Time travel (209)

103 Name: Anonymous Scientist : 2007-11-30 15:57 ID:a4NPZkeb

OK, point on the speed of a tube of ball bearings 10 light second long. It would take approx. 139 hours, assuming the ball bearings are perfectly aligned and made of steel, for the "information" that the first ball bearing moved to reach the last one.

I know the fact it moves at the speed of sound has already been pointed out, I just thought I'd throw a number next to it.

There are two types forces through a median - longitudinal vibrations and transverse vibrations. Since we are compressing the metal bearings, we want longitudinal vibrations. The speed of longitudinal vibrations through steel is about 6000 m/s.

Also, since there seems to have been some misunderstanding...
as long as the ball bearings are all aligned correctly, they behave EXACTLY like a single unit, except for the last one which will pop out.

Interestingly, a cylinder that is infinitely massive would be unable to be compressed, and it seems that the information of a force should be instantaneous through it, right? Not that it would matter, since it could obviously not exist, but still, it's a curious question.

Also, another question. Since light moves at the speed of light (or very, very close to it), from the perspective of the light (if you can imagine such a thing), would the light exist along all of its paths at once, if we ignore any time it hits a medium that slows it down?

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