DrGreg said:
The calculation you make in Lorentz Ether Theory is different to the calculation you make in relativity
Let me develop a little as I try to follow you.
Which calculation do you make in LET? Well, if one believes in an aether, one may also believe that one can make a calculation in the aether frame. If one applies therein the Einstein-Poincaré convention for clock synchronization, one could argue that when the light beams hit the distant clocks in their go-trips, they do it with a sort of "absolute" simultaneity, in the sense that... Difficult to express... Maybe in the sense that if, for example, each light beam has triggered a mechanism that has made a bomb go off, then it is impossible that a signal departs from one clock, which has already exploded, and arrives in time to avoid the explosion of the other clock, even if such signal travels at superluminal speed, even if such signal displaces (I know this is absurd) "instantaneously".
... whereas in SR one would say that a superluminal speed is impossible and so the two events, the two explosions, whose separation is spacelike, are not causally connected, which amounts to the same practical result, i.e. a signal cannot depart from one clock after its explosion and arrive in time to avoid the other's explosion. But if -nevertheless- one day someone found out that superluminal speeds were possible, then... I get lost as to what SR would say in this case. Maybe the answer is nothing, since SR simply rejects that possibility = nothing can travel FTL.
DrGreg said:
(And, in fact, if you choose to use what Lorentz called "local time", you get the same answer in both theories.)
And well in fact, according to LET itself, the hypothesis considered earlier (one makes a calculation in the aether frame and claims to have obtained absolute simultaneity) is impossible to consider in practice, because it is impossible to make any experiment betraying whether one is at rest with the aether or at which speed one moves wrt the aether. Hence in fact one HAS to choose what Lorentz called "local time", which is equivalent to SR's "time without any adjective".
Conclusion: in practice, as it has been mentioned, there is no difference between LET and SR. But that doesn't mean there is no aether, some sort of thing, which is not material, not ponderable matter, pervading space! Who knows? I remember Lorentz said something like this: the great merit of Einstein was making aether fully unnecessary and thus preventing us from wasting time in guessing its mysterious features. But really I think some authors are misleading when they say that SR disproves the aether. It doesn't. It just makes discussions about it superfluous.
Similarly, I also think it is incorrect to say that SR is "preferrable" over LET. The two theories cannot be made to battle against each other because they are situated at different levels. Anything that SR says is also said by LET. It simply happens that LET goes one step further in an attempt to find a causal explanation and makes a hypothesis ("it's all like that because there is an aether"), although it does humbly accept that such hypothesis appears to be unprovable, because everything indicates that such aether would be undetectable. On the other hand, one should also recognize that LET is useful for didactic purposes: it helps to visualize and understand the postulates of SR.
