(urth) Sundial with "multitudinous faces"?

[Dan'l Danehy-Oakes]

On Thu, May 12, 2011 at 10:59 AM, James Wynn <crushtv at gmail.com> wrote:

> I would think you could. Any regular tick-tock could analogize a time using
> a different synch. It would be incredibly complex though since a day
> somewhere else would be represented by more or less than a single cycle of
> the sun.

Well, that was my point...

> However, doesn't Relativity eliminate the meaning of synchronous time for
> locations separated by many lightyears? I'm not an expert on this but it
> seems I read something that implied that. For example, traveling in a
> worm-hole (such the ones in the Stargate franchise) is actually Time-travel
> as well.

If there's FTL travel then some aspect of relativity is untrue.

But: taking relativity at face value, there is no such thing as "time
travel" -- or for that matter "space travel." There is only spacetime
travel through a four-dimensional manifold. To move to another point
in space is to move to another point in spacetime, and so to travel in
spacetime. To move to another point in time while standing still, as
one does at a rate of one second per second, is also to move to
another point in spacetime. The problem is _why_ time is different and
can't be navigated at-will the way the other three dimensions can, and
no satisfactory answer to that has yet been proposed.

-- 
Dan'l Danehy-Oakes