REVIVING GRAVITY'S AETHER IN EINSTEIN'S UNIVERSE
sk any good student of freshman physics and, happily quoting their textbooks, they will tell you that gravity is the weakest force of nature. After all, when you lift a pen, the electromagnetic dipoles of the molecules in your hand can easily counteract the gravitational pull from the entire planet Earth. It may thus come as a surprise that throughout history, understanding gravity has been one of the strongest drivers of breakthroughs in theoretical physics, and yet it still remains its deepest mystery. After Newton’s discovery of universal laws of gravity and mechanics, physicists and philosophers often wondered how gravitational forces could act over large distances, while other forces of nature only act in extreme proximity. In fact, this was one of Einstein’s philosophical motivations to introduce metric, or space-time geometry, as a medium that mediates gravitational forces, as “action at a distance” cannot be physical. But we are jumping ahead of ourselves!