Re: CMBR and neutron stars
- From: "N:dlzc D:aol T:com \(dlzc\)" <N: dlzc1 D:cox T:net@xxxxxxxxxx>
- Date: Fri, 12 Aug 2005 20:30:10 -0700
Dear Steve Willner:
"Steve Willner" <willner@xxxxxxxxxxxxxxx> wrote in message
news:42fd0815$1@xxxxxxxxxxxxxxxxxxxxxxxxxx
> In article <TtTKe.19601$E95.19390@fed1read01>,
> "N:dlzc D:aol T:com \(dlzc\)" <N: dlzc1 D:cox T:net@xxxxxxxxxx>
> writes:
>> The dominant light source in our Universe is the CMBR.
>
> Are you sure about this? I would have guessed that the
> integrated stellar output would be greater. References
> I find in a quick search seem inconclusive but suggest
> the two sources are comparable.
Now expand the stars away from the hole, in an expanding
Universe. The intensity goes down, as the light is also red
shifted. It is my question... not some hokey "answer" I am
shoving down anyone's throat.
>> Even here
>> in the middle of the Milky Way, our nightside transfers
>> heat to a ~5K source.
>
> Didn't we argue over this before? I was never clear exactly
> what you
> were asserting. In any case, 5 K is about 12 times brighter
> than the
> microwave background.
We actually didn't argue. I think you asked for a reference
though, which I could not provide. I heard this in the mid
80s...
>> I think it is a whole lot like a black body, if you
>> integrate light infall over the "lifespan" of a BH. It might
>> not
>> be if the BH is a close companion to a donor star...
>
> The light spectrum inside a galaxy -- which presumably is
> where most black holes are located -- is nothing like a
> blackbody. Anyway, your original assertion was that
> incoming radiation would be isothermal, which the
> microwave background certainly is not. Its temperature
> decreases with time.
Steve, I am not *asserting*, I am asking. The CMBRM is opaque
and isothermal (as I was assured). I am asking if the inside of
an event horizon would not also appear to be opaque (in some
reasonably butchered definition) and isothermal, *IF* Kruskal
coordinates come anywhere near describing reality. If you
integrate the entire light history of light passing an average
point/volume "somewhere", over a period of time shortly after the
Big Bang, to say, 100 Gy, would the entire history so delivered
not be "isothermal" to a first approximation?
>> >> No one currently believes the Universe started out "the
>> >> size of a grapefruit", unless they also posit "c_BB >>
>> >> c_now".
>> >
>> > Note he wrote "observable Universe." Size of a grapefruit
>> > (6
>> > cm)
>> > corresponds to z=10^27.
>>
>> And you get from cm to tens of Mly in only ~300,000 years...
>> how exactly?
>
> Who thinks the size of the Universe at z=1000 is "tens of Mly?"
> That isn't what standard BB theory says.
Tens of thousdands. My leaky memory again. Sorry. This makes
it less of a problem.
>> > Let's put in some numbers. The critical density today is
>> > about
>> > 5E-6 protons cm^-2, and baryon density is about 4% of this.
>> > So at z=1000, the baryon density was about 200 protons
>> > cm^-3. The Thomson scattering cross section is 6.7E-25
>> > cm^2, so optical depth 1 was 7E21 cm or about 1E4 light
>> > years, not tens of millions.
> (George: I don't see any typos. Cross section is an area.)
>
>> The CMB spectrum follows the blackbody curve to within
>> about 1 part in 10^5 which means the source must be a
>> thin shell.
>> <END QUOTE>
>
> Yes; that's just what the calculation above says: 1E4 light
> years in
> a Universe of size about 4E5 light years.
Which is not an issue for my ingrained Newton. ;>)
>> You have to posit an opaque medium, to say that we
>> cannot see before/through it. That is the standard
>> interpretation.
>
> Indeed. As the calculation above shows, the optical depth
> should be about 40. This doesn't assume any new physics,
> just a straightforward extrapolation back in time. If you want
> to avoid the medium being optically thick at that epoch, you
> have to show why this extrapolation is wrong.
Simple. There was no medium. Coalescence had already occurred.
The CMBR is the light history of the Universe that contains ours,
written on our Big Bang. Not in disagreement with Kruskal
coordinates as a solution to black holes.
>> Now, look at the event horizon form the *inside*. I am
>> proposing
>> that it would look *exactly* like the CMBR,
>
> This seems a very strange idea.
Well, I am a very strange guy. I have been working on sewer
networks (and manipulation of the GIS datasets thereof) for
months now, and am growing cross-eyed. So just tsk-tsk quietly,
and know that the straight jacket will be arriving shortly.
I don't think Tom is willing to do my work for me, so can you
point out some places to look/ things to look for to answer my
question (light history impinging on a surface from all sources)?
My efforts will be sad, but there you are...
Sorry if I come off as kooky. This just "feels right".
David A. Smith
.
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