Did Primordial Black Holes evaporate?

nightbat

New research published in the IOP's journal of Classical and Quantum Gravity shows that primordial black holes did not die out - they formed stable gravitational bound states called Holeums in the aftermath of the Big Bang - which form haloes around galaxies today, and are an important constituent of dark matter.

An isolated black hole is subject to the evaporation of its mass due to the Hawking radiation caused by the vacuum fluctuations in its vicinity. This would seem to rule out the possibility of formation of
bound states of primordial black holes. There are two conditions which need to be satisfied for a black hole to evaporate due to Hawking radiation:

(a) The black hole should be isolated.
(b) It sould be in field-free space.

Primordial (microscopic) black holes were produced in vast quantities in the immediate aftermath of the Big Bang. The conditions prevalent in that era were very different from those present today.

(1) Matter was highly compressed - all matter was closely packed together, and expanding at a high rate. This violates the condition of isolation of black holes necessary for the Hawking radiation.
(2) Near the unification temperature, of the order of 10 exp 16 GeV, all the four fundamental interactions of nature are expected to have the same strength. In particular, the gravitational interaction would have a strength far greater than it has now. This violates another condition for the Hawking radiation, namely, a field-free space. This also means that the rate of gravitational interactions among the black holes would correspondingly be higher - and they would form stable, bound states.

In other words, extremely high number density, vastly stronger gravity and an enormously larger rate of interactions are likely to lead to the formation of stable bound states of primordial black holes.

This is analogous to what happened with neutrons - although a free neutron decays, neutrons in the nucleosynthesis era of the early universe finding themselves in high number densities and subject to the strong interaction formed stable nuclei and never decay except those neutrons that are in heavy nuclei containing a large number of protons.

These stable bound states of PBHs would still be around and would form a significant constituent of dark matter.

This discovery should give LIGO - the newest Gravitational wave detector - something to look for!

wolram

http://aanda.u-strasbg.fr:2002/artic...33/aa2933.html

In most cosmological models, primordial black holes ( PBH) should have formed in the early Universe. Their Hawking evaporation into particles could eventually lead to the formation of antideuterium nuclei. This paper is devoted to a first computation of this antideuteron flux. The production of these antinuclei is studied with a simple coalescence scheme, and their propagation in the Galaxy is treated with a well-constrained diffusion model. We compare the resulting primary flux to the secondary background, due to the spallation of protons on the interstellar matter. Antideuterons are shown to be a very sensitive probe for primordial black holes in our Galaxy. The next generation of experiments should allow investigators to significantly improve the current upper limit, nor even provide the first evidence of the existence of evaporating black holes.

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i thought this artical might be of interest, i know nothing about the
subject.

nightbat

It is an interesting article...they theorize that the Hawking evaporation of PBHs will eventually lead to the formation of antideuterium nuclei and do a first computation of the antideuteron flux.

The research I mentioned proposes that PBHs formed stable gravitational bound states called Holeums post-Big Bang - which do not evaporate. These holeums have only the gravitational interaction, and therefore form large haloes around galaxies - and are an important component of the elusive Dark Matter. Some classes of holeums also contribute significantly to dark energy. Holeums also are a major source of cosmic rays - which arise due to their vacuum ionization. The papers can be found online at:

http://arxiv.org/ftp/gr-qc/papers/0308/0308054.pdf
http://arxiv.org/ftp/gr-qc/papers/0309/0309044.pdf

wolram

http://arxiv.org/abs/gr-qc/0309044

The principle of nuclear democracy is invoked to prove the formation of stable quantized gravitational bound states of primordial black holes called Holeums. The latter come in four varieties: ordinary Holeums H, Black Holeums BH, Hyper Holeums HH and the massless Lux Holeums LH.These Holeums are invisible because the gravitational radiation emitted by their quantum transitions is undetectable now.

i always thought HAWKING RADIATION nonintuitive.
but that is not unique, gravity is the most confusing
subject. a hole new family of "eums", is going to add
to the confusion.

Labguy

Interesting stuff and reading. But (if there, I missed it), what is the likelyhood that "numerous" PBH's in close proximity quickly merged, so while the small ones, absent the conditions in first post, "would have" evaporated / decayed, these new and larger merged PBH's would (1) be more massive and tend to decay more slowly, and (2) be more massive and thereby attract even more at a greater rate for more "merging". I suppose that millions of PBH's could have very quickly become a few massive BH's with little tendency to have S_radius energy strong enough to do anything other than any other massive BH we might find today. .....(?)Ideas?

wolram

quote.

Holeums also are a major source of cosmic rays - which arise due to their vacuum ionization.

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http://heasarc.gsfc.nasa.gov/docs/as...ce/cosmic.html

Using data from the Japanese/U.S. X-ray astronomical satellite ASCA, physicists have found what they term "the first strong observational evidence" for the production of these particles in the shock wave of a supernova remnant, the expanding fireball produced by the explosion of a star.

http://science.nasa.gov/newhome/head...#anchor1684358

The origin of cosmic rays remains a long-standing mystery in contemporary astrophysics. Scientists suspect that cosmic rays - essentially atomic particles that bombard the earth at nearly light speed - are hurled through space to such great speeds by the shock waves of exploding stars, called supernovae.

http://focus.aps.org/story/v5/st16

Prime suspect. New estimates of extragalactic magnetic fields suggest that the mysterious source for the highest energy cosmic rays may be M87 (imaged here in radio wavelengths), an active galactic nucleus powered by a billion-Sun-sized black hole.
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i can find no mention of "holeums", in the search for the origines of
cosmic rays, the sites posted posit a less exotic source.

nightbat

Wolram - There is no mention - so far - of holeums because it is a brand new theory. I would deem supernova shock waves and galactic black holes to be exotic sources of cosmic rays, rather than holeums! They can never account for the amount of cosmic rays which bombard the earth every day. Holeums make much more sense. The holeum haloes around galaxies are a continuous background source of cosmic rays. The cosmic rays are emitted when holeums undergo pressure ionization. This theory provides plausible explanations for the mysteries of Dark Matter, Dark Energy, and the origin of Cosmic Rays in a simple and straightforward manner.

This whole new family of "eums" (H, BH, HH, LH) has not added to the "confusion", it has provided a simple, straightforward and elegant solution to these long standing and perplexing questions. I agree that this theory is very new and hard to digest, but it does make sense.

Labguy - post big bang, innumerable primordial black holes were formed due to gravitational inhomogeneties. They were all in very close proximity to each other. They did not "merge", they formed stable gravitational bound states, akin to the Hydrogen atom. These stable bound states are not black holes, they occupy space just like ordinary matter, and interact only gravitationally. They are therefore a new form of matter. As they are not black holes, they do not decay by the Hawking radiation and therefore must still be persent today, as haloes around galaxies. The presence of massive, unseen gravitating haloes around galaxies has recently been confirmed by experimental observations.

wolram

The presence of massive, unseen gravitating haloes around galaxies has recently been confirmed by experimental observations.

this is interesting, do you have a link?

nightbat

Here are a few:

http://spaceflightnow.com/news/n0308/11halo/
http://arxiv.org/abs/astro-ph/0206126
http://aanda.u-strasbg.fr:2002/artic...92/aa1092.html
http://www.strw.leidenuniv.nl/information/normgal.html
http://xxx.lanl.gov/abs/astro-ph/9501068
http://www.star.bris.ac.uk/nam/abs_galaxy_dynamics.html
http://www.blackwell-synergy.com/lin...3.06680.x/abs/

You will find many more on the internet.

Nereid

The holeum ideas referenced in this thread are certainly interesting. However, IMHO, the proponents have rather a lot more work to do on likely observational effects - and testing those against astronomical archives - before this will become truly exciting.
The paper is ambiguous here; taken literally, it is incorrect (there is, in fact, direct observational evidence that at least some of these objects are sources of cosmic rays). The context is about extremely high energy cosmic rays (>10²⁰eV), and in that sense it is correct; there is no direct evidence. However, it is disingenuous; so few cosmic rays of such high energy have been observed that the data is consistent with ANY source. No it's not, and neither does the paper reference any work to show the contrary.

Labguy

Nightbat
You stated above that "Labguy - post big bang, innumerable primordial black holes were formed due to gravitational inhomogeneties. They were all in very close proximity to each other.". Then you state that "These stable bound states are not black holes, they occupy space just like ordinary matter, and interact only gravitationally.".

If "innumerable" BH's formed, but "stable bound states are not black holes, they occupy space just like ordinary matter", then what is the description/fate of the millions of PBH's?

Last I read from Hawking was that the PBH's were very small and would quickly decay so as not to exist today. I don't doubt your (probably more current) information, but would like to read a reference or two on this specific subject. Can you direct me to a site or two on this specific subject (theory?)?

Thanks;
Labguy

EDIT: I first posted this as a quote from Nereid. It was NOT Nereid, it was nightbat. Sorry for the mistake.

nightbat

Labguy,

The fate of the innumerable PBHs is that they formed stable gravitational bound states and became holeums. These holeums have only one interaction - the gravitational one. They therefore clump together in holeum clouds on the periphery of other matter. These holeum clouds are the dark matter haloes observed around galaxies.

Here are a couple of links for Hawking radiation and PBHs:

http://www.rdrop.com/users/green/school/primordi.htm
http://www.rdrop.com/users/green/school/radiatin.htm
http://www.voidspace.org.uk/science/n.shtml
(Someone put the entire "A Brief History of Time" on their website)

You won't find much on the Holeum theory yet on the internet, except the papers:

http://arxiv.org/ftp/gr-qc/papers/0308/0308054.pdf
http://arxiv.org/ftp/gr-qc/papers/0309/0309044.pdf

Nereid,

There is at least some evidence of cosmic rays from galactic halos:
http://www.atnf.csiro.au/people/Mich...em/pop/cr.html
You'll find many more on the internet.

I'm sure there are a few ambiguities and such things, but I'm also sure you'll agree that the physics behind the papers makes sense. I agree - there's a lot of work still to be done on this. In fact, this seems to be just the beginning of the theory.

Nereid

LOL! The link you gave has some nice examples of observations of gaseous halos and shells around some galaxies; no argument there! The page goes on to say, more or less, that where there's synchrotron radiation, there must be cosmic rays (CRs). I was kinda hoping for something more direct, similar to the unequivocal detection of some Seyferts/AGNs and SNRs as sources of high energy CRs. It's certainly interesting. Let's see what specific predictions the proponents make about what might be observed. I would expect there would be quite clear implications for the immediate neighbourhood - from the Earth's core out to ~10pc, for example.

Leo

Primordial Balck Holes did not evaporate:

see subject: Dark Matter as primordial Black Holes etc.

Leo.

nightbat

Nereid,

I agree - we need some specific predictions about what might be observed. We can forget about the gravitataional wave spectrum for the time being, as LIGO is not yet operational, and we don't know how successful it will be. But they have provided some specific predictions about the other points as well: the origin of ultra-high energy cosmic rays from the holeum halos around galaxies (by a process akin to pressure ionization), and the massless "Lux Holeums" which carry a very large amount of energy (Dark Energy?). And that is the really interesting part.

Labguy

I agree 100%. I have been directed to two papers on "Holeums" and have to consider this as emerging, new theory. What can we expect to find as observational evidence? Neutron stars were predicted, and as Pulsars too, long before the 1966 evidence was collected.

In several posts, I have seen the Holeum papers taken as proven fact, and quoted as gospel. I can read too, and don't yet place 100% of my faith in the theories found in these (rather new) papers.

Labguy

Nereid

Peronally, I'd hold out more hope of LIGO or LISA finding a signature than UHE CRs; the former is at least up and running and the latter will be very sensitive; UHE CRs are easy enough to detect, but there are so few of them that it'll take years of continuous data collection to say anything sensible about their origin. I didn't understand the "Lux Holeums"; but the proponents really need to do more work on what's likely to be detected/detectable; after all, interesting theories/ideas are many; well characterised, testable predictions are much more interesting!