Scientists Finally Observed Time Crystals—But What the Hell Are They?

The Harvard team’s time crystal (Image: Soonwon Choi)

The Impossible History of Perpetual Motion

On November 12th, 1717, clockmaker and mechanic Johann Bessler placed a 12-foot diameter, strange-looking wheel into a room. With a tender push, he started the contraption rotating, then confidently turned and strolled outside. Guards promptly secured and locked the door behind him. Nobody would be allowed to enter the room for two weeks, lest the machine be tampered with. Perpetual motion machines are finicky gadgets, you see. Read More >>