Special Relativity
Formulated by Albert Einstein in 1905, special relativity changes our understanding of space and time for objects moving at constant high speeds. Its two core postulates are:
- The laws of physics are the same in all inertial frames.
- The speed of light in vacuum is constant for all observers, regardless of the motion of the source.
Key consequences include time dilation, length contraction, and the equivalence of mass and energy (E=mc²).
General Relativity
Published in 1915, general relativity extends the principles of special relativity to include acceleration and gravity. It describes gravity not as a force but as the curvature of spacetime caused by mass and energy.
- Mass tells spacetime how to curve.
- Curved spacetime tells mass how to move.
Phenomena such as gravitational time dilation, black holes, and the bending of light by massive objects arise from this theory.