Special Relativity
Albert Einstein's 1905 theory describing the physical behavior of space and time for observers moving in uniform non-accelerated inertial frames.
Governing formula
E² = (p c)² + (m₀ c²)², γ = 1 / √(1 - v²/c²)
SI unit
Theoretical Framework
In depth
Rests on two fundamental postulates: the laws of physics are identical in all inertial reference frames, and the speed of light in vacuum c is a universal constant for all observers regardless of motion. Predicts time dilation, length contraction, and mass-energy equivalence.
Examples in the real world
Cosmic ray muons reaching Earth's surface due to relativistic time dilation expanding their apparent lifetime.