Frame of Reference

In physics your perspective is called your frame of reference, a concept central to Einstein's theory of relativity. Here's an example from everyday life: If you are in a moving train, your reference frame is inside the train, which appears at rest to you, with objects inside the train not moving relative to one another, or to yourself. However, to someone outside the train looking in, you and all the objects in the train are moving at great speed, as seen from their different frame of reference, which is stationary to them. In fact, everything but the speed of light—even time appears different in different frames of reference.