The Sagnac effect, first observed over a century ago, remains central to our understanding of relativistic kinematics and the operational definitions of simultaneity. Fundamentally, this effect arises ...

We've all heard of relativity, but what is it? How does it relate to light and motion? So we've all heard of relativity, right? But... what is relativity? And how does it relate to light? And motion?

A theory developed by Albert Einstein stating that the laws of motion are the same for all inertial (non-accelerating) frames of reference and that the speed of light (in a vacuum) is the same for all ...