Galilean invariance

Galilean invariance, also known as Galilean relativity, is a fundamental principle in classical physics stating that the laws of physics are the same for all observers moving at a constant velocity relative to each other. This means that motion with a constant velocity is undetectable through physical experiments, as all inertial frames of reference are equivalent.12

The Galilean transformations are equations that relate the space and time coordinates between two systems moving at a constant velocity. These transformations are accurate for speeds much lower than the speed of light and assume that space and time are absolute, and that length, time, and mass are independent of the observer's motion. This principle is contrasted with Einstein's special theory of relativity, which posits that the speed of light is constant for all observers and leads to phenomena like space contraction and time dilation. The equivalence principle, a related concept, suggests that gravitational and inertial forces are indistinguishable.3124