🚀 go-pugleaf

In article <3288d...@cfanews.harvard.edu>,
	gir...@skyron.harvard.edu (John Girash) writes:
   Danny Bersch (ber...@sst.sps.mot.com) wrote:
   : sh...@one.net (Scott Hess) writes:

   : Perhaps more correctly stated, "The speed of light in a vacuum,
   : c, *appears to be* a property of our universe, like pi or e.
   : Current popular theory predicts that one _cannot_ go faster than
   : the speed of light while remaining in our universe."

   Oh for Pete's sake, the values of pi and e have nothing to do with
   "which" universe you're in.  They're mathematical concepts, that'll
   be the same anywhere that 1+1=2.  They are NOT properties of our
   (or any other) universe!

I'm not certain what the difference would be.  Numbers like 1 and 2
are simply conveninent labels for certain concepts.  pi is a specific
value derived from observation, for instance of the relationship of a
circle's diameter to its circumfrence.  _Any_ mathematical system into
which our definitions for numbers can be translated can have an
expansion for pi translated, too.  That doesn't imply that in the
universe that mathematical system exists, a circle's circumfrence is
pi times its radius, though.

To a certain extent, c is just a mathematical concept, too.  Putting a
measure of velocity to c doesn't really mean much, because velocity
itself becomes a strange thing when you approach c.  c measures the
maximum velocity in our universe, and though you can blithely say
things like "2*c", such a number currently has about the same value as
sqrt(-1), or extra spatial dimensions.  [Which is to say, you can use
it in equations but you can't grab it or experience it.]

   : #]This isn't really a matter of opinion.  <SNIP>
   : #]I can just prove that YOU CAN'T GET THERE FROM HERE!  
   : 
   : Can you *really* prove it?  If so, let's send all those erudite
   : physics weenies home.  The job is done.  Or is it that what you
   : can do is to derive the current theory and spread your
   : derivations (complete with all the required assumptions) before
   : us for our perusal?  Science seeks to understand and predict, and
   : to that end, we create models (theories) that we believe will let
   : us extrapolate from what we know to what we would like to
   : understand.  As such, our theories are molded as much by that
   : which we would like to understand as by the nature of the
   : physical universe.  Newton was exactly correct, for his day, as
   : was Ptolemy.  Both modeled what was known and predicted what was
   : needed.  *Proof*, we must remember, has a temporal aspect to it.

Stop and think about the range of testing which have been given to
Einstein's theories versus those of Newton.  From a Newtonian
standpoint, the set of possible velocities is congruent with the set
of non-negative real numbers.  Until the last hundred years, only the
lowest end of that set could be tested.

Einstein's equations provide for an upper bound to velocity, and the
equations have been tested quite close to the limits of that boundary.
The equations work from 0 right up to very close to c.  It's not a
matter of discovering a whole new realm of velocities which the theory
doesn't handle.

[Of course, as I noted above, just as you can map any subset of real
numbers onto the entire set, c in some sense is an open-ended guage of
speed, also.  Commonly we think of velocity as the time it takes to
get from one point to another.  For speeds where Newton works, it is
equivalent to define an object's velocity in terms of accelerations
which are applied to the object.  If that definition is used, c
effectively becomes infinity, where it belongs.  Another way of saying
this is that it only makes sense to give c a value when you are an
observer - when you are the moving object, you can treat yourself as
being at rest!]

   You can say that Newton was "exactly correct for his day"(*) but
   you cannot say he was _complete_.  From this point of view,
   relativity doesn't invalidate Newton, it generalises it, _adding_
   more physics.  But to allow for faster- than-light travel, you have
   to _remove_ some physics from relativity, a a completely different
   situation.  (And to be complete, even "wormholes" don't allow v >
   c, they just provide a "shortcut" route to an otherwise distant
   location).

Exactly!
--
scott hess <sh...@one.net>     (606) 578-0412      http://w3.one.net/~shess/
<I plan to become so famous that people buy tapes of me reading source code>