Black holes, dark matter

Ordinary stars make certain atoms and supernova explosions make heavier
atoms. Presently no one know what dark matter is or where it comes from.
How do we know it doesn't come from black holes? I realize that nothing
is supposed to be able to escape from a black hole, but they do leak
and what do we really know about what leaks out of them?
--
Ignorantly,
Allan Adler
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.

Dear Allan Adler:

"Allan Adler" wrote in message
...

Ordinary stars make certain atoms and supernova
explosions make heavier atoms. Presently no one
know what dark matter is or where it comes from.
How do we know it doesn't come from black holes?

DM was forming / congealing at the time of the CMBR. The
anomalous velocity profile of spiral galaxies does not change
with age (based on our ability to observe them). DM interacts
with all matter, as matter. It also cannot escape BH, except via
Hawking radiation. So if DM radiates from BHs, why did it
suddenly stop?

I realize that nothing is supposed to be able to
escape from a black hole, but they do leak
and what do we really know about what leaks out
of them?

If "dual to a black hole" are any indication, classical black
holes radiate lots of light.

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:

If "dual to a black hole" are any indication, classical black
holes radiate lots of light.




For a completely different answer, wherein stellar-mass Kerr-Newman
black holes make excellent candidates for the galactic dark matter,
and were in fact predicted and may have been detected in gravitational
microlensing studies, see the following.

www.amherst.edu/~rloldershaw

Click on "New Develpments" and see the top offering in the list of new
developments.

Papers #1 and #2 in the "Selected Papers" section also discuss why the
Discrete Fractal paradigm says the dark matter must be in the form of
stellar-mass black holes, and gives their exact mass spectrum.

And by the way, isolated black holes do not "radiate lots of light" !

Robert L. Oldershaw

Dear Rob:

Rob wrote:
N:dlzc D:aol T:com (dlzc) wrote:

If "dual to a black hole" are any indication, classical
black holes radiate lots of light.
....
And by the way, isolated black holes do not "radiate
lots of light" !

The OP was asking what "leaked out of black holes". Black holes have a
temperature associated with the mass they contain. Particles /
anti-particles that can be shed by black holes include photons (which
are their own anti-particle). It is expected that BH emissions are
characteristic of their temperature. The smaller they are, the hotter
they appear. The "dual to a black hole"s that I referred to were not
"stellar mass", but were the mass of two gold nucleii (so far). And
they radiated a lot of light. This has nothing to do with "isolated"
black holes, but the eventual fate of any black hole.

If you (Rob) would attribute all DM to black holes, then you have:
- a minimum size they must each be, to keep at / below CMBR
temperature.
- a vicinity swept clean of concentrations of matter, to keep from
acting as a UV source.

David A. Smith

dlzc wrote:
Dear Rob:


If you (Rob) would attribute all DM to black holes, then you have:
- a minimum size they must each be, to keep at / below CMBR
temperature.
- a vicinity swept clean of concentrations of matter, to keep from
acting as a UV source.


Ok, I think we agree that the amount of Hawking radiation from a black
hole is inversely proportional to the black hole mass. Tiny ones are
thought to produce little bursts of gamma radiation.

Stellar-mass black holes that are isolated in interstellar space on the
other hand cannot be detected individually in either the gamma ray or
X-ray bands at present, although Gev gamma ray excesses and excess
X-ray backgrounds may be due to vast populations of very faint
stellar-mass black holes.

Until the Glast mission is sent up in 2007, the only dependable way to
detect isolated stellar-mass black holes is through their gravitational
lensing effects. Several microlensing groups have detected excess
numbers of dark lenses at the masses predicted by the Discrete Fractal
Paradigm. See www.amherst.edu/~rloldershaw for details, especially the
most recent "New Development" and paper # 5 of the "Selected Papers".

Interstellar space is mostly "swept clean", in fact in terms of Atomic
Scale objects it is has near vacuum conditions, give or take the
occasional cosmic ray.

Robert L. Oldershaw

Dear Rob:

"Rob" wrote in message
ups.com...
dlzc wrote:
Dear Rob:


If you (Rob) would attribute all DM to black holes, then
you have:
- a minimum size they must each be, to keep at / below
CMBR temperature.
- a vicinity swept clean of concentrations of matter, to
keep from acting as a UV source.

Ok, I think we agree that the amount of Hawking radiation
from a black hole is inversely proportional to the black
hole mass. Tiny ones are thought to produce little bursts
of gamma radiation.

Just before they "pop" out of existence. I wonder if these are
GRBs...

Stellar-mass black holes that are isolated in interstellar
space on the other hand cannot be detected individually
in either the gamma ray or X-ray bands at present,
although Gev gamma ray excesses and excess X-ray
backgrounds may be due to vast populations of very faint
stellar-mass black holes.

Not if they are "isolated", by which I assume you mean the area
around them is swept clean of consumable material. They will
radiate at a temperature related to their mass. Stellar mass
size will be less than the CMBR, temperature-wise. So you'd need
gravitational lensing.

Until the Glast mission is sent up in 2007, the only
dependable way to detect isolated stellar-mass black
holes is through their gravitational lensing effects.

Didn't they detect one fairly recently by occultation?

Several microlensing groups have detected excess
numbers of dark lenses at the masses predicted by
the Discrete Fractal Paradigm. See
www.amherst.edu/~rloldershaw for details, especially
the most recent "New Development" and paper # 5
of the "Selected Papers".

Interstellar space is mostly "swept clean", in fact in
terms of Atomic Scale objects it is has near vacuum
conditions, give or take the occasional cosmic ray.

Actually everything is awash in locally generated and the ever
present CMBR light. But what we would need is three stellar mass
black holes for every star. And they would need to be
concentrated near the rim of spiral galaxies. They would even
need to be present in fairly large numbers near where we are.

I'll stick with MOND. Or its GR variant, that does not require
such huge amounts of Dark Matter (and then even huger amounts of
Dark Energy) to describe what we see.

David A. Smith

"Rob" writes:

N:dlzc D:aol T:com (dlzc) wrote:

If "dual to a black hole" are any indication, classical black
holes radiate lots of light.

For a completely different answer, wherein stellar-mass Kerr-Newman
black holes make excellent candidates for the galactic dark matter,
and were in fact predicted and may have been detected in gravitational
microlensing studies, see the following.
www.amherst.edu/~rloldershaw
Click on "New Develpments" and see the top offering in the list of new
developments.
Papers #1 and #2 in the "Selected Papers" section also discuss why the
Discrete Fractal paradigm says the dark matter must be in the form of
stellar-mass black holes, and gives their exact mass spectrum.


Thanks to you and dzlc for your comments in reply to my question. I just
glanced at your website and will look more carefully later. I just want to
record very briefly some free assocations from that glance.

First, I haven't heard of fractal models of the cosmos before, but it did
occur to me a few years ago when I read Ohanian and Ruffini's Gravitation
and Spacetime, 2d ed, particularly their discussion of different levels
of clustering, that there might be some kind of fractal model. I was
dissuaded from this idea when I read somewhere, maybe in the NY Times,
that it had been shown that there were no structures larger than a certain
size (I forget how big).

So, I guess one question I have is whether your fractal model says otherwise
and, if so, what the status is of the report of a known limit to the size of
large scale structures?

Second, when I was at MSRI in Berkeley, I knew a Go player named, I think,
Herb Doughty (not sure about the last name, nor whether he is still alive),
who was friends with a number of mathematicians and physicist (including,
I think, George Chew), probably because mathematicians and physicists often
like to play Go. He had some ideas about physics and had gotten mathematicians
and physicists to do some work on them. Roughly speaking, they involved the
idea that some very large finite field was the correct set of scalars for
doing physics and that, because of the fact that the multiplicative group
of a finite field is cyclic, there would be a kind of scaling periodicity
to the universe, putting the very large and the very small on the same
footing. For example, one might work with the field of integers modulo
a very large prime number.

I'm not saying that your ideas are the same as his or that I like his
ideas about using large finite fields. I was actually rather put off
by his belief that one could use finite fields in this way. But even
wrong ideas can be useful sometimes. Anyway, I'm just wondering whether
you ever heard of Herb Doughty and his ideas about physics.
--
Ignorantly,
Allan Adler
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.

N:dlzc D:aol T:com (dlzc) wrote:

Just before they "pop" out of existence. I wonder if these are
GRBs...

See www.amherst.edu/~rloldershaw :"New Developments": gamma ray bursts,
for a radical explanation in terms of stellar scale e^+ e^-
annihilation.


Not if they are "isolated", by which I assume you mean the area
around them is swept clean of consumable material. They will
radiate at a temperature related to their mass. Stellar mass
size will be less than the CMBR, temperature-wise. So you'd need
gravitational lensing.


Even in the "isolation" of interstellar space there are varying amounts
of ISM which would accrete onto some of the putative dark matter
objects.


I'll stick with MOND. Or its GR variant, that does not require
such huge amounts of Dark Matter (and then even huger amounts of
Dark Energy) to describe what we see.

Feel free. My guess that the answer to the dark matter test will lead
to a major change in our thinking by ruling out many bad ideas and
drawing attention to the one or two that get the answer right.

Robert L. Oldershaw

Allan Adler wrote:
I was
dissuaded from this idea when I read somewhere, maybe in the NY Times,
that it had been shown that there were no structures larger than a certain
size (I forget how big).

So, I guess one question I have is whether your fractal model says otherwise
and, if so, what the status is of the report of a known limit to the size of
large scale structures?

People say the darndest things about what is nearly unobservable.
Eternal Inflation, which is perhaps the leading conventional model for
"The Universe", says our whole observable universe is but a little
bubble in an infinite ocean. Probably nature's hierarchy extends well
beyond current observational limits.


wrong ideas can be useful sometimes. Anyway, I'm just wondering whether
you ever heard of Herb Doughty and his ideas about physics.


I will study your comments more when I have a chance and maybe look up
HD's work, but for now I can say that it is new to me.

Thanks for your comments. In cosmology, no questions are "ignorant".
The only thing that is ignorant is the claim that we have everything
just about figured out.

Robert L. Oldershaw

Rob wrote:
N:dlzc D:aol T:com (dlzc) wrote:

Just before they "pop" out of existence. I wonder if these are
GRBs...

See www.amherst.edu/~rloldershaw :"New Developments": gamma ray bursts,
for a radical explanation in terms of stellar scale e^+ e^-
annihilation.


Not if they are "isolated", by which I assume you mean the area
around them is swept clean of consumable material. They will
radiate at a temperature related to their mass. Stellar mass
size will be less than the CMBR, temperature-wise. So you'd need
gravitational lensing.


Even in the "isolation" of interstellar space there are varying amounts
of ISM which would accrete onto some of the putative dark matter
objects.


I'll stick with MOND. Or its GR variant, that does not require
such huge amounts of Dark Matter (and then even huger amounts of
Dark Energy) to describe what we see.

Feel free. My guess that the answer to the dark matter test will lead
to a major change in our thinking by ruling out many bad ideas and
drawing attention to the one or two that get the answer right.

Robert L. Oldershaw

Hi Rob.

I have some math that allows fractal behavior in any dimension:
http://bandtechnology.com/PolySigned
There is a primitive Mandelbrot study listed there.
I've done some other fractal experiments but high dimension data is
problematic due to its density. One day I'll port my code over to
OpenGL so that at least 3D graphics will occlude properly.

-Tim