Re: Swift grb satelitte

From: Bjoern Feuerbacher (feuerbac_at_thphys.uni-heidelberg.de)
Date: 02/14/05 

Date: Mon, 14 Feb 2005 14:09:04 +0100

sean wrote:
>
>>>My impresssion is that in physics there
>>>are no coincidences.
>
>
>>I agree. Here are some more:
>
>
>>* White dwarfs should shine for tens of billions of
>> years but the oldest we see locally are of the order
>> of twelve billion years old.
>
>
> Yes, that is proof. But not neccesarrilay ruling out
> the possibility that white dwarfs older than 12 billion
> years are below the visibilty threshold

That would imply that there is something seriously wrong with
our ideas of stellar development, which indicate otherwise. Even
that something is wrong with some fairly basic thermodynamic calculations!

The "shining time" of white dwarfs can essentially be calculated
from simple thermodynamics: the light comes simply from the huge
temperature they have. The only ways for them to be under the
"visibility threshold" would be if they
1) become too cold to emit any measurable amount of light - that
takes tens of billions of years, if thermodynamics isn't totally
wrong
2) become smaller and smaller, or are small right from the start.
No mechanism is known how that could happen.

> and/or the other
> possibilty that our galaxy is less than 13 billion years
> old.

Can't we see white dwarfs also in other, at least nearby, galaxies?

[snip]

>> Unlike our galaxy, observations of galaxies
>> 10 billion light years away suggest they contain
>> mostly young stars, perhaps in the range 1 to 2
>> billion years old.
>
>
> The maths of these calculations is beyond me but could
> it also be explained as the older cooler stars just
> are not visible at distances like this?

Older stars are not necessarily cooler, and even less necessarily
dimmer. White dwarfs are quite old stars, but among the hottest stars
known (but also in general quite dim, since they are so small). Red
giants are also old stars, but among the brightest stars known.

> After all
> the article on white dwarfs suggests just the same
> problem with the white dwarf survey in that they had
> to look at the closest source of white dwarfs to get
> a reliable survey within our galaxy and even that was
> at the very limits of `visibilty`.

But white dwarfs *are* old stars, so you seem to contradict
yourself here.

[snip]

> Its like the SN data that I discussed on astro research.
> I notice that the data is tested only for the
> preffered theory of expansion and then when it
> *sort of fits* they say `Oh that rules
> out any other theory`. Without testing whether
> the data fits an undilated non expanding template
> (which it does as I have shown on astro research)

Err, I explained in detail why a fit to undilated
templates would give the same results. I gave a specific example,
I gave formulas etc. My last post was on January 26th. You haven't
answered it so far.

It was explained ad nauseum to you (not only by me, but also by
Steve Willner and several other people) that the fitting
procudure used would have *noticed* if there had been no
time dilation in the SN light curves. You still fail to get
the argument.

Also, you haven't demonstrated that a fit to an undilated
template would be *better* fit.

> So yes, these you cite above are coincidences that
> support BB but they can also all be shown to
> support non expansion as well.

So far, you haven't shown that.

>>* Stars can be dated by radioactive decay and give
>> similar results (Look up "cosmochronometry").

Care to address that?

>>* WMAP gives an age of 13.7+/-0.2 billion years from
>> the angular power spectrum of the CMBR (though this
>> uses some other results and is less independent).
>
>
> This is about the best so far for BB but I would
> still prefer it if the experts had made an attempt
> to see if a non expansing universe could have given
> these results.

Ever heard of Hoyle and Narlikar?

Also, how do you reconcile a non-expanding universe with
General Relativity, or even Newtonian gravity? Do you suggest
something which exactly balances gravity, or what?

Additionally, did you notice that if one takes the data from WMAP,
calculates the density fluctuations necessary to reproduce the
seen temperature fluctuations, and then runs a computer simulations
to see how these density fluctuations grow with time (using an
expanding universe!), one gets the large-scale structure we see today
in the universe?

For a particular example which was recently in the news, see here:
<http://www.newscientist.com/article.ns?id=dn6871>

> I dont know enough myself to do the
> test (as I have done with SN1a data where I can
> show that the data also fits no expansion )

That's by far not enough. You have to show that the fit to
"no expansion" is *better* than the fit to "expansion".

And the results of Knop et al. and over groups show the
*opposite*: the best fits (by far!) are indeed for "expansion".

> For instance doesnt hydrogen have more than 1 emmision peak?

If you talk about recombination lines of atomar hydrogen: yes.

> Shouldnt there be more than
> one redshifted peak in the microwave frequencies as
> a result?

Err, the CMBR is the result of black-body radiation, not of a peak
from hydrogen emission.

[snip]

> Incidentally I worked out my GRB model in `92 and
> predicted *then* that they would not be found within
> our galaxy which was the prevailing wisdom of the time
> I also predicted that they would all have afterglows in
> other wavelengths , longer for longer wavelengths.
> All these predictions were verified which is why
> I am so convinced no redshift will be found.

How did you manage to predict all that?

[snip]

Bye,
Bjoern

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