But you haven't really given an argument for why there "has to be something happening in Andromeda right now simultaneously with what's happening here on earth for cosmology to make sense"--that seems to be just an assertion of faith on your part. Cosmology is perfectly coherent as an attempt to determine the geometry of 4D spacetime and the matter/energy distribution within it, based on what we can observe in our past light cone.
Dividing a 4D spacetime into a series of 3D hypersurfaces of simultaneity is what is known in general relativity as a "foliation", and although some foliations may make calculations a bit easier, fundamental physics works the same regardless of what foliation you choose. So yes, in cosmology it's common to choose a foliation where curvature is constant across space, and the density of matter is constant too. But if someone came up to you and said "I agree there must be an absolute present, but I think you're wrong about the foliation it matches up to, I had a dream where God told me it was this alternate foliation", would you have any reasoned argument for why your preferred foliation *must* be the one that lines up with absolute time, or is your view just as faith-based? Besides, this sort of foliation in which one picks "homogeneous" hypersurfaces of simultanity is only precisely-defined in an idealized cosmological model (the Friedmann–Lemaître–Robertson–Walker metric) where there are no local deviations in the density of the cosmic matter "fluid". The local warpings from galaxies and such may be small on cosmic scales, but they would introduce an ambiguity into how to define the "correct" hypersurfaces of simultaneity that correspond to absolute time, even if one accepts your basic intuitions. Jesse On Fri, Dec 27, 2013 at 12:55 PM, Edgar L. Owen <edgaro...@att.net> wrote: > Brent, > > Thank goodness, some sanity and clarity! > > Yes, you are correct and that is pretty much what I'm talking about. It's > quite easy to understand really. There has to be something happening in > Andromeda right now simultaneously with what's happening here on earth for > cosmology to make sense. The fact that clock times cannot be > instantaneously communicated between the two does not negate that. That > common, though admittedly non-communicable, 'right now' is the shared > universal present moment I keep talking about. > > It's quite a simple straight forward and intuitive concept, nothing > esoteric at all.... Basic common sense really..... > > Thanks Brent, I should have mentioned this myself.... > > Edgar > > > > On Thursday, December 26, 2013 3:26:28 PM UTC-5, Brent wrote: > >> On 12/26/2013 8:12 AM, John Clark wrote: >> >> On Mon, Dec 23, 2013 at 2:10 PM, Edgar L. Owen <edga...@att.net> wrote: >> >> > The proof is simply the fact that the time traveling twins meet up >>> again with different clock times, but always in the exact same present >>> moment. This proves beyond any doubt there are two kinds of time, clock >>> time which varies by relativistic observer, and the time of the present >>> moment (what I call P-time) which is absolute and common to all observers >>> across the universe. >>> >> >> It's all a question of simultaneity, sometimes observers can agree that >> 2 events were simultaneous, and sometimes they can not, it all depends on >> the circumstances; and the amount of disagreement can vary from zero to as >> large a value as you'd care to name. So I don't see why zero is more >> special or "absolute" than any other number. >> >> And nothing that happens in the Andromeda Galaxy 2 million light years >> away can have any effect on me for 2 million years, and nothing I do can >> have any effect on Andromeda for 2 million years. So even asking "what are >> things like right now on Andromeda?" is a ambiguous question. Does it mean >> how things look in my telescope when light left Andromeda 2 million years >> ago? Or does it mean Andromeda 2 million years in the future when something >> I do here can make a change there? So what does "right now" even mean? >> >> >> It does have a meaning in most models of cosmology. "Now" is defined by >> a comoving frame in the expanding FRW universe. Operationally it means >> anybody who sees the CMB at the same isotropic temperature is sharing the >> same "now". But this is selecting a preferred frame based on empirical >> boundary conditions. Edgar refers to his P-time as being related to >> curvature of spacetime, so maybe this is what he's talking about, but in >> spite of my asking several times he hasn't replied. >> >> Brent >> > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to firstname.lastname@example.org. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to email@example.com. Visit this group at http://groups.google.com/group/everything-list. 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