Re: FTL transmission?

From: Brian Atkins (
Date: Tue May 30 2000 - 21:47:52 MDT

Eugene Leitl wrote:
> Brian Atkins writes:
> > Can anyone clear this up for me: if they have light signals emitted from
> > this setup on the far end even before the light on the near end has fully
> > entered the chamber, what is preventing me from constructing a very long
> > chamber of this sort from here to Alpha Centauri and then conducting
> > transmissions through it with no delay whatsoever?
> Because it doesn't scale (quantum entanglement does though), and you
> still need a relativistic channel to distinguish the signal from
> noise.

I still don't get it, what noise? If I'm sitting at the far end of this
thing with a photodetector then it should only be going off when photons
hit it as they exit the far end. How will there be noise? And what is
preventing me from scaling it up and spitting out a continuous stream of
photon packets?

> Since superluminal information transfer is equivalent to time travel
> (and hence paradoxes etc.), don't expect true ansible real soon.

I am confused here too. I don't see how this would be time travel.
Isn't there a distinction between information flow (images of events...
say pictures we see in a telescope of a supernova blowing up) and the
actual event generating the information? So what if I can transmit
a digital pic of the supernova blowing up to someone far away before
they can see it in their telescope- that isn't really time travel as
far as I can see. The supernova has still already blown up whether or
not they can see it yet. Light does not create time. Movements of
atoms creates the illusion of time.

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