Re: "Mysterious quasar casts doubt on black holes"

From: Dani Eder (
Date: Sat Jul 29 2006 - 07:53:36 MDT

--- "kevin.osborne" <> wrote:
> any physicists/cosmologists on the list keen to
> comment on the impact
> of this? And maybe give the layreader a grounding on
> what a MECO is,
> and also maybe what effect this discovery (if
> confirmed) might have on
> quantum physics and or string theory?

I have a physics degree but have not been active in
the field for many years. Reading a paper on the
MECO, my understanding goes like this:

A collapsing object's magnetic field energy density
eventually gets high enough to cause electron-positron
pair creation out of the quantum vacuum.

You then get a plasma of electrons/positrons and
the high energy photons they annihilate back to
that stabilizes itself from the photon pressure.
The stabilization happens deep in a gravity well,
but short of an event horizon.

The plasma is optically thick, meaning most of the
photons scatter before escaping. The ones on the
surface that do get out are highly (Z~10^8)
so energy leaks out of the object very slowly
(timescale of 10^10 years).

Black holes can't have a magnetic field, and these
things do. These things also radiate a little,
but more than the Hawking radiation of a black hole,
so there are observational differences that can
let you tell them apart.

On your last question, this type of object uses
quantum effects to predict that black holes don't
develop. Relativity is a non-quantum theory that
predicts black holes when escape velocity > speed
of light. But we know that quantum effects exist
and have to be taken into account when describing
the universe.

I dont know what, if any relation this idea would
have to other new ideas like string theory or
spactime dimensions>4.


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