"been teaching literature for over 35 years"

Gerry Quinn · 09 Sep 2013, 09:58 · from 2013-September.txt.gz

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From: gerry at bindweed.com (Gerry Quinn)
Date: Mon, 9 Sep 2013 10:58:20 +0100
Subject: (urth) "been teaching literature for over 35 years"
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From: Jerry Friedman
[..]
>>>  On 9/8/2013 9:19 AM, Gerry Quinn wrote:

>>>>  It's hard to see scientifically how a white hole cancelling a black
>>>>  hole would do that - but seemingly it does.  If so, one might argue
>>>>  for the the theory that the black hole in the Sun somehow stopped
>>>>  plate tectonics. Perhaps what is in the Sun is not quite a black hole
>>>>  as we think of it. [For that matter, I think an actual black hole in
>>>>  the Sun would cause it to heat up - but even if I am correct, story
>>>>  clearly must trump science in this regard.]

> I think that a black hole, even as currently understood, would cool the 
> sun
>  if it were significantly cooler than the temperature of the interior of 
> the sun.
> You can have some fun at <http://xaonon.dyndns.org/hawking/>.

The Hawking temperature of a black hole in the sun doesn't matter.  What 
matters is the energy emission from infalling matter as it accelerates and 
is compressed before reaching the Schwarzschild radius.  Presumably it will 
form an accretion disk in the heart of the sun, but this will only happen 
when the radiation from the disk is sufficient to balance the hydrostatic 
pressure in a 'bubble' at the core of the sun.  Which is pretty high 
pressure!

If the black hole is not parked in the centre but orbiting at some distance, 
it will cause a net increase in radiation.  But over time 'friction' (in the 
most general sense) and mass increase will bring it to the centre.

So that's the first thing - the black hole is radiating pretty hard due to 
infalling matter.  Actually it seems arguable that it might radiate about as 
much as was radiated from the same zone (the zone of balance) as was 
radiating before, in which case its direct influence on the sun's 
temperature would be slight considering the black hole alone.

However, the radiation from the black hole comes from already 'burned' solar 
matter.  As it absorbs matter from the heart of the sun, more hydrogen-rich 
fuel will fall towards the centre of the sun.  Surely this would be expected 
to release some extra energy due to nuclear fusion?

In the second place, as it absorbs the sun's core matter it should cause the 
sun to effectively age.  Stars like the sun get hotter as they age, as the 
'burn' zone where fusion takes place expands in radius.  So for this reason, 
too, I would expect a black hole to cause the sun to heat up.

I'm sure - Wolfe's lack of detail wins again - one could find an argument 
for how cooling might occur.  But on first principles, I'd expect a black 
hole dropped into the sun to have a warming effect.

- Gerry Quinn

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