For thousands of years, people pictured the sky as a giant dome surrounding the Earth. The stars were thought to be fixed to this dome, which slowly turned above us, much like the motion of the Sun, the Moon and the planets. This book tells the story of the scientific revolution that changed that picture forever—the moment humanity realized that the motions we see in the sky are only apparent motions, created by the Earth spinning on its axis and traveling around the Sun. The “celestial dome,” it turned out, was an illusion. It is the Earth—and the heavens—that move.
This revolution began with Nicolaus Copernicus’s book On the Revolutions of the Heavenly Spheres, published in 1543, just as the author was nearing the end of his life. The bold ideas in that book sent shockwaves through the scientific world and helped lay the foundations of modern physics. They also transformed the way people thought about nature—and about humanity’s place in the universe. This book follows the dramatic story of the Copernican Revolution and the long struggle to convince the world of its truth, from Galileo’s telescopic discoveries—made with a telescope he built himself—to the fierce scientific and religious debates that followed.
The Copernican Revolution opened the door to an even bigger idea: The universe is vast, stretching far beyond our solar system. The “fixed stars,” we learned, are actually distant suns, so far away that they appear as tiny points of light. From there, it was only natural to wonder whether some of those stars might have planets of their own. At the end of the twentieth century—more than 400 years after Copernicus—astronomers finally discovered that planets are everywhere, orbiting stars across the galaxy. And who knows—perhaps some of those distant worlds may even host life.