Special Relativity is Albert Einstein's groundbreaking theory from 1905 that fundamentally changed how we understand space, time, and motion. This theory applies to objects moving at constant speeds, especially when approaching the speed of light.
Special Relativity is built on two fundamental principles. First, the principle of relativity states that physical laws are identical in all inertial reference frames - there's no preferred frame of reference. Second, the speed of light in vacuum is constant for all observers, regardless of their motion.
Special Relativity predicts two remarkable effects. Time dilation means that moving clocks run slower relative to stationary ones. Length contraction means that objects in motion appear shorter along their direction of travel. Both effects become significant only at very high speeds approaching the speed of light.
Einstein's most famous equation, E equals m c squared, reveals that mass and energy are interchangeable. A small amount of mass can be converted into an enormous amount of energy, since c squared is a very large number. This principle explains nuclear reactions and powers the sun.
Special Relativity has profound modern applications. GPS satellites must account for time dilation to maintain accuracy. It's essential in particle physics, nuclear power, and medical imaging. This theory revolutionized our understanding by unifying space and time, laying the foundation for modern cosmology and leading to Einstein's General Relativity.