One hundred years ago today at the Prussian Academy of Sciences, Albert Einstein gave the first in a series of lectures that rewrote Newton’s laws of gravity and changed the world. In The Hunt For Vulcan: … And How Albert Einstein Destroyed A Planet, Discovered Relativity, And Deciphered The Universe, Tom Levenson reveals how this revolution could not have happened without disproving an obscure astronomical calculation.

According to Newton, Mercury’s wobble was caused by the gravitational pull of some other planet. Enter Vulcan—the so-called “other” planet—first observed in 1859; confirmed by the greatest astronomer of the day, Urbain Le Verrier; and hailed by The New York Times as one of the great discoveries of the century. Trouble was,