Re: Chandra and black hole abundance

From: Spike Jones (
Date: Fri Jan 14 2000 - 23:24:52 MST

Damien Broderick wrote:

> My newspaper tells me very briefly that the latest X-ray telescope data
> suggest`at least' 100 million black holes in the galaxy. That's not very
> many, not for the dark matter problem (but every little helps).

If I understand it correctly, the larger a black hole, the harder it is to
observe. Since the radiation it emits is a direct function of the surface
area of the event horizon but the frequency is inversely proportional
to the square of the area, a large black hole would emit less total
radiation than a small one. If so, then the ones observed and reported
in today's paper are the smaller ones? Its been several years since I
have read Hawkings books. Perhaps Amara Graps can help us?

The thing that worries me more than the dearth of black holes and
other dark matter is the evidence that the expansion of the universe
is accelerating. That is bad news for Tipplerites. {8-[ spike

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