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tags: #physics #relativity

The Principle of Relativity is the foundational postulate of Einstein's theory of Special Relativity. It is composed of two main ideas:

1. The laws of physics are the same for all observers in uniform motion (i.e., not accelerating). This means that the outcome of any physics experiment will be the same whether you are in a stationary lab or a spaceship moving at a constant velocity. There is no privileged "rest frame" in the universe.
2. The speed of light in a vacuum is the same for all observers, regardless of their motion or the motion of the light source. This was the radical insight supported by the Michelson-Morley Experiment.

These two principles, when taken together, have profound consequences that shatter our classical intuitions. If the speed of light is constant for everyone, then something else must change to compensate for relative motion. That "something else" is space and time itself.

This leads directly to the strange and experimentally verified phenomena of Time Dilation and Length Contraction.

Reference

Coursera, "Question Reality: Matter"