If light travels in a straight line then why do shadows bend?

Light travels in a straight line in a vacuum. It certainly does not travel in a straight line when confronted with a mirror, for example, and reflection off of a mirror is not the only way that matter interacts with light. read more

The precise statement should be that light in free space moves in straight lines and constant velocity wrt inertial reference frames. It does not move in straight lines or constant velocity in accelerating reference frames or in non homogeneous media. The fact that the speed of light is independent of the observer's velocity is a relativistic effect. read more

It does not move in straight lines or constant velocity in accelerating reference frames or in non homogeneous media. The fact that the speed of light is independent of the observer's velocity is a relativistic effect. Formally it is a postulate of special relativity. In general relativity light follows geodesics wrt the spacetime metric. read more

Because light travels in straight lines. (unless some form of meta-material is present in its path). read more