The Principle of Relativity (book)

The Principle of Relativity, as explained in Albert Einstein's book, states that the laws of physics are the same for all observers who are moving at constant velocities relative to each other. This means no experiment can distinguish whether you're stationary or moving at a steady speed without looking outside. It challenges the idea of absolute motion, implying that concepts like time and space are relative and depend on the observer’s frame of reference. This foundational idea revolutionized our understanding of the universe, leading to the development of Einstein’s theories of special and general relativity.