General theory of Relativity

3

Einstein’s Field Equations

3.1 INTRODUCTION

Since special relativity requires all objects and particles to be limited by the speed of light, all forces and interactions must travel at or below the speed of light. Newton’s gravitational theory is in contradiction with this principle because it states that the gravitational force acts instantaneously. Einstein spent many years attempting to create a gravitational theory that does not require forces to act faster than light.

Rather than explaining gravity as a force that acts¹ instantly as Newton did, he hypothesized that gravity is simply a consequence of space–time curvature. In order to understand space–time curvature, picture a two-dimensional surface. A ball, representing the sun, lies on ...