Re: definition of a clock in relativity theory

From: suzysewnshow (suzysewnshow_at_yahoo.com.au)
Date: 08/30/04 

Date: 30 Aug 2004 07:20:26 -0700

Eric Baird <eric_baird@compuserve.com> wrote in message news:<u3n4j0l7h8aeqri5g72eemphjbek1qr2rn@4ax.com>...
> On 26 Aug 2004 06:32:33 -0700, suzysewnshow@yahoo.com.au
> (suzysewnshow) wrote:
>
> >> And if the strong-gravity observer can see the image of the clock to
> >> be apparently running "fast", and running at that accelerated rate for
> >> an arbitrarily long time-period, we seem to run out of explanations
> >> for how this situation could be sustainable in real life, unless the
> >> "natural" rates of clocks in the strong-gravity and weak-gravity
> >> regions is different by the same amount as the observational mismatch
> >> in apparent clockrates that we just worked out.
> >
> >Indeed!
> >If the pitcher throws 1 ball per second for 1 hour and the catcher
> >catches more than one ball per second, higher frequency due to the
> >"over the plate blue shift", then at the end of the hour the catcher
> >should have more balls at his feet than the pitcher ever threw. I
> >suppose it has something to do with trusting a scholar with a slide
> >rule before he masters the abbacus or the bribery of umpires. I am not
> >really sure.
>
> Well, I think that in this case, The Great Umpire sneakily tampers
> with the relative rates of the players' wristwatches, and then
> sneakily alters their overall rates of timeflow by the same amount so
> that they don't know who to blam efor the discrepancy!
> <heh heh
>
>
>
> Seriously, though, the basic form of the problem probably goes back
> over a century, we have:
>
> 1: the idea that light changes energy as it crosses a gravitational
> gradient,
>
> 2: the idea that this energy-change shows up as a change in the
> character of the light, rather than as a change in quantity (change in
> wavelength rather than amplitude, Michell, 1783),
>
> 3: and then at some time during the 1800s we probably have the
> corrected relationship between energy and frequency, telling us that
> energy-gain is associated with a blueshift and energy-loss with a
> redshift (Newton seemingly got that bit back-to-front).
>
> And by this point, some time during the C19th, we have all the pieces
> in place for the clock problem. Loads of mathematicians and physics
> people must have looked at it, chewed the ends off their pencils, and
> then binned their calculations because they couldn't find any possible
> way to resolve the issue without allowing the clocks to run at
> dfifferent rates.
> Einstein comes along, looks at the problem, and publishes it as-is,
> saying that since there doesn't seem to be any conceivable
> agreed-clockrate solution ... the clocks would seem to be running at
> /different/ rates. <ker-ching!
> It's such a simple argument, that I'm sure a lot of researchers were
> spitting blood for not having taken the math seriously and published
> it themselves. Doh!
>
> -------------------
>
> We can also run the idea backwards.
> If we start off with the idea that two regions have different rates of
> timeflow (with a transitional region in between), then if we try to
> aim a pulse of light between the two regions, at right angles to a
> line joining them, then since the fast side of the wavefront should
> advance faster than the slow side, the pulse should end up being
> steered more towards the region of slowest lightspeed (eg refractive
> index arguments), and an attempt to aim a lightbeam along the line
> should result in the lightbeam being bent.
>
> If we then try to throw a ball along this line, if the EM and other
> forcesinside the ball are deflected in the same way, including the
> forces in equilibrium inside the atoms comprising the ball, then the
> change in internal equilibria should result in the ball's trajectory
> also being smoothly deflected towards the region of slowest
> lightspeed.
>
> Finally, if we simply place a ball between the two regions, the same
> sort of imbalance in inertial forces inside the ball ought to make it
> start to magically start moving towards the slow-lightspeed region,
> picking up speed as it goes, even if the ball is initially not moving
> when it is deposited in the region.
>
> So if we start out by assuming a gravitational differential we seem to
> end up with a description of a "timeflow" differential, and if we
> start out by assuming a timeflow differential, we seem to end up with
> a description of something that seems to be indistinguishable from a
> "real" gravitational field.
>
> So the arguments for gravitational differentials and timeflow
> differentials seem to be very tightly intertwined, and that kinda
> suggests that the two ideas may actually be synonymous, or at least
> strongly interdependent in some way.
>
> Newton already said that a gravitational field seemed to be associated
> with a change in density of the light-aether (= an apparent change in
> spatial density), so going one step further and saying that yes,
> gravity warps a light-metric, but it can also be said to warp apparent
> temporal coordinates as well as spatial ones ... I really don't think
> that it's a big step.
>
> =============
>
> PS: "Believing" in gravity-shifts doesn't seem to necessarily require
> one to "believe" in special relativity (if that's what's worrying
> people), because the gravity-shift idea can be implemented using the
> SR shift equations, =or= by using the older Newtonian set.
> There's two different available routes, here.
>
> Using the SR set as a starting point for gravitaitonal theory
> generates simpler, "tidier" gravitational physics (it's arguably
> responsible for GR's simple clean inescapable black holes, for
> instance), but since we don't seem to live in a simple and tidy world,
> I think that the SR-based gravitational theories are more like "toy"
> models, easy to play with but not to be taken too seriously.
> I think that the "Newtonian" set is far more powerful and gives us
> more "sophisticated" gravitational physics, and a more powerful set of
> tools to work with.
>
> It's possible to "approve of" a lot of the GR arguments without
> neccessaily "approving of" special relativity.
>
> =Erk= (Eric Baird)
> : "Nobody cares anything about history any more"
> : -- Captain Atom, "Justice League Europe"

A thoughtful narrative Erk, Thank you.
Yes, imaginary axes don't have to be proven real to plot and operate
on them. A geomerty based on the speed of light is powerful tool to
decribe a world where nearly everything is affected by it. As with
Hilbert space, the trouble begins when folks forget from wince ;-) it
came.
Kind regards,
Sue...

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