Ehrenfest Paradox
Steve Landsburg, an economist/mathematician who fancies himself an expert on relativity (he has written a book on GR) poses the following problem: . A circular train (front of the locomotive attached to the rear of the caboose) sits on a circular track. At some point, the train accelerates and starts traveling around the track. Because the train is moving, I (an observer stationary relative to the track) should see it shrink. But the track doesn’t shrink. So the train can’t stay on the track, and gets pulled inward, ending up inside the track. On the other hand, the passengers say the track has shrunk, so they should expect to get pushed outside the track. How can everyone be right? This is a famous puzzle known as The Ehrenfest Paradox , but I think that Landsburg's "solution" is less than adequate - not really even correct. Any comments? UPDATE: Here is what I came up with. It has one major flaw that I really should try to fix: I really like this problem and had sever...