I seem to remember watching a physicist on TV, possibly Dr. Richard Gott, say that a time machine for traveling to the past might be possible if we could build an infinitely long rotating cylinder. Alternatively, I believe he said, we might be able to do the same thing if the entire universe were rotating. But, he added, we have no evidence that the universe is rotating and it seems that the universe is not rotating.
Rotating? Rotating with respect to WHAT? If there is no other reference point, how could we say whether the universe is rotating or not? More generally, if there were only ONE object in the entire cosmos, would we even be able to tell whether it was rotating or not? Or, for that matter, how could we even DEFINE rotation in the absence of another reference body?
This brings up the related question, is there such a thing as “ABSOLUTE ZERO ROTATION,” analogous to an inertial platform which was not moving at all along a linear path, and was absolutely stationary, at zero velocity in absolute terms? Einstein (And probably Newton too) said there is no favored inertial reference platform which in absolute terms has zero velocity. I tend to agree myself. Would not the same be true of rotation? But then, on the other hand, what about our intuition that a rotating body experiences centrifugal force, and that if it rotates rapidly enough it will fall apart? Would this intuition be violated if there was no second body for reference? I think these questions are beyond my present ability to answer. I simply do not know how to answer them. I wonder if there are any physicists, cosmologists or philosophers who DO know how to answer them. Neither answer seems satisfactory. What do you think?
withthesongstillinsidethem 