Einstein's Theory

Einstein's theory of relativity includes two main ideas: special and general relativity. Special relativity shows that the laws of physics are the same for all observers moving at constant speeds, and that the speed of light is always constant. This leads to surprising effects like time slowing down for objects moving close to light speed. General relativity describes gravity not as a force but as the curvature of spacetime caused by mass and energy. Massive objects like stars and planets bend spacetime, and this curvature guides the motion of other objects, explaining how gravity works on a cosmic scale.