Re: CMBR and neutron stars

Dear Martin Brown:

"Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in
message news:de1h4p$h3c$1@xxxxxxxxxxxxxxxxxxxxxxx
> N:dlzc D:aol T:com (dlzc) wrote:
>>
>> "Steve Willner" <willner@xxxxxxxxxxxxxxx> wrote in message
>> news:4303a492$1@xxxxxxxxxxxxxxxxxxxxxxxxxx
....
>> But "we" have GR, and particular models in GR sound like they
>> might *also* provide a black body curve, if outer-time is
>> integrated over the surface, and the coordinate r_outer =
>> t_inner_Big_Bang is the instant that all infall must pass.
>
> Viewed from the outside of the BH you fade away at ever more
> extreme gravitational redshift as you cross the surface of the
> event horizon. But in the comoving frame nothing exceptional
> happens to you crossing the event horizon provided that you
> choose a nice large quiescent BH. You will have considerable
> difficulty reporting any observations though.

Thanks for the reasoned response, Martin.

What if your "report" is directed inside? They have no problems
getting the message. The difficulty seems to be in "our"
expectations of what happens inside. In our Universe, if the Big
Bang is "just inside the event horizon" (by any finite
distance/age), we should see no new structures dropping in
wholesale. If outer-time is not "integrated across all time",
then new objects or new basic building blocks (at least) should
be periodically discovered crossing our light cone, and our
Universe ingests more of the outer.

>> Well my "problem" will end up being one very similar to the
>> constant creationists. How do you have a (potentially)
>> infinite series of formed Universes, and not have only-iron
>> left? Seriously, if we contain black holes, likely some of
>> them formed "day one", why should our position in the "chain
>> of Universes"
>> be particularly different than any other? I'll try carving
>> out the parts, and see if they fit into anything that someone
>> can use.
>
> It might be worth your while looking at some of the existing
> multiverse hypotheses before you go too much further.

I did reinvent the wheel once... ;>)

> One idea floated there is that inside each BH in a given
> universe but isolated from it
> quantum fluctations can create an ensemble of new
> universes with inherited (or random) choices for the
> constants of nature. It has some appeal but as far as I can see
> it is not amenable to observational testing.

That is an issue, of course. Perhaps "dual to black hole"
experiments can shed some additional light...

> You might find Martin Rees book "New perspectives in
> Astrophysical Cosmology" worth a look.

Queued.

>>>>The event horizon *is* a singularity. No?
>>>
>>>No, of course not, at least not a physical singularity.
>>
>> A neutron star is the most dense, physcially stable state.
>> Are you so sure?
>
> We can't be certain. ISTR a few serious papers have been
> written
> about the possibility of another repulsive force kicking in at
> ultra
> high energies to avoid the singularity forming at the centre of
> a BH.

Sounds like Steve Willner's "new physics".

>>> It is a
>>>coordinate singularity in some coordinate systems,
>>>just like the Earth's north pole.
>>
>> I disagree. I don't think we "flatlanders" can sit back here
>> and say that. Not and be entirely serious. Yes, coordinates
>> based on "mostly flat space theory" points to a mathematical
>> singularity. But physical theory points to physical
>> singularities even before the event horizon is formed. And
>> this has nothing to do with "a choice of coordinate systems".
>
> There is a significan singularity in the mathematical and
> physical
> sense at the centre of a BH (assuming the classical geometrical
> interpretation of GR). But there is nothing so special about
> the
> event horizon beyond it being rather like a semipermeable
> membrane for energy and matter.
> (loose use of words that may get me into trouble)

Seems to not have bitten you.

The rate of information interchange with the Universe at large is
statistically zero, however. (My intention is photon-based
information transfer from the EH outwards.) So this leaves only
quantum interchange to transmit curvature, charge, and "angular
momentum".

>> I do appreciate the link, and the effort. I will go there
>> next. Is there a similar study for the spectra of our Sun?
>
> Try:
> http://www.shef.ac.uk/physics/teaching/phy103/solspec.html

Thanks!

David A. Smith


.

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