Originally posted by ivan2908
I was always wondered something which is pretty stupid but interesting. Theoretically if you connect Earth and moon with some indestructible rope (we are about 384000 km far away from the moon) and astronaut is holding one end of the rope on the moon, Earthling the second end... So lets say that man from earth pull the rope (ignore practical problems like h he would achieve that with most primitive device imaginable...
Any hole in my assumption ??
When you pull on a rope, you pull *directly* only on the portion you are in contact with. That portion, in turn, pulls on the next portion, and so forth, until finally the object at the other end is pulled. In other words, force must be transmitted, molecule by molecule, down the length of the rope. I think also that for this reason the postulation of an absolutely inflexible rope (or anything else) is an erroneous premise. All of this, of course, represents conventional assumptions which I don't agree with, but you were asking the question within a conventional framework, and so I have answered it.
That said, special relativity is nonsense. It fails to apply the principle of "the relativity of simultaneity" to the process of clock synchronization itself: if it did apply it, each observer would have to conclude that all other observers (in uniform relative motion) mis-synchronized their clocks because those observers made an erroneous assumption at the time they did so: namely, that their clocks were stationary.
For example, observers A and B are in uniform relative motion. Each observer has a pair of clocks, separated by some arbitrary distance, which are part of his own system of reference. In order to make measurements, each observer must synchronize his own pair of clocks by sending a light signal between them. But the process is not wholly empirical: it relies on an assumption by each observer about the distance travelled by the light signal. Each observer assumes that he himself is at rest when determining the distance that his light signal travelled. Consequently, since these observers are in uniform relative motion, A assumes that B is moving, and vice-versa. This means that A should assume that B, in synchronizing B's clocks, has erred by using the wrong distance, in his calculations, for the distance travelled by B's light signal between B's clocks. If A does this, applying the principle of the relativity of simultaneity to B's clock synchronization (as to all other physical processes), the quantitative discrepancies (as of dilations of space and time) disappear from the theory. Instead, in Special Relativity the process of clock synchronization possesses an absolute character, unlike any other physical process in the theory: A assumes that B has properly synchronized his clocks even though A's own observations tell him that the distance travelled by B's light signal, when B synchronized his clocks, was different than the distance which B used in his own calculations.
Edit: Of course, when I talk about "A's own observations" I really mean his observations coupled with his assumption that B is moving.
25 Feb '08 17:051 edit
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