From: hinson@maxwell.physics.purdue.edu (Jason W. Hinson)
Newsgroups: rec.arts.startrek.tech
Subject: FTL travel/communication >> It's is "sci fictionaly" possible
Date: 16 Aug 92 20:34:59 GMT
Organization: Purdue University Physics Department

I am glad to report that I beleive I have found a way to travel faster
than light could (in a science fictional way of course) without violating
causality (and without violating what we know to be true today).

The following is a message I posted to sci.physics in order to test
my idea.  I have had two people respond (one of which said that as a 
"special" frame of reference, one could use the cosmic background radiation).
The other response I have included after the copy of my message.  It
indicates that my idea is not an impossibility.  If you are interested
in being able to "believe" in science fiction that allows FTL travel, then
please read on:


From me:
The following is a science fictional excursion discussing the possiblity
of space-time having a preferred frame of reference without violating
relativity.  My request is that someone tell me how we know that it cannot
be true.
 
Perhaps space-time is something like what was beleived to be the ether.
However, this medium of wave propagation would have the strange property
that an electromagnetic wave moving through it would be seen by all
inertial observers as having a speed c. This would take into account
at least the effects of special relativity.
 
If the above were not an impossiblity, then space time could have a
particular fram of reference.  Then one could fictionally warp that
space time to send a message/traveler to another point in space faster
than light could reach that point.  Then, the message/traveler would
have the time/space line of the preferred reference frame no matter who
is observing the message/traveler. So there would be no problem with
causality violations (I blieve).
 
That last comment prompts another question:  Is it true (as I think it
is) that if there were some prefered reference frame, then we could
travel from A to B faster than light without violating causality?
For example, assume we can send messages faster than light; however
everyone (and everything) agrees not to send or recieve such messages
unless he/she/it is stationary relative to.. say... the Earth.
Could there still be a violation of causality?
(to make it easier, assume that we could send the message instantaniously;
however, since no one would send or recieve the messages unless he is
not moving relative to the earth, instantaniously would, in effect, always
mean "in the reference frame of Earth.")
 
Thanks for any input



Response from: mcirvin@husc8.harvard.edu (Mcirvin)

We do not know that this cannot be true.  Your statement that there would
be no problem with causality is correct, since spacelike communication-->
causality violation depends on the ability to change the spacelike
surface (or in SR, the inertial frame) in which the communication is
instantaneous, and this proposal explicitly removes the possibility.
 
It does "violate relativity" in the sense that it denies one of the
basic postulates, namely that *all* the laws of physics are the same
in all inertial frames.  It doesn't completely tear it apart, though;
it just turns it into a theory of some special subset of physics,
including all physics currently known.  It doesn't violate causality.
 
Rather than just say that the "ether" has the property that c is the
same in all frames, I'd say that the "ether" is only an ether for
these extra, instantaneous interactions, and has no relevance to
anything else.
 
This is, as others and I have pointed out before, a nice self-consistent
way to put faster-than-light travel into science fiction.  It isn't
at odds with any data and doesn't introduce the possibility of time
travel into the past.  All one needs to assume is some nonlocal
phenomenon which disobeys relativity in this way.
 
The other side of the coin is that there is absolutely no evidence for
any such thing, and no need to introduce it other than that it might
be nice to have.  Relativistic covariance has turned out to be an
extraordinarily successful framework in which to construct a model
of physics, and to most of us, at least, there seems to be no reason
to abandon it.  But nothing currently known from experiment rules out
extra physics of the sort you describe.
 
--
Matt McIrvin, Cambridge, Massachusetts, USA

******************************************************************

There you have it:

In short, perhaps there is some sort of medium (perhaps space-time itself)
which has one particular frame of reference, and which can be warped to
allow FTL travel.  As long as all such travelers have the space-time 
frame of that special medium (reguardless of speed), then there is no
problem with causality.


Comments?
-Jay 
Newsgroups: rec.arts.startrek.tech