Re: Cosmic acceleration rediscovered

From: George Dishman (george_at_briar.demon.co.uk)
Date: 12/31/04 

Date: Fri, 31 Dec 2004 12:25:23 -0000

"greywolf42" <mingstb@marssim-ss.com> wrote in message
news:FI2Ad.32991$Bw5.29243@news.flashnewsgroups.com...
> George Dishman <george@briar.demon.co.uk> wrote in message
> news:cqgl0m$u9d$1@news.freedom2surf.net...
>>
>> "greywolf42" <mingstb@marssim-ss.com> wrote in message
>> news:s7Iyd.419$Bw5.333@news.flashnewsgroups.com...
>> > George Dishman <george@briar.demon.co.uk> wrote in message
>> > news:cqabiq$9pu$1@news.freedom2surf.net...
>
>> >> H_0 has the empirical value 71km/s per MPc which
>> >> means dE/E is about 0.024% per MPc hence R is
>> >> about 4.2GPc.
>> >
>> > Ah! Now I see where you are going. I think you are approaching this a
>> > bit sideways, but we should be able use this approach.

<snip stuff on units>

>> > The current value of the slope of H_0 includes some specific BB
>> > assumptions.
>>
>> The best current value uses the angular power
>> spectrum measured by WMAP and that method I agree
>> is likely only to be applicable in a BB model.
>> However, the older technique of measurements of
>> nearby source for which distances can be found
>> from the distance ladder using parallax, Cepeids
>> and so on is equally valid for determining the
>> constant in tired light models. The difference
>> is that the uncertainty will be higher.
>
> The uncertainty in the observation of redshift vs. distance is unchanged.
> Regardless of how the WMAP theoreticians tweak their computer models.

The uncertainty in the value if you exclude the
WMAP observations on the basis that they assume
a BB model will be poorer than if you include
them. However, I think it will still be within
a factor of 2 even limiting the data to methods
that don't assume a BB model. It is for the tired
light proponents to do that calculation though but
I think we can use a factor of two for the sake of
discussion.

>> > However, for the purposes of this exercise, I will accept your values
>> > are in the ballpark (roughly a factor of 2, if I converted correctly).
>>
>> That's another test you can apply to a tired light
>> model. A factor of 2 is probably about as much as
>> the uncertainty would allow but it would be hard
>> to say without looking at the detail of the
>> determination so I'm happy to accept that for the
>> moment.
>
> The point is, that tired light theoreticians usually don't require that
> *ALL* the redshift be due to tired light. We try to avoid the trap that
> caught the big bangers.

OK, it only makes your task harder as there are more
unknowns for you to tie down before you can claim you
have a workable theory. However, you haven't mentioned
this before so bear in mind my previous comments were
made on the basis of what you had said.

> I.O.W., the redshift-distance relation may include contributions from
> different effects (at least in theory). Which could shift the onset of
> the
> nonlinear deviation. (For example, a combined Vigier-tired-light and
> plasma-"fireworks"-expanding-galaxies model.)
>
>> > Sidenote: LeSagians and tired light types usually use the variable mu;
>> > which may be calculated from material/aether properties (EM and
>> > gravitational). We typically don't use the resulting characteristic
>> > distance, R (which is back-calculated, or ad hoc). R and mu are
>> > inversely related.
>>
>> Your last two sentences appear to be in conflict.
>> If mu can be derived from the theory, then just
>> tkae the uinverse
>
> Tired light theories do not deal with universes. That's the big bang.

I don't understand your comment. If mu can be found
from theory and R is just the inverse of mu then R
can equally well be said to be derived from theory.

>> and you have a theoretical value
>> for R. That can then be compared to the observed
>> value described above as a test of the theory.
>> Neither value is ad hoc.
>
> The ad hoc referred to the use of tired light theory *solely* to explain
> the
> redshift (the way the big bang started). Values -- per se -- are never ad
> hoc. It is how they are used that obtains the ad hoc description.

Tired light AIUI is suggested to explain only the
large scale variation with distance. Obviously
gravitational redshift and Doppler due to proper
motion add to this. If you are now introducing
another factor perhaps you could explain the
details.

> {brought over from parallel thread}
>
>> >> Agreed, and since the value is now being measured
>> >> by observation, it clearly meets your criterion.
>> >
>> > The point is, that neither the shape, nor value was predicted by the
>> > BB.
>> > It is another ad hoc fit to the BB. The shape of the curve *was*
>> > predicted by *all* tired light theories. The value was predicted
>> > by some.
>>
>> Ok, you have been reading the posts between Bjoern and
>> me so can you clarify that.
>
> Yes, I've amused myself watching you and Bjoern pat each other on the
> back.
>
>> You have said the exponential
>> form fits the measurements, but in most tired light
>> theories the energy is exponential with distance while
>> what is observed is redshift versus magnitude or some
>> other indirect measure of distance.
>
> You are correct that what is observed is redshift versus some indirect
> measure of distance (since we can't do parallax that far). Since energy
> is
> exponential with distance in tired light theories, so is redshift.

"in .. theories"

>> Precisely which
>> relationship between _measured_ values is predicted by
>> tired light theories?
>
> The relationship between redshift and actual distance will be exponential.

"will be"

> That is, at the low-redshift (low z) distances, you will have an
> apparently
> linear relation that is equal to the first part of the exponential series
> expansion. This relation will begin to deviate from linear as
> higher-order
> terms become important at longer distance. The entire curve will be

"will be"

> exponential.

All the above say that it should be exponential in theory,
but what we are asking is how you turn that into the claim
that the exponential has been observed as a result of the
paper you cited.

> Using your data, above, dE/E is about 0.024% per MPc. And every photon
> loses about 63% of its energy every 4.2GPc.

Actually that is now wrong if you are saying that part of
the redshift is due to "plasma fireworks", "expanding
galaxies" or whatever. How does the 0.024% split between
tired light and these other mechanisms?

(I'll reply to your other posts as time permits).

George

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