Tom Roberts wrote:
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http://www.everythingimportant.org/relativity/simultaneity.htmYour discussion at that URL is, as I have said several times, self-inconsistent because it assumes a flat spatial metric on S^3.
Your very imaginative accusation that I assume a flat spatial metric is without foundation. Why not post an incriminating excerpt?
Tom Roberts wrote:
In particular, your coordinates do not apply to any FRW manifold.
My coordinates apply to Einstein's hyperspherical spacetime (S^3)xR but there's no point in considering the non-static case, i.e., the FRW's model, if you don't understand the implications of the static case.
Tom Roberts wrote:
But in any case, I don't see how the global structure at scales ~billions of lightyears can affect the structure near a black hole with scale ~fraction of lightyear.
Your seeming inability to grasp the restrictions imposed by my global theorem stems from your reluctance to understand SxR in one spatial dimension and to openly declare a right judgment about it.
Tom Roberts wrote:
For the overly-simplistic case of a (1,1)-dimension manifold you have deduced there is a "global time order". You then seem to think that any manifold you can force into that mold must also have a "global time order". You have ignored my warnings that your "global time order" is a PUN,
I have posted
direct challenges to your belief that an "absolute time order" is just semantics.
Tom Roberts wrote:
and some aspects that one would expect of a "global time order" do not apply; yet you apply them anyway.
And some of your attempts to refute what I say are clear. In this instance, what you say is obviously just totally empty obscurantism.
Tom Roberts wrote:
In particular, you have made no attempt to apply your approach to Schwarzschild spacetime. Do so and you will quickly find that it, too, has a "global time order" in the sense you use that phrase[#].
My argument for an "global time order" is based on the straightforward, overwhelmingly conclusive and easy to see constraint that topology imposes on definitions of simultaneity. Without the restrictions imposed by a global topology, I see no valid or analogous proof that may be generalized to Schwarzschild spacetime.
Tom Roberts wrote:
[#] I.e. there are physically-distinguished "global" coordinates in which spacelike-separated events have a definite time order.
That's not a quote from me nor does it embrace all that I have specified in my view of an absolute time order.
Tom Roberts wrote:
Sidebar:
When I see the phrase "global time order", I expect that ANY observer using ANY coordinates will observe ANY pair of events to have that "global time order"
OK. Let's see your coordinate independent definition of "global time order" for Galilean spacetime (S^3)xR in wacky coordinates. I remind you that any two inertial frames of reference in an ordinary Newtonian universe, governed by Galilean spacetime, have an Einsteinian synchronization.
http://www.everythingimportant.org/relativityTom Roberts wrote:
-- what else could it possibly mean to justify the use of the word "global"??? -- Neither Schw. spacetime nor yours have this property. In fact, no Lorentzian manifold of GR can have this property.
I don't even believe that Galilean spacetime has the property, as you would define it.