Re: Red shift and homogeneity

Jim Greenfield wrote:
> 
> "George Dishman" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
> > "Jim Greenfield" <[EMAIL PROTECTED]> wrote in message
> > news:[EMAIL PROTECTED]
> > > "George Dishman" <[EMAIL PROTECTED]> wrote in message
> >  news:<[EMAIL PROTECTED]>...
> > > > "Jim Greenfield" <[EMAIL PROTECTED]> wrote in message
> > > > news:[EMAIL PROTECTED]
> > > > > "George Dishman" <[EMAIL PROTECTED]> wrote in message
> >  news:<[EMAIL PROTECTED]>...
> > > > > > "Jim Greenfield" <[EMAIL PROTECTED]> wrote in message
> > > > > > news:[EMAIL PROTECTED]
> > > > > >
> > > > > > Let's try imagining that the universe existed before the bang
> > > > > > and use Jeff's diagram again. I'll change the labels a little:
> > > > > >
> > > > > > > > -2 C-B-A
> > > > > > > > -1   CBA
> > > > > > > >  0     *
> > > > > > > >  1     ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqr
> > > > > > > >  2     A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-
> > > > > > > >  3     A--B--C--D--E--F--G--H--I--J--K--L--M--N--O-
> > > > > > > >  4     A---B---C---D---E---F---G---H---I---J---K---
> > > > > > > >  5     A----B----C----D----E----F----G----H----I---
> > > > > > > >  6     A-----B-----C-----D-----E-----F-----G-----H-
> > > > > > > >  7     A------B------C------D------E------F------G-
> > > > > > > >  8     A-------B-------C-------D-------E-------F---
> > > > > > > >  9     A--------B--------C--------D--------E-------
> > > > > >
> > > > > > In this simplification, all the galaxies have constant speed
> > > > > > from some time before the bang to the present, hence no
> > > > > > acceleration is needed. We don't know what happened in the
> > > > > > very earliest era but if particles were created with entirely
> > > > > > random speeds, what we see would come about automatically
> > > > > > because the distances would grow in proportion to the speeds.
> > >
> > > For any speed greater than 0, an accelleration MUST have happened at
> > > some time. It's a bit rich to ignore it eh?
> >
> > For any _change_ of speed. You are assuming matter was created
> > from the initial energy all with identical motion throughout the
> > expanding universe. It's a bit rich to ignore the then ongoing
> > expansion, eh?
> 
> Distant galaxies have a speed of say 3000k/sec (is that about right?).

Using a linear Hubble law, this gives a distance of around 43 Mpc. I
don't
know if a cosmologist would call this "distant".


> So if this is 1% c, then since BB

Err, their speed has been greater in earlier times. The expansion has
slowed down since the BB. they have only increased the


> distance from their point of formation relative to us by 1% of (say)
> 12 bly = 120 mly.

Where do you get these 12 bly from?


> What has been the expansion since BB?- surely more than 1%

Your calculation above doesn't show that the expansion of the universe
was only 1% since the BB. Why on earth do you think so?

(and it is wrong right from the start, because you don't consider that
the speed was higher in the past)

[snip]


> > > You know my view of radiation pressure by now. I think that EMR has
> > > good old Newton type kinetic energy, and "pressure" is really only
> > > "bombardment"
> >
> > I think you meant "good old Newton type momentum" but otherwise
> > that is the conventional view. Photons carry momentum just like
> > flying bricks.
> 
> My bricks might have an angular momentum to (spin along their axis of
> travel)

Photons have spin. So what?


> ... and I am very pleased to see EMR given credit for having mass....

Photons have so-called "relativistic mass". They don't have *rest* mass.
See
<http://www.physics.adelaide.edu.au/~dkoks/Faq/Relativity/SR/light_mass.html>.

[snip]


> > > If I deflate the balloon, the points on the surface still proceed
> > > towards a center though
> >
> > Sure, they proceed towards a time 13.7 billion years ago,
> > everywhere. That is not a location, it is a time.
> 
> And they take the matter of the universe to that time???

Yes.


> In that case
> the matter hasn't actually "gone" anywhere-- so no
> deflation/expansion.

Well, in principle you are right - expansion of the universe doesn't
mean
that matter is moving, but that the space *between* matter expands.
Obviously this *looks* like if matter were moving.

But I don't understand your line of reasoning here - how do you get from
the first sentence ("and they take...") to the second ("in that case the
matter...")?


[snip]


> > > Yes, that seems to be pretty terminal for my ideas. I note that
> > > astronomers filming for different frequencies from the same source,
> > > find it in the same location (and not even blurred dammit). I'm not
> > > quitting on different c's for now though. I was thinking along Sean's
> > > line, ref different blue/red speed, and we need a factor of what? 22
> > > days/several billion years difference from standard c- certainly
> > > nowhere enough.
> >
> > The light curves for SNe in different colour bands peak
> > roughly together though there is some variation. There is
> > no reason to think it is anything other than the gradual
> > change of what is emitted as the fireball expands and the
> > materials evolve (radioactive decay, turbulence, bouyancy
> > and so on).

Did you get this?


> > > What if you let me add source dependency, and say that the light form
> > > this side of the gas cloud has the expansion speed added, and from the
> > > rear subtracted? Does that help me (and maybe Sean) out?
> >
> > Binary star observations and the Sagnac experiment rule
> > out source dependency and to be honest I don't see why
> > you think it would help anyway. We can't see the rear,
> > only the side facing us.
> 
> Binary stars DO exhibit Doppler fluctuations in frequency,

Yes, no one dispute that the *frequency* of light depends on the
velocity of the observer relative to the source. But you, on the other
hand, claim that
the *velocity* of the light depends somehow on the velocity of the
source. (or did I misunderstand you?)


> and as I
> have argued before, I think that this IS evidence of source dependency
> of EMR propogation.

Could you please tell me how you arrive at this conclusion?


> If the SN explodes as a bubble, we at least see from the edge (speed 0
> relative to us) to point nearest (coming straight at us at speed of
> expansion)

Right. So what? What do you want to imply?


Bye,
Bjoern