I value thought experiments as useful tools to understand how things work. Thought experiments, also known as idealized experiments, have a surprisingly noble history. For example, Albert Einstein used the thought experiment of a constantly accelerating elevator with a pinhole in the side through which a light beam could shine to illustrate the effect of gravity on light.
In the gravity-effect-on-light thought experiment, you have the ability to watch a light beam as it moves from the pinhole in the side of the elevator, across the elevator that is constantly accelerating perpendicular to the original path of the light beam. With that ability, if gravity affects light, you would then see the light beam bend as it moves across from the pinhole to the other side of the elevator.
The wavefront of the light beam in a non-moving elevator would move in a straight line across the elevator. If the elevator […]
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