Which physicist formulated the special and general theories of relativity?

Albert Einstein formulated the special and general theories of relativity. Special relativity was published in 1905, while general relativity was completed in 1915 and published in 1916.

Special relativity describes space and time for observers moving at constant speeds, especially near the speed of light. Its foundations include the constancy of light’s speed and the idea that the laws of physics are the same in all inertial reference frames. It led to effects such as time dilation, length contraction, and mass–energy equivalence, summarized by E = mc².

General relativity extended these ideas to gravity. Einstein proposed that massive objects curve spacetime, and that this curvature guides the motion of planets, light, and other matter. Isaac Newton’s laws remain excellent approximations in ordinary conditions, but general relativity explains phenomena such as Mercury’s orbital precession, gravitational lensing, and black holes.

A common mix-up is crediting only special relativity to Einstein while treating general relativity as a separate theory by another scientist. Both are Einstein’s theories, although many researchers contributed mathematical and experimental work around them.