Re: Tired Light in the Valley of the Trolls
From: greywolf42 (mingstb_at_marssim-ss.com)
Date: 06/09/04
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Date: Wed, 9 Jun 2004 10:08:44 -0700
Old Man <nomail@nomail.net> wrote in message
news:05CdnX8qStevpVvdRVn-vw@prairiewave.com...
>
> "greywolf42" <mingstb@marssim-ss.com> wrote in message
> news:10cbpep8fb87fa9@corp.supernews.com...
> > Old Man <nomail@nomail.net> wrote in message
> > news:U9OdnX38f6p1PF7dRVn-ug@prairiewave.com...
> > >
> > > "greywolf42" <mingstb@marssim-ss.com> wrote in message
> > > news:10c6jo5ppltbv44@corp.supernews.com...
> > > > Old Man <nomail@nomail.net> wrote in message
> > > > news:LNKdnY0hrdtO9l_dRVn_iw@prairiewave.com...
> >
> > {snip higher levels}
> >
> > > > > Contrary to greywolf42's careless assertion, GTR and
> > > > > BBT do not predict the observation of cosmological red-
> > > > > shift within gravitationally bound systems.
> > > >
> > > > You mean that they simply ignore it as a minor correction, that can
be
> > > > ignored in most calculations. They certainly don't postulate that
the
> > > > universe stops expanding because the systems are 'bound.' Spacetime
> > > > does not 'know' if the objects are going to be 'bound.'
> > >
> > > Funny ! No it's not a postulate as is TLT.
> >
> > Cosmological redshift is not a postulate in Tired Light theories.
> > (Hint: That's the whole point.)
No comment, I see.
> >
> > > It's a consequence
> > > of strong space curvature within galactic groups, that is, net
> > > attractive gravity, of which the expanding Universe is generally
> > > devoid. Not at all complex. The prediction is quantitative.
> >
> > You are simply describing the fundamental assumption. Whether or not a
> > particular region contains 'net attractive gravity' is irrelevant to the
> > overall expansion of the universe.
>
> greywolf42 is in serious error. Expansion of space isn't an
> assumption.
Expansion of 'space' is an assumption of the BB theory. Expansion of space
does not take place in tired light theory, or in steady-state cosmologies,
or in the original BB (primeval atom). Though matter may expand *through*
space.
> Empty space isn't predicted to expand. Space
> that contains only (non-relativistic) matter without curvature
> is predicted to expand with time as
>
> a(t) / a(t0) = (t / t0)^(2 / 3)
>
> The presence of matter causes the expansion of space,
> and the presence of net attractive gravity, space curvature,
> opposes the expansion of space.
According to the BB, the expansion of space was caused by the Big Bang
event. Not by the current presence of matter.
> > > > Plus, gravitationally 'bound' systems are ephemeral. Be it stars or
> > > > galaxies. They tend to 'evaporate' by kicking out the smaller
> > > > members. (Just like journals.)
> >
> > No comment, I see.
>
> greywolf42's interjection is fragmentary and irrelevant. Old
> Man chooses to ignores greywolf42's audacious application
> of intellectually dishonest tactics of debate.
You made the claim that the operation of the comos can be changed by the
presence of a 'bound' gravitational system. I merely pointed out that there
is no such thing as a multiple 'bound' system that is not also highly
ephemeral. Hence, it cannot be cosmologically significant.
> > > > > That exception
> > > > > is a quantitative prediction of GTR.
> > > >
> > > > Reference, please. (How does one quantify a claimed non-effect?)
> > >
> > > No problem. Read and learn:
> > >
> > > "An Introduction to Cosmology"
> > > 2003 Barbara Ryden ISBN 0-8053-8912-1
> > >
> > > More difficult, more comprehensive, but still fun:
> > >
> > > "Principles of Physical Cosmology"
> > > 1993 P.J.E. Peebles ISBN 0-691-01933-9
> > >
> > > Old Man gives those references because greywolf42 is in
> > > need of a tutorial on the Friedmann equation. The subject
> > > of interest here is found under "Matter + Curvature"
> > >
> > > It's very simple. Basically the Friedmann equation says
> > > that the (square of) expansion rate is equal to the difference
> > > of two terms. The first contains the energy density, and
> > > the second contains the inverse square of curvature radius.
> > > Less than infinite radius of curvature slows the expansion.
> > > On a large scale, space in our universe is thought not to be
> > > curved, but a group of bound galaxies contains strong
> > > gravitational fields, that is, space curvature, which is strong
> > > enough to bring the expansion to zero. Even weak curvature
> > > will eventually bring expansion to an end.
> >
> > I think you have made a simple error. A bound system (or even a
> > collapsing system) does not alter the fundamental cosmological
> > expansion of the universe. (The collapsing system would be
> > collapsing faster, if not for the overall cosmological expansion.)
>
> No. Old man isn't mistaken. From the references given,
Repeating a statement, or quoting a reference, does not make the statement
true.
> Hubble's constant for a Universe of matter without curvature
> is given by
>
> H(t)^2 = [a'(t) / a(t)]^2 = [8 pi G / 3 c^3] E(t)
>
> Where E(t) is the uniform energy density. If E = 0 (free
> space), then H = 0 for all time. No energy, no expansion.
> Space curvature subtacts from H
>
> H(t)^2 = k1*E(t) - k2 / R^2*a(t)^2
>
> Where R is the positive curvature of space, and a(t) is the
> scale factor, a(t =0) = 1 at present. k1 & k2 are constants.
>
> greywolf42 is woefully ignorant of BBT and the Friedmann
> equation.
> The expansion of free space isn't intrinsic. Matter
> is causal to the expansion of space, and the presence of net
> attractive gravity, space curvature, opposes the expansion of
> space.
>
> The curvature of space within gravitationally bound systems
> reduces that expansion to insignificance,
The only problem with your statement is that your (understanding of) the
theory does not affect the fact that redshift *IS* noted among the local
group. The kernel of the BBT (the redshift-distance relationship) is based
on a scattershot pattern among the local group (the closest 20 galaxies)
with an overall observed redshift-distance relationship.
> > Note that I did not claim that galaxies can never be gravitationally
> > attracted to the point that they coalesce.
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}
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