Einstein's classic thought experiment involves sitting on a train travelling at the speed of light. If you hold a mirror in front of your face, will you see your reflection in a mirror?

Now consider Einstein's previous assertion that time and space are relative. If motion can affect time and space (like with the train experiment) and gravity and acceleration behave the same ...

But on the train, you are closer to the bolt ... This thought experiment is a well-known variation of Einstein's light clock thought experiment, which has to do with the passage of time.