The principle of relativity

The principle of relativity, originally formulated by Albert Einstein, states that the laws of physics are the same for all observers, regardless of their relative motion. This means that whether you are standing still or moving at a constant speed, the fundamental principles governing physical phenomena—like gravity and motion—remain unchanged. It also introduces the idea that there is no absolute frame of reference; rather, measurements of time and space can vary depending on the observer's state of motion. This principle has profound implications for our understanding of the universe, especially in the fields of physics and cosmology.