"Mass tells space-time how to curve, and space-time tells mass how to move."John Wheeler is commenting on a result of Einstein's general theory of relativity, stating how space-time can bend. Gravitational force can be explained by the warp that a massive object causes on the space around it. Other objects coming near this massive object are forced to follow a course dictated by the warp, their paths being distorted. This is often compared to placing a large ball, like a bowling ball, on a stretched rubber surface. The ball causes a deformation in the surface, and if a smaller ball, like a marble, is dropped onto the surface, it will follow a path dictated by the warped surface.
 |
| A two dimensional projection of a three dimensional analogy of space-time curved around Earth. Image: Johnstone, via Wikipedia |
