One hundred years ago, Albert Einstein completed his general theory of relativity, which explains how the gravitational force works. This made Einstein an international celebrity during his time, and the theory is widely recognized as one of the greatest achievements in the history of science.
Broadly speaking, by generalizing his special theory of relativity to account for gravity and acceleration, Einstein found that gravity could be explained as physical objects warping the fabric of space and time. In other words, the fabric of space-time is the medium through which the force of gravity is transmitted.
One way to visualize this is by thinking of space as a rubber sheet. If you push a marble across the sheet, it will roll straight from one side to the other. But if you put a bowling ball in the center of the sheet, it will bend the fabric around it. And if you then push a marble across, it will roll towards the bowling ball, similarly to how Earth orbits the sun.
Walter Isaacson, author of Einstein: His Life and Universe, explains how Einstein came to this groundbreaking discovery and completely revolutionized our understanding of gravity and the fabric of the cosmos.
Fusion’s original Relatively Speaking series celebrates the 100th anniversary of Albert Einstein’s general theory of relativity.