Question about the origin of Dark Matter.?

Question

First, let me say that I have absolutely no formal education in Physics or Quantum Mechanics, beyond what I've read and researched for fun.

I'll keep my question simple:

Is it possible that dark matter is the product of matter reduced to a singularity within a black hole?

I'm honestly looking for why it isn't possible, so I can stop thinking about it. :)

Answer 1

Seeing as we don't really have much of an idea what dark matter is, it's pretty hard to say anything about where it comes from.



If something gets incorporated into a black hole, it either stays there, or comes out via Hawking radiation.



Assuming it stayed there, it would have to be some kind of miniature black hole. We can detect black holes as big as the sun or bigger. That mass is accounted for. No miniature black hole has ever been found. It is theoretically possible for a black hole of any size to exist, but there is no conception of how a low-mass black hole would form. Matter resists being compacted dense enough to make a small black hole; the gravity of a massive star is needed to overcome that resistance. We would expect not to find any miniature black holes in the same way as we expect not to find any stars the mass of Earth.



Hawking radiation is based on virtual production of a particle and its antiparticle, for example an electron and a positron. Particles and antiparticles have opposite charge, which sort of implies they ought to have SOME charge. The issue of whether uncharged particles such as neutrinos can have an antiparticle is unresolved. Dark matter clearly has no charge, or it would interact with light. So it is somewhat uncertain that dark matter has an antiparticle. If not, it could not be produced by Hawking radiation. If so, perhaps it could.



But I doubt that all the Hawking radiation ever produced is enough to account for the amount of dark matter. So while black holes could be A source of dark matter (and even that is a very wild guess), I don't think they could be THE source. I'd guess it's most likely dark matter was just created in the Big Bang like most everything else, and has been around since then.

Answer 2

"Question about the origin of Dark Matter.?"



When calibrating a factor "total normal mass in that spot" / "luminosity" at the center of a spiral galaxy, we get a need for more mass as we get further from the center. Rather than assuming it was a stupid calibration error, they assumed it was Dark Matter, meaning "unexpected or exotic" matter.



"First, let me say that I have absolutely no formal education in Physics or Quantum Mechanics, beyond what I've read and researched for fun."



Quantum Mechanics does NOT predict anything in the exotic matter realm, so that would not really have helped you.



"I'll keep my question simple:



"Is it possible that dark matter is the product of matter reduced to a singularity within a black hole?"



The candidates that we have discovered more and more of are:

- ionized normal matter, which simply does not interact with visible light in a specular way;

- rogue planets and brown dwarves;

- stars with complete photospheres, unlike the hotter region at the center of a spiral galaxy;

- stars hidden by dust clouds that attenuate and dim a star's output;

- neutrinos (which are pretty much accounted form separately);

- and yes some black holes.



"I'm honestly looking for why it isn't possible, so I can stop thinking about it. :) "



There is certainly "unknown matter". I sincerely doubt it is "exotic matter". But it cannot *all* be black holes... the distribution is very uniform, and is distributed above and below the galactic plane, so it should periodically interact with other stars in a visible way. The closest black hole we can see (yes, with only 100+ years of good observation) is 1500 light years away...

Answer 3

The closest theory I'm aware of to what you're suggesting (assuming that I understand you correctly) is the proposal of Pisin Chen (and collaborators) found here:



http://arxiv.org/abs/astro-ph/0305025



The basic idea is that the so-called generalized uncertainty principle implies that primordial black holes will not completely evaporate, implying that primordial black hole remnants might survive until the current era, and these remnants are a possible candidate for dark matter. Not the most popular candidate, but it is a possibility.



EDIT: Also, I've noticed that in quite a few answers there are statements along the lines of "no, because black holes aren't enough to explain the amount of mass we detected." Consequently, I think it's worth pointing out that we don't actually know that this 26.8% of the mass-energy of the (known) universe all arises from a single type of object. Even if it were the case that black holes cannot account for the amount of additional mass we observe (which it's not), that doesn't mean that they are not responsible for a portion of the dark matter content of the universe.

Answer 4

Most of us are willing to admit that we don't have a clue what Dark matter is (other than it does interact through gravity AND it does NOT interact through electrodynamic fields).

Most of us are willing to admit that we don't understand what goes on "inside" the event horizon of a black hole.



However,



Based on the definitions of what these terms DO mean, the answer to your question is no.



Either nothing comes out of a black hole (classical definition) or some form of KNOWN particle is radiated from the event horizon - or just slightly outside - according to Stephen Hawking's idea about evaporation (quantum mechanics are involved).



Dark matter seems to be something with mass (real mass, as opposed to "imaginary" mass). Dark matter seems to behave as if its mass was connected to the Higgs Field and was causing a gravity-type interaction with other matter, even if the Dark matter seems undetectable using our usual electromagnetic "devices" (telescopes, radio-telescopes, X-ray or gamma telescopes, etc.). Therefore Dark Matter, by definition, should NOT be able to escape from the inside of a black hole, any more than, let's say, a jar of peanut butter that has fallen past the event horizon.



A "singularity" is a mathematical object that belongs to the domain (input values) of an equation. In the "easy" solution - to a non-rotating, non-charged black hole - the singularity has the shape of a single point in the domain (the 4 dimensional space made up of 3 spatial dimensions and time) in the metric used in Relativity.



However, since "non rotating" is a relative term, we expect that there is no such thing, in reality, as a non-rotating black hole.



The solution to a rotating, non-charged black hole, is a circle (the circumference of that circle) = a 1-dimension object wrapped onto itself around a 2nd dimension. It was worked out by a mathematician called Roy Kerr.



I will not get into what the singularity looks like if the black hole actually has an electrical charge. Ask Roy Kerr and Ezra Newman.



To say that an object "becomes a singularity" makes no more sense than saying that a mineral deposit in a mine, becomes a "depth"

Answer 5

First: there is solid evidence that galaxies do not behave as we expect them to based on the matter we can observe.

The conclusion from that is that there is some type of mass that changes the distribution of mass (hence changes the gravitational field) for all galaxies from what we expect. I think this is a weak conclusion; other theories have been proposed, but none so far, fit the evidence as well. What we "know" (quote unquote) about this dark matter is that it does not interact with normal matter except gravitationally. If you know anything about black holes, you know that they effect EVERYTHING they get near. This is not what we see, so either we need to change our theories of how microscopic black holes behave (which would be radically different and contradictory to our current understanding) or dismiss the idea that they are the "dark matter" we are currently looking for. Do not misunderstand: "dark matter" as the term is used classically means all mass that we can not observe. It includes black holes, dark stars, comets, dust clouds and wandering planets - everything that we don't see. As I said, we've concluded that the large majority of this "stuff" can not be accounted for as being composed of these things - so it must be "something else". The alternative you suggest would require "new physics" to explain why black holes don't behave the way we expect (and the way a lot of observations have confirmed that the large ones DO behave).

It would be quite unscientific to do this UNLESS your theory explained something that is now without explanation while at the same time is consistent with all the other things we know about physics. I'd be surprised if your idea hasn't been considered in depth many many times and then discarded as not being promising. A good example is string theory. It was originally proposed (don't quote me on this, its been a while since I read up on it) as a way to explain the weak force (?) but didn't work. It was dug up again and seems promising to explain gravity and quantum mechanics but has yet to deliver a testable prediction. Lots of people are working on it, but so far its been fruitless. A Scientific Theory must result in testable predictions. String Theory and oddly behaving microblack holes do not. Until they do, there is nothing preventing people from working on them, but neither will be taken seriously until we see some results. Requiring a "special and never before seen" new Law of Physics in order to get your miniblack hole idea to work is a non-starter unless it leads to something extraordinarily useful (or until every other possibility has been discarded).

Extraordinary claims require extraordinary evidence. Occams razor says make as few assumptions as possible to fully explain the evidence.

Einstein said:"Make everything as simple as possible, but not simpler."

Adding new rules would not be simple.

Answer 6

I think you're asking, are there more black holes floating around than we're aware of? Once matter falls into a black hole, it's joined to the singularity; nothing can get out (well, Hawking radiation can...) but, the "mass" part of it will be trapped for a very long time.



Individual bits of matter dense enough to be a singularity will 'evaporate' quite quickly (It's one of the things they were worried about with the LHC - the production of micro-black holes... the smaller the black hole, the quicker they 'dissolve.')



If a black hole is large enough to exist for long enough to affect the speed of rotation of galaxies, I am guessing their signatures (X-rays, optical effects) would be noticed as well. Since we don't see many, small singularities floating around - I believe the answer lies elsewhere.

Answer 7

Dark matter does not behave like black holes, so no. Not even hypothetically.



No one is really sure what dark matter is. But we know of its existence by what it does. And that behavior is different from black holes. Dark matter behaves like an invisible scaffold holding the structure of galaxies (like their spiral shape) together in a way that would not happen without dark matter. The distribution of mass in our galaxy is more homogenous thanks to dark matter, else most of it would be concentrated in the core.



Dark matter hardly interacts with ordinary matter at all. I've heard a few hypothesis about DM, none of which can be verified. The most interesting one is that DM represents ordinary matter in a nearby parallel universe where only a few things like gravity seep through. Again, nothing to back this up yet.

Answer 8

It could be possible the thing about dark matter is we cant see it, and we can't really test it so any theory is out there, I don't know if it would be a black hole, just because we have a much better understand of black holes, I would think if it was we would have a much better understanding because where we can't know or test dark matter we can observe black holes.

Answer 9

The only problem with your idea is the phrase "reduced to a singularity within a black hole'. A black hole is always and only a singularity. No black hole has non-zero size. They differ in mass, but not in size (although, because they do differ in mass, the differ in size of accretion disk and event horizon - but the black hole itself is always the same, zero, size).



There are scientists who belieeve that dark mass might consist of large numbers of low-mass black holes, but the ides is yet to be tested. It continues to be the case that we really have no idea what dark matter is - let alone dark energy, by the way.

Answer 10

The reason we suspect dark matter exists is because of the rotation rate of galaxies. Basically, when you measure the speed of stars on the edges of galaxies and then estimate the amount of material in the galaxy (by measuring the brightness of the stuff you can see), you find that they're moving too fast! There doesn't appear to be enough bright stuff to give enough mass to create enough of a gravitational pull to keep those stars from flying off into space. Hence the idea of 'dark matter'.



When astronomers did the maths, they got a bit of a surprise - you need there to be more than 5 times as much dark matter as bright matter. If there is 'dark matter' then we know it can't be made up of stuff we're familiar with - if it was, we'd see it absorbing light or giving off light or heating as it was accelerated around stars, etc. It has to be something a bit exotic, like neutralinos or other theoretical particles.



Now, why can't it be black holes? Well, what that'd mean is that more than 5 times the entire mass of the visible galaxy would have to be compressed into black holes. That'd require almost every dead star in our galaxy to have formed a black hole, which just doesn't sit with what we know about black holes. If that mass was confined in one black hole then we'd definitely have noticed it by now because it'd distort space time so much that we'd see light bending around it (gravitational lensing). If it's lots of smaller black holes then we'd have noticed many of them too, since they'd be sucking gas off stars or because of gravitational lensing.



So black holes can't explain the sheer amount of mass that dark matter contributes to a galaxy. The only thing that would explain it is lots and lots and lots of particles, each one of which is a bit of a fatty.

Answer 11

It could be possible, but there is absolutely no evidence for such a thing. And there is a LOT of good theory, based on observed facts, that says that such is thing is not true.



In science, we stick to fact-based stuff. Observations first, then try to explain them based on what we already know. Right now, "dark matter" has very few observations -- not enough to explain what it is, much less where it comes from.

Answer 12

No, Dark matter lenses light at the galactic scale - it is spread out.

\it seems to be massed above and below galaxies towards the core.

There is no hypothesis or theory to explain dark matter, we see an effect nd assume a single cause.

Answer 13

All we know is that there is more matter than we see. It isn't possible to hypothesize on it's creation yet.



However, your idea of it being the product of matter being reduced by a black hole is gibberish.

Answer 14

I think most of that dark matter came from my Grandmother. She used candles only, and her house is full of dark matter:-)