(alpha) Dark Matter - what is it?

Billy T

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I had following idea which avoids postulating some unknown non- baryonic form several years ago (Partially built the concept into my book Dark Visitor when postulating that the "dark visitor" was a Black Hole of 2.2 solar masses, in defiance of "conventional wisdom" which states that BHs in this size range are very rare or non existent.)

I have previously posted brief explanation as to why there may be more of these few stellar mass BHs than all the stars that have ever existed, perhaps enough to be the origins of Dark Matter.

I make this thread in hopes of either persuading some that I am correct or that they persuade me that I am wrong.

If anyone is interested, I will explain:

(1) Why there may be many stellar-size BHs, (despite the conventional view there are few, if any).
(2) Why they are not individually* detectable. Except if one passes near our solar system, and then only by their gravitational perturbation of planet orbits. (Not detectable, even when close, by "gravitational lensing" of more distant stars).
(3) Why they are not detected by a “micro- quasar” effect (radiative interaction with in-falling “cosmic gas”) when passing near solar system.
(4) More about the misunderstood, but possible prior detection of one passing by the solar system in the late 1920s. (Neptune’s unexplained perturbation that lead to the discovery of Pluto.)
(5) Why any objections you may raise against these stellar-size BHs being very abundant are not fatal to that possibility.
(6) How other alternatives are less likely. (However, BH dark matter may be made from complimentary pairs of magnetic monopoles. - I consider this a reasonable possibility as it also explains why magnetic monopoles are not found. I.e. this may very likely be part of the dark mater, which would clump also to make the "lumpiness" seen.)

I see no reason to expand on any of these six until some one ask me to do so. In case I do get more than one request, please order by the above numbers the relative level of your interest. E.g. say “I vote we do in order 2, 1, 4” or something like that.

I would appreciate it if someone would comment on the “baryonic or not” nature of a BH that was made entirely from Baryons (and charge neutralizing leptons also, of course.) I think it very unlikely that any BH can become significantly charged as charged virtual pairs produced just outside the EH will be selectively captured to keep the external E field low. Thus, + & - charges “eaten” in growing a BH must be nearly equal.

My plan is to wait a few days see if there is interest, and then, take the issues of most interest, one at a time, until most everyone active here thinks that horse number “X” is dead then start to beat up on an new numbered colt until we kill it too, etc. rather than mingle all six tighter at the same time.

Add more questions any time and I will add them to the list of colts yet to kill.
Also feel free to ignore all six and tell why you think dark matter must be non-baryonic etc. if you like.
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*Collectively they may have been detected and constitute the much, if not all, of the “lumpiness” observed in dark matter. (“Hot dark matter” can not provide this “lumpiness,” but may be very important in the average in view of the neutrino’s probably small mass.)
 
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(1) Why there may be many stellar-size BHs,
(2) Why they are not individually* detectable.
(6) How other alternatives are less likely.

I am interested to hear about these---specifically, (1) and (2) are not true if one accepts that black holes were formed early in the universe and decay by Hawking radiation. If there exists some mechanisms for creating these black holes, you can solve (1) (but you'd still have to explain the mechanism). I do not think you can get away from (2), unless you can show me some null results from an experiment. Finally, (6) is very debateable as most extensions to the Standard Model of particle physics include DM candidates.
 
Ben:

What is your take on the magnetic-monopole-pair hypothesis of Billy T as potential DM candidates? I have a particular interest in that subject, as known to Billy T.

I've read some accounts where monopoles are hypothesized to have a rest mass on the order of 1E23 eV! Quite large, being the most massive particles in physics by many orders of magnitude.

Walter
 
What is your take on the magnetic-monopole-pair hypothesis of Billy T as potential DM candidates? I have a particular interest in that subject, as known to Billy T.

I am not familiar with this, but supposedly it is a dipole made of oppositely charged magnetic monopoles? Either way I don't know if it matters---the way I understand it, monopoles would have been produced before inflation, and so would be so diluted that we probably wouldn't have any in our Hubble Volume.

I've read some accounts where monopoles are hypothesized to have a rest mass on the order of 1E23 eV! Quite large, being the most massive particles in physics by many orders of magnitude.

I am not familiar with the literature on the subject, but what this seems to say is that monopoles get mass at the String or Planck scale. This is a common thing for physicists to argue, that some (possibly undesirable) particle gets such a large mass, and cannot contribute to low energy phenomenology.

Perhaps Billy (and you) can explain this in a bit more detail?
 
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I am interested to hear about these---specifically, (1) and (2) are not true if one accepts that black holes were formed early in the universe and decay by Hawking radiation.

One would have to postulate some dynamical way of generating solar mass black holes at least as fast as they decay. Further, that production channel should be unobservable. But the only way that I know to make a black hole is a collapsing star, which is definitely observable.
 
I always thought dark matter was just matter which did not emit visible light and was therefore invisible to astronomers :confused:

Why was this simple theory (presumably) discarded long ago?
 
One would have to postulate some dynamical way of generating solar mass black holes at least as fast as they decay. Further, that production channel should be unobservable. But the only way that I know to make a black hole is a collapsing star, which is definitely observable.
I do not have the necessary information readily available, but seem to recall that even "moon sized" primordial BHs could survive against Hawking radiative decay until now. Perhaps the higher density of the early universe is supplying them mass to grow at greater rate they are losing it via HR.

However, I will explain the mechanism I think caused the huge (250+/- 50 solar masses typically) first stars (Gen. III) to be factories of several dozen "few solar mass" BHs soon. - After it is clear that the first item of my six to discuss is #1. (I want to wait to give others, like Physic Monkey, Trilairian, James R, etc. a chance to vote if interested in any of the six.)

In the mean time I suggest we do consider the magnetic monopole BHs.

I do not know that they are formed only during the inflation period. What evidence is there for this POV (other than it too could account for why none have been found)?

I am far from knowledgeable in this area, but have sort of a dynamic quasi-equilibrium concept of matter being formed out of energy after the inflation. I.e. a lot of local oscillation back and forth in a cubic millimeter (which might now be a cubic kilometer) between matter and energy densities, but with a steady on average "tilt towards matter" as time passes. Is this a reasonable POV? (for ref: 1)

I also think the more massive particles to condense out ot the energy were the leaders in the sense that they ceased oscillation back into energy first. Thus I think that there were many primordial magnetic monopoles before there was much other matter in a very small universe shortly after the end of the inflation. Is this a reasonable POV? (for ref: 2)

I do not have any idea as to what the typical separation between an N and S monopole was, but bet it was sufficiently small that they were attracted to each other (by inverse square law force, not inverse cube, of course) Is this a reasonable POV? (for ref: 3)

As the "fell towards each other" it is highly unlikely their impact parameter was exactly zero and I think probable that quantum considerations were important. I.e. I think they captured each other in quantized orbits before they got to an aggregate density that converted them into monopole BHs, mBHs. Is this a reasonable POV? (for ref: 4)

I suspect that HR began to play some role before they became mBHs. I.e. something like HR was the mechanism by which they cascaded down thru the energy levels (ever larger energy gaps, just as in hydrogn atom) of the "Magnetic Dipole Atom," MDA. Is this a reasonable POV? (for ref: 5)

Perhaps I should not call this HR but Magnetic Dipole Atom Radiation. For all I know there are "selection rules" etc for permitted Magnetic Dipole Atom Radiation just as there are for EM radiation from atoms. I think the quantum discriptions of the Magnetic Dipole Atom Radiation must be quite similar to that of atomic hydrogen as both are two oppositely "charged" particles in each other's inverse square fields. I am not sure but suspect that the Magnetic Dipole Atom Radiation is just ordinary EM waves/photons, but acknowledge that it may be some propigating energy transport we know nothing about. Does any of this seem a reasonable POV? (for ref: 6)

Now for the main point:

I suspect that the energy gap between the ground state and the first excited level of the Magnetic Dipole Atom, MDA, is very large compared to twice the rest mass of even a proton / anti-proton vacuum polarization pair, (because the monopoles are so massive.) Thus the mechanism HR is forbidden (or energy conservation must be broken long term) as the excited Magnetic Dipole Atom, MDA, can not make 3% of a quantized transition if that 3% is what equals the ~1000MeV rest mass of the anti-proton, which escapes while its "proton mate" is gravitational bound in some complex (at least in this classical POV) three-body orbit by the gravity of the massive N & S monopoles. Does any of this seem a reasonable POV? (for ref: 7)

SUMMARY thus far: It seems at least plausible to me that quantum effects can stabilized the Magnetic Dipole Atom, MDA, again HR as "fractional transitions" between quantized levels may be required.

So now how could a Magnetic Dipole Atom, MDA, transition to a mBH? Well I would first drag out some sort of "tunneling effect." You may not know that all of the ground states of the hydrogen like atoms are "S states" (in spectroscopic notation) or l = 0 (zero angular momentum) states in standard quantum notation. I imagine that the same is true of the Magnetic Dipole Atom, MDA in its ground state. In a classical POV they are oscillating thru each other not around their common CoM (or mid point, if the N and S monopoles are equally massive, as I assume they are.) Thus in time short compared to the current age of the universe, I think they could become mBHs, if their density is large enough. Perhaps they do so on after only a few "passes thru each other" in their l = 0 "orbit." I.e. in much less than a nanosecond after the Magnetic Dipole Atom Radiation, which dropped the excited Magnetic Dipole Atom, MDA, into its ground state as it leaves the Magnetic Dipole Atom, MDA. Does any of this seem a reasonable POV? (for ref: 8)

I will stop here and wait for your reactions and to give others a chance to indicate what they vote we discuss first. - See first post for six choices.
 
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I always thought dark matter was just matter which did not emit visible light...Why was this simple theory (presumably) discarded long ago?
It has not been discarded. In fact I am trying to defend a version of this POV, but if you go to Wikipedia (dark matter) you will learn most believe that dark mater is some unknown exotic new form of matter (except the "hot dark matter people" but I am sure they can only be partially correct as that matter (probably neutrinos now that it is almost sure they have mass) can not explain the observed "lumpiness" of dark matter in space.

After coming up to speed, jump in with your POV too.
 
Billy---It is hard to read your posts because you use so many abreviations. I tend to forget what they mean between the time that I read your post and the time that I respond to it (~2 minutes), so could you please try to use less abreviations for my sake (at least)?

A few responses.

I am not familiar with monopoles or other instantons (or topological defects, if you like), but it was my impression that they were the result of some spontaneous symmetry breaking. Because we have not seen them yet, they cannot be associated with the electroweak symmetry breaking, which we probe at FermiLab. It is more likely that they were produced in some early epoch of the universe, before inflation, during the breaking of some unified theory, say SU(5) or SO(10). Inflation caused the density of magnetic monopoles in our Hubble volume to be approximately zero, which is why we don't see any monopoles today.

It seems as if you have assumed the existence of magnetic monopoles (and that there were two of them, N and S)---I think that this is an invalid assumption.

I do not have any idea as to what the typical separation between an N and S monopole was, but bet it was sufficiently small that they were attracted to each other (by inverse square law force, not inverse cube, of course) Is this a reasonable POV?

So you are talking about setting up a bound state of two oppositely charged magnetic monopoles? This should be find, and would look probably like a hydrogen atom with different constants in the formula. There will be an S state (as well as p, d, f, g, ... states). But this point is a bit moot if you can't show me why there should be monopoles at all, or why we shouldn't have seen them yet.

Thus in time short compared to the current age of the universe, I think they could become mBHs, if their density is large enough.

So the bound state decays into a black hole? Hmm. The monopoles would have to be pretty massive. Is this what oyu ar proposing?

About the Lunar mass black holes. I found this paper on the www.arXiv.org...

http://arxiv.org/PS_cache/astro-ph/pdf/0203/0203520.pdf

I will quote briefly the introduction (PBH = primordial black hole, CDM = cold dark matter):

From Phys.Lett.B535:11-16,2002...

PBHs were produced in the very early universe. PBHs generated before 10^-23 s, corresponding to masses M < M_L ≈ 5×10^14 g, have already evaporatedby the present day due to Hawking radiation. PBHs with masses bigger than M_L could, however, constitute a significant fraction, or even all, of the CDM. Unfortunately this possibility, though attractive, cannot be implemented with scale-free perturbations because they would lead to a negligible rate of PBH formation.

Basically, they are investigating the possibility of using primordial black holes to act as dark matter, of mass 10^14 grams or so. The problem is with this statement

Unfortunately this possibility, though attractive, cannot be implemented with scale-free perturbations because they would lead to a negligible rate of PBH formation.

The WMAP experiment has told us that the cosmic microwave background gives us exactly scale-free perturbations. (This is talking about the background temperature fluctuations in the universe. WMAP has put very stringent limits on these things.) This would seem to rule out the proposal in this paper, unless I am misunderstanding something.
 
I always thought dark matter was just matter which did not emit visible light and was therefore invisible to astronomers

Why was this simple theory (presumably) discarded long ago?

This is how we define dark matter, but it tells us nothing of what it actually is. We would like to be able to explain it, because 25% of the universe is made of it---compared to ordinary matter, which comprises less than 3% of the universe.
 
Billy---It is hard to read your posts because you use so many abreviations.
Ok, I have edited post 7 to totally eliminate MDAR (replaced it with "Magnetic Dipole Atom Radiation") and inserted "Magnetic Dipole Atom" just prior to "MDA" everwhere MDA occurs.

Now, in addition to the reasonable common use of "EM radiation" instead of Electro-Magnetic radiation" I have only BH (for Black Hole) and mBH (for magnetic dipole Black Hole) and HR (for Hawking Radiation). Hope that helps.

I will now read your links and then respond to other parts of your post.
 
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To BenThe Man, et.al.
(Comments on your ref and citation of others)

Correct me if I error, but your reference does not seem to say anything about when magnetic monopoles formed or their mass.

It gives a model of the PBH (primordial black hole) formed during the inflation, but recognized that a broader mass range may form later. I.e. last part of the abstract is:

“…We show that in this model the relevant PBH mass is constrained to lie in the range 5x10^15 g < M < 10^21 g. This is much less than the mass range coming from the QCD phase transition, ...”{See later bold also. I.e. I do not base my claims on the formation of PBHs during inflation. I do not even need to use the much greater production at the QCD era, but will hold this discussion of how dozens of BHs may come from each GenIII star for a few days more.}

Also stated in article is: “PBHs generated before 10^−23 s, corresponding to masses M < ≈ 5x10^14 g, have already evaporated by the present day due to Hawking radiation. PBHs with masses bigger than 1M⊙ {solar mass} could, however, constitute a significant fraction, or even all, of the CDM. Unfortunately this possibility, though attractive, cannot be implemented with scale-free perturbations {which do not occur during inflation?, but makes no comment on later formation of PBHs} because they would lead to a negligible rate of PBH formation.”

The mass of the moon is 7x10^25 g. thus it seems my memory was correct, and very conservative. I.e. a PBH much smaller than the moon would still be here, because Hawking Radiation rapidly decreases with mass - basically because the gradient at the event horizon is decreasing as mass increases, at least linearly, I think.

I also searched arxiv.org/astro on “Black Hole size distribution” and got 76 hits, then read the abstracts of about 15.

The authors of http://arxiv.org/PS_cache/hep-ph/pdf/0106/0106187 try to show that there are enough PBH with approximately 100 solar masses {that is ~2x10^35 g} to be the seeds of the galaxies. The thing most interesting to me is that their model predict many order of magnitude larger number of “moon-sized” PBHs. - See especially their fig 2 on page 927.
Thus there may be a million times more “few solar mass” PBHs than there are galaxies. If these PBHs tend to clump inside, or oscillate thru, the galaxies, then there are thousands in our galaxy and one may have passed close enough to our solar system to have gravitational interacted weakly with Neptune in the late 1920s (item 4 of post 1).

Also supporting this POV is:
http://arxiv.org/astro-ph/0504034
Where in left column of page 6 you can read:
“One possibility is that PBHs with a mass of around 1M⊙ (one solar mass) could have formed at the quark-hadron phase transition at 10^−5s because of a temporary softening of the equation of state then [43]. Such PBHs would naturally have the sort of mass required to explain the MACHO microlensing results [84]. If the QCD phase transition is assumed to be 1st order, then hydrodynamical calculations show that the value of δ required for PBH formation is indeed reduced below the value which pertains in the radiation case [85]. This means that PBH formation will be strongly enhanced at the QCD epoch, with the mass distribution peaking at around the horizon mass then. One of the interesting implications of these scenarios is the possible existence of a halo population of binary black holes.[116] With a full halo of such objects, there could be a huge number of binaries inside 50 kpc …”

I also found interesting:
(http://arxiv.org/abs/gr-qc/0306066)
as it may be useful when I respond to item 1 of post 1. I do not understand much of it. It seems to be a model of either the entire universe or the smallest possible Plank volume! I may need internal temperature and density functions when discussing item 1, so I record this reference here. Do you think the given temperature and density functions may reflect anything about the variation of temperature and density in the central regions of a large Gen.III star?

The abstract was:

“The holostar is an exact spherically symmetric solution to the field equations of general relativity with anisotropic interior pressure. Its properties are similar to a black hole. It has an internal temperature inverse proportional to the square root of the radial coordinate value, from which the Hawking temperature law follows. The number of particles within any concentric region of the holostar's interior is proportional to the proper area of its boundary. The holostar-metric is static throughout the whole space-time. There are no trapped surfaces, no singularity and no event horizon. Information is not lost. The weak and strong energy conditions are fulfilled everywhere, except for a Planck-size region at the center. Geodesic motion of massive particles in a large holostar is similar to what is observed in the universe today: A material observer moving geodesically experiences an isotropic outward directed Hubble-flow of massive particles. The total matter-density decreases over proper time by an inverse square law. The local Hubble radius increases linearly over time. Geodesic motion of photons preserves the Planck-distribution. The local radiation temperature decreases over time by an inverse square law. The current radial position r of an observer can be determined by measurements of the total local mass-density, the local radiation temperature or the local Hubble-flow. The values of r determined from the CBMR-temperature, the Hubble constant and the total mass-density of the universe are equal within an error of 15 percent to the radius of the observable universe.
The holographic solution also admits microscopic self-gravitating objects with a surface area of roughly the Planck-area and zero gravitating mass.”
 
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DM, it a figment of some humans retarded imagination.

Instead of correcting their wrong theories, they chose to make the wrong into right.
 
...Because we have not seen them {BHs} yet, they cannot be associated with the electroweak symmetry breaking, which we probe at FermiLab....It seems as if you have assumed the existence of magnetic monopoles (and that there were two of them, N and S)---I think that this is an invalid assumption.
If they did ever exist, do you have problems with both N & S being created in equal numbers? I am really only assuming they were created, as predicted by the accepted theory of matter formation, not that they exist today. (Perhaps now all are pairwise in BHs. Their mutual attraction is extremely large compared to the gravitational force that assembled the stars etc. and equally “long range” in slow fall off.) I think many physicist more knowledgeable than me are puzzled by fact(?)* that we do not find magnetic monopoles, only electric monopoles. Magnetic monopoles easily fit into Maxwell's equations, in fact make them "more beautiful" as they are then more symmetric.

If the monopole is a massive as most theoreticians believe, would FermiLab experiment have been able to create (or even observe some "resonance" due to) one? Is failure to find them in this era the only reason you think they may never have existed, despite the theoretical prediction that they should have been created as energy “condensed” into matter?

In my book, one chapter discusses many different things the "dark visitor" that may have perturbed Neptune's orbit in late 1920s could be, in addition to mBHs and gives my guess on the probability of each. Few solar mass BHs are, IMHO, the most probable cause of that unexplained perturbation, which was observed / measured by dozens of astronomers.
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*Perhaps one has been seen. An unexplained current step was once seen in a super-conducting ring's current of just the correct magnitude to have been a magnetic monopole passing thru the ring. Unfortunately, I no longer have the reference. There have been dozens of attempts to pull them out of various material, usually iron meteorites that have wandered thru space, with intense magnetic gradients. One attempt was near you (if you work at FermiLab). It used oysters because these filter feeders process huge volumes of water. That was the reason for inspecting oysters given on the grant proposal, but I think fact that oysters taste good and are expensive in Chicago, was at least a minor factor.:D I think this was at U of Chicago, but may have been Argonne or FermiLabs.

SUMMARY: I think, with many others, that it strange we do not see magnetic monopoles but need not assume they ever existed to believe that there are more few solar mass BHs than all the stars that have every existed.

So you are talking about setting up a bound state of two oppositely charged magnetic monopoles?…So the bound state decays into a black hole? Hmm. The monopoles would have to be pretty massive. Is this what you are proposing?
Yes, to facilitate them staying near each other long enough to merge into mBH. Sort of like “muonium atom” facilitates the mutual annihilation of a muon and it anti-muon.
They are very massive. I have never seen any suggested mass less than 10^16eV. At least 10^22eV seems likely, but I can only repeat what I have read. (way over my head). I am anxiously waiting for the results now starting to come in from the > 1000 detectors*, covering many square miles, to collect cosmic ray data in pampas of Argentina. - Possibly the very high energy cosmic rays are magnetic monopoles. If this is the case, no primary ray will be found with energy more than the monopole’s rest mass and we will then know what it is experimentally.
Yes. - Some have even proposed that each is dense enough to become a mBH and explained there current absence that way.
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*Large Cerinkoff water tanks, GPS used with their known locations to precisely time the showers. Computers then determine what apart of sky the primary came thru and several dozen optical telescopes get air glow data etc to learn its energy. (Or something like that in the pitch-black, uninhabited pampas.) By far the most careful study of cosmic rays ever attempted, with more and better data soon than all of prior investigations combined!
 
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My chem teacher told us that for dark matters to exist there has to be half polar matters, and there is no evidence of such. Just a thought
 
What if Dark Matter was ice crystals or dropplets? That would add up very fast as to weight and as to where water comes from. Oh well, just a thought.
 
My chem teacher told us that for dark matters to exist there has to be half polar matters, and there is no evidence of such. ...
I don't know what "half polar matters" are, but it does not mater. Like most people, my newspaper boy also does not think Dark Mattrer exists. Clearly the truth is determined by democratic vote and thus Dark Matter is nonsense. :rolleyes:
 
What if Dark Matter was ice crystals or dropplets? ...
ice sublimes in a vacuum. Ice cristals need some body (a coment usually) to be stable on (and even that is not long term). Individual ones in space would not last a year.
 
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