Physicists Argue That Black Holes From the Big Bang Could Be the Dark Matter (quantamagazine.org) 85
Long-time Slashdot reader fahrbot-bot quotes Quanta magazine:
It was an old idea of Stephen Hawking's: Unseen "primordial" black holes might be the hidden dark matter. It fell out of favor for decades, but a new series of studies has shown how the theory can work...
Their very blackness makes it hard to estimate how many black holes inhabit the cosmos and how big they are. So it was a genuine surprise when the first gravitational waves thrummed through detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015. Previously, the largest star-size black holes had topped out at around 20 times the mass of the sun. These new ones were about 30 solar masses each — not inconceivable, but odd. Moreover, once LIGO turned on and immediately started hearing these sorts of objects merge with each other, astrophysicists realized that there must be more black holes lurking out there than they had thought. Maybe a lot more.
The discovery of these strange specimens breathed new life into an old idea — one that had, in recent years, been relegated to the fringe. We know that dying stars can make black holes. But perhaps black holes were also born during the Big Bang itself. A hidden population of such "primordial" black holes could conceivably constitute dark matter, a hidden thumb on the cosmic scale...
Following a flurry of recent papers, the primordial black hole idea appears to have come back to life. In one of the latest, published last week in the Journal of Cosmology and Astroparticle Physics, Karsten Jedamzik, a cosmologist at the University of Montpellier, showed how a large population of primordial black holes could result in collisions that perfectly match what LIGO observes. "If his results are correct — and it seems to be a careful calculation he's done — that would put the last nail in the coffin of our own calculation," said Ali-Haïmoud, who has continued to play with the primordial black hole idea in subsequent papers too. "It would mean that in fact they could be all the dark matter."
"It's exciting," said Christian Byrnes, a cosmologist at the University of Sussex who helped inspire some of Jedamzik's arguments. "He's gone further than anyone has gone before...." And with every subsequent observing run, LIGO has increased its sensitivity, allowing it to eventually either find such small black holes or set strict limits on how many can exist. "This is not one of these stories like string theory, where in a decade or three decades we might still be discussing if it's correct," Byrnes said.
Their very blackness makes it hard to estimate how many black holes inhabit the cosmos and how big they are. So it was a genuine surprise when the first gravitational waves thrummed through detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015. Previously, the largest star-size black holes had topped out at around 20 times the mass of the sun. These new ones were about 30 solar masses each — not inconceivable, but odd. Moreover, once LIGO turned on and immediately started hearing these sorts of objects merge with each other, astrophysicists realized that there must be more black holes lurking out there than they had thought. Maybe a lot more.
The discovery of these strange specimens breathed new life into an old idea — one that had, in recent years, been relegated to the fringe. We know that dying stars can make black holes. But perhaps black holes were also born during the Big Bang itself. A hidden population of such "primordial" black holes could conceivably constitute dark matter, a hidden thumb on the cosmic scale...
Following a flurry of recent papers, the primordial black hole idea appears to have come back to life. In one of the latest, published last week in the Journal of Cosmology and Astroparticle Physics, Karsten Jedamzik, a cosmologist at the University of Montpellier, showed how a large population of primordial black holes could result in collisions that perfectly match what LIGO observes. "If his results are correct — and it seems to be a careful calculation he's done — that would put the last nail in the coffin of our own calculation," said Ali-Haïmoud, who has continued to play with the primordial black hole idea in subsequent papers too. "It would mean that in fact they could be all the dark matter."
"It's exciting," said Christian Byrnes, a cosmologist at the University of Sussex who helped inspire some of Jedamzik's arguments. "He's gone further than anyone has gone before...." And with every subsequent observing run, LIGO has increased its sensitivity, allowing it to eventually either find such small black holes or set strict limits on how many can exist. "This is not one of these stories like string theory, where in a decade or three decades we might still be discussing if it's correct," Byrnes said.
Interesting turn around. (Score:5, Interesting)
Its been somewhat of the consensus in modern physics that blackholes simply where not common enough to account for the missing matter, and that if it was we'd see a lot more lensing going on. It seemed like that idea was dead in the water
However these new finding are compelling. I'd caution that not all the objections have necessarily been satisfied yet, we are a *long* way from truly marking Dark Matter as a solved issue. And seriously, wheres the lensing? But it certainly adds a pretty big clue into the mix.
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Primordial black holes can be tiny. If the vast majority of them are small enough, there'd be no noticeable lensing.
Re:Interesting turn around. (Score:4, Interesting)
The argument is given the amount of time since the big bang they would have merged to be a size where lensing should be visible. Also LIGO would detect those mergers more frequently than those happening within galaxy's. So they still need to explain why neither seems to true if their theory about DM being black holes is correct.
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So, for the same reason that we haven't seen all stars merge into a single black hole, it seems un
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> What would cause black holes to merge
Simply gravity. Remember that dark matter is supposed to be 5 times more common than the normal visible matter (stars) we can see. Normal matter was uniformly distributed as well but that didn't stop star and galaxy formation. The same would apply to primordial black hole mergers. You are absolutely right about not seeing all stars merged into a single black hole. There is an open question how the supermassive black holes at the centre of every galaxy came to be. Th
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Simply gravity. Remember that dark matter is supposed to be 5 times more common than the normal visible matter (stars) we can see. Normal matter was uniformly distributed as well but that didn't stop star and galaxy formation. The same would apply to primordial black hole mergers.
Not so. Gravity alone would keep them orbiting around each other to eternity. Yes it's an n-body problem so chaos will ultimately send some within a "capturing radius" (distances which leak enough energy to gravitational waves to overcome their relative velocities), but this is a one in a trillion kind of occurrence, because these capturing radii are tiny for stellar-mass black holes. No stars are expected to hit each other in a Milky Way / Andromeda merger, for the same reason.
The equivalence between dens
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Does that make sense though? As much as any other hypothesis about dark matter. Actually it is a little more so.
What would cause black holes to merge? Gravity. Just watch the old galaxies screensaver for Linux. For a rudimentary simulation on how gravity affects large objects.
Why would their respective orbits, which would be very large, retrograde? I would recommend High school newtonian physics. Gravitational pulls other objects large and small create a degree of resistance periods of billions of years th
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If these are stellar-mass objects distributed analogously to stars, they would be as likely to merge as stars are. Actually less since they're more compact. How often do we see stars merging? Black holes orbiting each other at a safe distance should happily do so for the known age of the universe. The authors propose that interactions between black holes have made their orbits more circular over time (and there's been a lot of time!), which would make catastrophic close encounters very rare.
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I would recommend High school newtonian physics.
If a High school book in Newtonian Physics indicated to you that objects in freefall would naturally have degrading orbits, you should probably re-read that book.
Gravitational pulls other objects large and small create a degree of resistance periods of billions of years things change.
I don't really know what this sentence is trying to say.
There's no more reason to think black holes would be bouncing into each other willy nilly than there is to think the end state of all orbital systems is to fall into their center of mass. It simply does not work that way.
When black holes merge, it's because they got *really* close to each o
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Re:Interesting turn around. (Score:4, Informative)
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How many of those small black holes would there be, in order to be consistent with the "clouds" of dark matter associated with (most) galaxies? What are the odds that we would have seen stars having encounters with them? If they fall into orbits with regular stars, we should see that: either a large motion by the visible star, or small enough that the black hole devours the visible star.
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The reason for asking is that (as I understand it) the former does not ask us to reconsider our understanding of the universe, since it is based on observed phenomena, whereas the latter has yet to be observed.
But happy to be corrected...
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But why can those be tiny and not newly formed black holes? Are they pre-inflation? Does Hawking radiation not affect these black holes?
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There is no mechanism to form a tiny blackhole in the current universe. you have to go way back to the weird physics of the early universe.
And either Hawking radiation doesn't affect them, but that seems unlikely. Or they have just enough mass to still be around, something above 1e11 kg (a large asteroid like 433 Eros is on the order of 6e15 kg). But also it was ruled out last year [sciencedaily.com] that primordial blackholes could be smaller than 0.1 mm (mass 1e22 kg)
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Interesting, thanks. I would have thought that the end of inflation would eliminate odd stuff like this as well, but perhaps not. I will have to read more about it.
Understanding Needed (Score:2)
Primordial black holes can be tiny. If the vast majority of them are small enough, there'd be no noticeable lensing.
Initially, true but then these huge clouds of tiny black holes would merge to form larger ones and we would have a population of various sizes today which would be detectable. LIGO's data suggest the opposite though: there seem to be more high mass BHs than anyone suspected. These might be able to explain Dark Matter while also being few enough in number to make lensing events rare - but I'm not an expert on MACHO searches which is where these limits will come from.
However, if that is the case - and it
Re:Interesting turn around. (Score:5, Insightful)
However these new finding are compelling. I'd caution that not all the objections have necessarily been satisfied yet, we are a *long* way from truly marking Dark Matter as a solved issue. And seriously, wheres the lensing? But it certainly adds a pretty big clue into the mix.
Observations show the gravitational effect localized around galaxies, and for colliding ones, adjusting relative to the galaxies centers.
There would need to be enough primordial black holes in orbit around each galaxy such their gravity wells form a nearly complete sphere.
It would seem to mean the view of the universe outside of our galaxy is already mangled with a lensing effect, so they have a lot more math to work out what the universe really would look like after taking that into account.
We've seen the effect on stars and gas and other matter in the centers of galaxies when the blackholes at their centers merge. This new idea would need to explain why all the gas surrounding a galaxy is excluded from doing the same when trillions of primordial blackholes merge during the same events.
A somewhat worse consequence would be intergalactic travel and exchange of matter would be impossible. Matter couldn't traverse the halo of primordial black holes without hitting an event horizon of at least one of them.
Of course that is another inconsistency needing to be explained due to never observing it during galaxy collisions, but it would mean whatever matter is in a galaxy is all you ever can get, none of it can leave and no more can come in.
Re:Interesting turn around. (Score:4, Interesting)
Black holes, whatever size they might have, can release the energy as gravitational waves, and thus they would also form aggregation discs like visible matter. So we need an explanation why the primordial black holes keep those halos we see from gravitational lenses.
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Primordial black holes may be a good answer for the missing mass, but they're not a good answer for the *observed* mass distribution.
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We've seen the effect on stars and gas and other matter in the centers of galaxies when the blackholes at their centers merge. This new idea would need to explain why all the gas surrounding a galaxy is excluded from doing the same when trillions of primordial blackholes merge during the same events.
When galaxies merge, the stars don't collide, because there is so much space between them. Black holes are collapsed stars, so they would have even more space in between them, and not merge either.
But you touch on a good point: when galaxies collide, they move a lot of interstellar gas around. Some of this should end up accreted by the black holes, lighting them up like a Christmas tree. Since we never observed this, it is doubtful that they are there.
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Dark matter (invisible gravity) appears to be evenly distributed throughout the galaxies and their halos.
There is, of course, traditional matter all out there as well.
In fact, there's so much more invisible matter, that probabilities inform that there should be interaction that we can detect if the "hidden" gravity sources were tiny black holes.
Black holes, as we know them, primordal or tiny, still scream to high heaven when they collide with normal matter.
We don't see that.
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You grasp the situation well.
We are pretty well informed about the chaos at the center of galaxies.
What surprised us is that the velocities of stars near the center of galaxies are comparable to the velocities of stars on the periphery.
That makes no sense at all.
We know, for instance, that Pluto takes about 248 years to orbit the Sun and we can, by formula, calculate the orbitals of all the other planets using Kepler's math.
That fails us in those galaxies where an invisible gravity is evenly distributed fro
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I agree 100%.
We did chase this idea long ago for reasons.
I'm going back to that soon to see what has changed about those prior objections.
There's a shit load of dark matter (invisible gravity) in the galactic objects and gravitational lensing is present, but normal matter accounts for that.
It's too convenient, to me, that dark matter distributes itself evenly about the center of galazies, apparently unaffected by the gravitational well of a supermassive black hole at the center.
The black holes are certainly
Most Plausible Explanation, I hope. (Score:5, Insightful)
Okay this now sounds like the most plausible explanation for Dark Matter that I have heard. All the other ones to date sound far fetched and cooky with a lot of mental and mathematical gymnastics required to make them work.
I hope to see more work done on this hypothesis to see if it is in fact the case.
The results from LIGO and associated experiments is the most exciting and interesting stuff that I have seen in astrophysics.
Good job physicists. Looking forward to much more.
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Well the fact that the universe, or anything, exists is in itself kooky. Dark matter is mildly cooky in comparison. Compared to a universe existing, it's less far fetched that particles which can only interact via gravity can exist, though one has to wonder how such a particle can keep itself together -- although you could ask that of an electron.
Re: Most Plausible Explanation, I hope. (Score:5, Insightful)
All the electron responses so far have been negative -
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All the electron responses so far have been negative -
The protons are positive about this :-)
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Groups of neutrons, however, are taking a neutral approach while the individuals tend towards positivity after a short while.
Re: Most Plausible Explanation, I hope. (Score:1)
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Compared to a universe existing, it's less far fetched that particles which can only interact via gravity can exist, though one has to wonder how such a particle can keep itself together -- although you could ask that of an electron.
People keep forgetting these sorts of particles already exist. Neutrinos barely interact via the strong force, and being neutral, not at all electromagnetically. If their strong force interaction was a few orders of magnitude less, we might not even be able to detect them at all. So when you say kooky, nature says "Hold my boson condensate!" .
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>though one has to wonder how such a particle can keep itself together -- although you could ask that of an electron.
The answer could well be the same - according to current theory there's nothing holding an electron together, because an electron isn't made of anything. It's a fundamental, indivisible particle that exists simultaneously at all points in the universe (though _almost_ all of it typically falls within a very small radius)
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An electron is certainly made of something.
It has a shitload of properties that we can experience directly with a bobby pin and a wall socket.
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That's electricity - you can't directly experience a single electron any more than you can see a single photon - only the statistical properties of large enough quantities of them to stimulate your vastly larger sensory receptors.
They do have intrinsic properties - position, velocity, mass, charge, and spin, but that doesn't mean they're made of other things, it just means they have properties. The Standard Model of elementary particles is quite likely one of the most heavily tested theories ever, and is w
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https://en.wikipedia.org/wiki/... [wikipedia.org]
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... "energy" doesn't exist as a separate thing.
Bullshit.
E=MC
You've read some, but not enough. Try working out some of the problems on the side.
That's what I had to do to get past the point that you're at.
You've got a decent start, but it needs work.
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That should be E=MC^2, but that's just the "exchange rate" between matter and energy, it doesn't tell you what form the energy is in . And energy MUST have a form, there's no such thing as just "energy" floating in space as an independent thing.
If you annihilate matter to create energy, that energy will manifest as either photons or other elementary particles "spontaneously" coming into existence, potentially at high speed (for the particles with mass, kinetic energy being one of the forms that energy can
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No.
Mass is frozen energy.
The two are different forms of each other.
There is no creation or destruction, no losses in converting from one phase to the other.
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Nope - check my other post - mass is a *property* of energy, regardless of its form. Matter had mass because matter *is* energy.
Look, it's easy to prove me wrong - provide an example of energy that's NOT in the form of either elementary particles or their properties.
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Crud, replied in the wrong spot - please forgive the dupe:
A much better explanation: The Real Meaning of E=mc https://www.youtube.com/watch [youtube.com]?... [youtube.com]
Basically, a more conceptually informative way of writing Einstein's equation is m=E/c^2: *everything* is energy, while mass is a property that energy has. Doesn't matter if you've got two matter and antimatter baseballs, or have collided them to create high energy photons, then convert the photons to heat to drive your steam engine and stored it in a g
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A much better explanation: The Real Meaning of E=mc https://www.youtube.com/watch?... [youtube.com]
Basically, the more informative way of writing Einstein's equation is m=E/c^2: *everything* is energy, while mass is a property that energy has. Doesn't matter if you've got two matter and antimatter baseballs, or have collided them to create high energy photons, then convert the photons to heat to drive your steam engine and stored it in a giant flywheel - the amount of energy remains the same throughout (it cannot be cre
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Well the fact that the universe, or anything, exists is in itself kooky.
That's "kooky" has been sufficiently explained by the anthropic principle.
Dark Matter, so far, hasn't been sufficiently explained by anything except a couple equations that lead to the conclusion that, essentially, something must be out there.
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You are arguing that because you've been dealt the perfect poker hand, your next hand should be pretty good. Where's the correlation?
No, it's either part of the extreme kookiness or it's independent.
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It doesn't sound that plausible to me. Dark matter makes up significant halos around most galaxies, so we're talking about a lot of primordial black holes, and surely there must have been countless mergers over the last 13 billion years, and we'd have lensing events in galactic halos.
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Why? It's generally believed that almost all binary stars both form from the same pre-stellar gas cloud - kind of like identical twins forming from the same fertilized gamete. The reason being that two-body orbital capture is basically impossible, and it's wildly improbable that 3+ stars would interact in a manner that would leave two of them gravitationally bound to each other.
Which would pretty much require that any companion star to a binary black-hole had to form in orbit - and the radiation pressure
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Oops:
>require that any binary companion star to a _ black-hole had to form in orbit
Re: Most Plausible Explanation, I hope. (Score:1)
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Between LIGO and the Event Horizon Telescope, we stand a chance of working some of these problems out.
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Quantized Inertia is actually a pretty decent explanation for much of the stuff Dark Matter is invoked to explain - particularly galactic rotation curves, which it correctly predicts based purely on the distribution of visible matter. It's basically the idea that the Unruh effect and Rindler horizons (both confirmed phenomena associated with accelerating bodies) interact in a manner similar to the Casimir effect - where two plates placed very close to each other get pushed together by the greater pressure
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I agree this sounds plausible. But I still hold out hope for something kooky. If it is just scattered black holes, then there's nothing new for us to play with tech-wise.
Large Impact on Particle Physics (Score:2)
Okay this now sounds like the most plausible explanation for Dark Matter that I have heard.
It has been around for quite a while but there are still potential issues with it although LIGO's data is likely to start to address these one way or the other. From a particle physics perspective though if BHs are confirmed as the likely source of Dark Matter it will have a huge impact on the field.
There are lots of underground experiments performing direct Dark Matter searches based on the assumption that Dark Matter is a subatomic particle that interacts through weak or even Higgs-like interactions.
How many (Score:2)
OK, how many of them are surmised to exist in the Milky Way .. specifically in our region of the milky way. If one were near the solar system it would be embarrassing if we didn't detect that.
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You should look up the search for Planet Nine in our own solar system. One of the plausible theories is that it is a black hole orbiting our sun out passed Pluto. It's not embarrassing that we would miss it -- it's black on a black background, and the only info we have to go on is the jiggling of Kupier Belt objects.
I don't know about you..... (Score:1)
......but I find the idea of enormous numbers of hidden black holes floating around out there... disturbing.
I know space is big, and I do think it's a long way to the chemist, but whoa.... I kinda don't like to think we (as in Earth or the Sun) would run into one some day....
Kinda a bit freaked out now.....
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I would think the black holes are also moving outward as well. Isn't the whole universe expanding from it's origin still? Seems unlikely our solar system would overtake a black hole. Suppose anything is possible though.
At one point I think we even thought there could be a black hole in the farthest reaches of our solar system, a planet X if you will. I don't think we ever found anything and then we demoted Pluto so now we're down to 8 planets.
It's still fun to read about despite the fact nothing we discover
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There's not really any reason a collision would be any more likely than with another star. There's not really any difference between a black hole and a "normal" non-luminous object until you get close enough to collide with the normal object. And as I recall, most dark-matter solutions require than most of the dark matter be out beyond the visible rim of the galaxy.
not inconceivable, but odd (Score:5, Funny)
You keep using that word, I don't think it means what you think it means.
Predict or Die (Score:2)
Yes, yes it is. Unless you can predict something, this idea is dead. It's nice to retrofit an idea to fit the observed data but unless it has predictive qualities, "primordial" black holes will go the way of String Theory. And there have been plenty of "theories" that "fit" the data but turned out to not be true. Ptolemaic system anyone...
Re: Predict or Die (Score:5, Informative)
Re:Predict or Die (Score:4, Insightful)
Yes, yes it is.
Actually, I think I agree with the guy from the article that we won't be discussing if this is correct in a decade or three decades, because you can make predictions from this. Most of the obvious predictions seem to be trivially disproven. So we won't be discussing it in a decade because the theory will probably be categorically disproven. It seems pretty likely that if 90% of the invisible matter in the universe was made of fairly evenly distributed black holes, we would have noticed due to all the reasons people have been pointing out. The main problem seems to be that black holes are massive collections of very highly concentrated matter. So we should see gravitational lensing from them. A loose cloud of particles that only interact with gravity wouldn't cause noticeable wobbles in objects that it passes by because it would be pulling in all directions pretty much evenly, but a black hole will definitely cause a wobble. Also, if there are that many black holes, collisions between them and other objects should be more common. Not just stars and planets, but nebulae. We should be able to see them interacting with dust and gas, etc. As Stephen Hawking put it "black holes ain't as black as they are painted". Someone pointed out that maybe, by "primordial black holes" they meant relatively tiny black holes that are well below the size we normally think of as the lowest possible size a black hole can be. The problem is that if the universe were 90% made up of small black holes, we would notice them raining down on the sun and gas giants and even our own upper atmosphere. I suppose it would depend on how big they actually were. If they were large enough for collisions to be infrequent, then we would be seeing them destroying entire planets during collisions, or we would see a lot more comet activity from the Oort cloud being stirred up. I can't imagine that interaction of normal matter with any kind of black hole anywhere from the size of a grain of sand on up would lead to anything other than a massive release of energy.
Now, I suppose it's possible that there are all these black holes out there and there's some special principle that keeps them from intersecting with all the normal matter all the time. We could call it dark energy type 2, I suppose. Overall, it just seems like there are too many holes and they can't be patched with anything that makes more sense than other current theories.
Now, if the LIGO results do indicate that black hole collisions are more common than thought, there could be other things in play leading to that. One possibility is that it's been speculated that many black holes may actually be binary systems or triples, etc. where multiple black holes orbit each other very closely. Binary stars are, after all much more common than single stars, so it wouldn't be that surprising if it's the same for black holes. That means that such black holes may eventually merge, leading to a higher number of collisions than expected. It's not clear to me if the results they're talking about could be from little black holes falling into the big central black holes at the heart of galaxies, but maybe that's the cause. Other than that, this is complete speculation, but we typically imagine a star falling into a black hole being ripped apart by it and having it's material siphoned off as it gets closer and closer, but could the gravity of a black hole trigger a big enough star that's being sucked in to actually collapse into a second black hole before it's pulled in, thus leading to two black holes colliding? That one may be far-fetched, but I'm not quite to the bottom of the barrel yet. Another possibility is that there are just unknown phenomena out there that might cause the gravity waves that they're interpreting as black hole collisions. Even further down in the barrel, could there be something like a dark matter black hole if the gravity-only style of otherwise intangible dark matter actually exists? Not that known black holes probably aren't presuma
Dark matter, or matter with no energy. (Score:2)
The theory that dying stars create black holes makes sense then if those stars emitted all their remaining energy in their final life as a star; the resulting dark matter (normal matter with no energy to keep them apart) is pulled together by their gravity (which is not lost in the ene
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I like this theory, as it ties together the theory of the heat death of the universe (energy depletion on a universal scale) with the possibility of a big crunch as the entire universe black hole collapses on itself. Theoretically, in such a massive way that the singularity could simply explode again, starting the whole process over.
Theorizing is fun. But I'm not technically knowledgeable enough about the subject to do anything more than toss out theory.
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Matter is energy.
For you to be right, Einstein has to be wrong (he's not - sorry)
No,They Don't Show That It Can Explain Dark Matter (Score:3)
Misleading summary.
Just read the paper abstract and what they have done is dispose of one problem in hypothesizing that primordial black holes could account for dark matter but not the several others that lead to rejection of this hypothesis.
From the abstract:
The hypothesis that these black holes have formed during the cosmic QCD epoch and make up all of the cosmic dark matter, has been rejected by many authors reasoning that, among other constraints, primordial black hole (PBH) dark matter would lead to orders of magnitude larger merger rates than observed.
So they remove the "could not exist" constraint, but not any of the "but could not account for other observational evidence if they did".
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Scientists Discover Proof Of The Unicorn's Existence
https://www.theodysseyonline.c... [theodysseyonline.com]
Ultimate proof
https://bolt3.com/15-magical-f... [bolt3.com]
TV Guide (Score:1)
Your black hole is popular now, I submit, because what you got out there is a bunch of depressed scientists. You’re not going to get any happy well-adjusted scientists inventing a big object, a black thing, that sucks you into a noodle shape object five million miles long and eats you up if you get to close to it.
~Simon Mendelssohn (Alan Arkin)
Simon(1980)
TV has taken refl
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You have not spent enough time in education-poor towns, I think. Low education increases the likelihood that people think they know everything. I think the effect you're seeing is real, but has always been a part of humanity (judging by quotes from historical documents). If anything, TV has (in my observation) reduced it by providing at least some awareness that the world is more complicated than the immediate surroundings.
X for unknown (Score:2)
To sum up for the lay person, galaxies should be wayyyy more swirly-licious than they are, given the age of the universe, but are, in fact, much closer to rotating discs. This means much of the mass of a galaxy is away from the core, out among the stars or further, countering the pull of the massive galaxtic core, so there's not really that much net gravitational pull coreward to make it like planets whipping around a star, or water around a drain.
When you add up all the stars outside the core, it's no way
If there are more than thought, then (Score:2)
things might disappear without wa`^ %~ [NO CARRIER]
there would be an uneven distribution (Score:2)
If there are that many primordial BHs out there, (Score:2)
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Extraordinary claims... (Score:2)
To resolve the dark matter issue, we must resolve the hierarchy problem, i.e. why is gravity so much weaker than the electrostatic force? There cannot be any consensus in physics because conventio
Quantized Inertia (Score:2)
building sandcastles of the mind.... (Score:1)
small holes can be a nuisance (Score:2)
"Their very blackness makes it hard to estimate how many black holes inhabit the cosmos and how big they are"
I was trying to read this story but distracted by a fly buzzing around the room. Buzzing? More like sizzling or crackling. Fortunately I had my bug zapper handy and after a few swats I got it. Bang! The bug zapper imploded into a tiny flash of light that instantly disappeared. Both the zapper and the bug dropped and seemed to fall right through the floor into the earth. Odd. But I got back to this st