernicus. He was the Polish astronomer most responsible for the heliocentric view of the universe. That is, the idea that the earth and the planets orbit the sun rather than the sun and the planets orbiting the earth. This motion is demonstrated by an orrery, a mechanical model of the solar system that shows the relative motions of the celestial bodies. V&A Steamworks made a great LEGO Orrery, and you can even see it in action.