The Special and the General Theory of Relativity

Einstein's Special Theory of Relativity (1905) shows that the laws of physics are the same for all observers moving at constant speeds, and that the speed of light is constant. This leads to effects like time dilation and length contraction for fast-moving objects. The General Theory of Relativity (1915) expands this idea, describing gravity not as a force but as the curvature of spacetime caused by mass and energy. Massive objects like stars bend spacetime, and this curvature guides the motion of planets and light. Together, these theories revolutionized our understanding of space, time, and gravity.