(urth) Problematic element in chronology - Red Giants

[Gerry Quinn]

From: "Jeff Wilson" <jwilson at io.com>
> On 5/29/2011 7:48 PM, Gerry Quinn wrote:

>> I don't think the issue of small black holes matters to BotNS - the
>> black hole described is absorbtive, and thus large enough to have a low
>> temperature. In the context of black holes, there's actually not much
>> margin between the temperature of a stellar interior and that of outer
>> space. They are either colder or hotter than either, and those that
>> persist are certainly colder.
>
> Where is it described?

Standard theory (you can find it in Wikipedia etc.) has the temperature of a 
black hole inversely proportional to its mass.  A solar mass black hole has 
a temperature of about a ten millionth of a degree.  An earth-mass black 
hole has a temperature of a fiftieth of a degree.  A black hole massing a 
million tons would have a temperature of 10^14 K.

Ignoring mass transfer, a black hole with a mass of a million million tons 
would be in thermal equilibrium with the Sun's core, at a temperature of 
10^8 K.  Such a black hole would have an event horizon only one micron in 
diameter, so it wouldn't find it too easy to swallow a lot of matter.

Multiply the mass by another factor of 200000, and the black hole is finally 
black, with a temperature of 500 K, and a diameter of 20 cm.

Any larger black hole would be colder and larger, both in proportion to its 
mass.  I think we are to assume that the black hole in the Sun is cold and 
reasonably large.  In truth it's hard to imagine that it would have the 
effects described in BotNS; I assume Wolfe is winging it.

- Gerry Quinn