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Black holes slamming into the moon could end the dark-matter debate:
Circa 14 billion years ago, when the universe's clock began to tick, space was still a tight, blazing hot, frenzied packet of cosmic stuff. Stars were yet to shine, planets hadn't been born, and jittery particles of every shape and size were zipping around at random. It was chaos.
But somewhere amid the lawlessness, in between spirals of stardust, a few minuscule, unstable and hyper-dense pockets of flaming matter might have collapsed. And if they did, scientists believe they would've dotted the early universe with clusters of black holes even smaller than atoms.
Don't let these petite spheres of doom fool you. A black hole half the size of a golf ball would have a mass equivalent to Earth's. Even microscopic black holes, with masses comparable to asteroids, would've unceasingly sucked in and destroyed everything along their path.
Slowly, as the universe progressed, swarms of them would have seen planetary systems rise and fall, and billions of years ago there's a fair chance they'd have even whizzed through our corner of the cosmos. Eventually, these mini black holes would've sailed away from each other. But if they did exist, experts think they'd still be roaming in and around the galaxies right this second.
They are, scientists believe, our newest lead on dark matter -- perhaps the greatest mystery of the universe. Dark matter quests that hope to unveil the strange, invisible particle or force that somehow binds the cosmos together often reach a wall. Solving the puzzle requires, well, actually... finding dark matter.
So to ensure this innovative hypothesis isn't a dead end, we'd need to locate unseen, miniature versions of black holes. But how? We have enough trouble finding supermassive, visible ones with high-tech equipment tailored to the search.
That's where the moon comes in. "There's this funny estimate that you can do," says Matt Caplan, an assistant professor of physics at Illinois State University and one of the theorists behind the research published in March. Caplan contends that if dark matter can indeed be explained by these tiny black holes, then at some point, they would have punctured the moon.
Yes, you read that correctly: The moon might've been bombarded by atomic-sized black holes. Taking it a step further, the wounds they inflicted should still be up there; if these mini-abysses are proven to exist, dark matter may no longer be an everlasting enigma.
[...] Though finding a submass black hole would be the holy grail for her work, she says finding implications of a potential dark matter black hole would suffice, too. That could be the consequences of dark cooling processes.
"What's interesting about this," she says, "is if you continue not to find something, it's a complementary way to constrain the nature of dark matter."
Essentially, it's a process of elimination.
But even if we can never find it, and it's not atomic-sized black holes slamming into the moon, dark matter's purpose will live on until the end of the universe. Until then, the cosmos will continue to tick along its linear timeline.
(Score: 3, Interesting) by Anonymous Coward on Friday November 19 2021, @09:45AM (11 children)
Hawking radiation. And other things too.
Dark matter didn't only exist in the early universe, it still exists today. The amount of dark matter doesn't seem to be increasing or decreasing very much. Black holes have an annoying property of either accumulating or emitting mass. If the temperature of their Hawking radiation is greater than the temperature of the CMB, they emit it, otherwise they accumulate it. (Or rather, they always both emit and accumulate, but the temperature determines which one dominates).
Today, any black hole with mass about equal to the Moon or less will lose mass to Hawking radiation. Black holes of roughly asteroid mass or smaller would have completely evaporated by now. Black holes in between those sizes would be shining brightly because of their Hawking radiation. Not as bright as a star, but bright enough to see, if they were whizzing through the Solar System. And if they were much more massive than that, we could detect them by their gravitational effects. And, of course, there's no explanation on offer for what could have formed all these macroscopic but less-than-stellar-mass black holes.
Basically, MACHOs just don't work, which is why everyone is looking at WIMPs (or trying to change the law of gravity).
(Score: 1, Interesting) by Anonymous Coward on Friday November 19 2021, @11:23AM
Black holes in the 30 - 70 solar mass range are still a viable dark matter candidate. Interestingly the LIGO and VIRGO gravity wave detectors found many more merger events in that range than they were expected to.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @11:37AM (1 child)
The mass remains the same, whether it's inside a black hole or not.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @01:52PM
But it wouldn't be dark matter once it leaks out of the black hole. It's impossible for small black holes (other than Planck particles) to be dark matter because the amount of dark matter would change over time as the black holes evaporated.
(Score: 1) by shrewdsheep on Friday November 19 2021, @01:05PM (7 children)
This assumes that the black hole is far away from other masses. My problem with TFA is to understand how black holes can be within the moon without sucking it in completely. Maybe they were hitting the Moon at high velocity but how could they tunnel out again? I would expected a non-penetrating collision.
(Score: 2, Interesting) by khallow on Friday November 19 2021, @01:33PM (2 children)
By merely passing through the Moon. The amount of mass they would encounter with their extremely small cross section is way less than the mass of the black hole.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @03:24PM (1 child)
Like a bullet through paper, only like really really thin paper.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @06:18PM
yeah.
but how about, say ...mmhhh... we define a pencile of "1 (unity) blackhole mass". it is a pencil, because it is pencil shaped and not a working blackhole since it's mass is " diluted" over a too great a space/area.
so now a real working blackhole, with1 (unity) blackhole mass, hits it head on... say both objects have velocity x but opposite direction.
if the functioning blackhole gobbles up the pencil, we have feed the blackhole to size 2 and it is now at rest (relative to x speed) before.
point is, a micro blackhole "digging" a tunnel thru any object would influence that tunnel-thru objects world-line in space/time?
(Score: 1, Interesting) by Anonymous Coward on Friday November 19 2021, @01:41PM (3 children)
Black holes don't really experience friction. Assuming one is moving at interstellar speeds, it would bore a perfectly smooth and nearly perfectly straight hole through whatever it hits. The tunnel would then collapse, causing a quake (not sure off hand how severe of a quake).
The black hole would also emit Hawking radiation as it traveled, and some of the mass it passed through would be heated through interaction similar to an accretion disk (although it would be more like an accretion shock wave). This would release a lot of energy, on the scale of an asteroid impact, but most of it would be deposited deep within the moon/planet.
I agree that it doesn't seem likely that a crater would be formed.
(Score: 2) by fraxinus-tree on Friday November 19 2021, @04:17PM (2 children)
A black hole that has acceptable lifespan (IF the Hawking radiation is a thing) will be big enough to have an impressive tidal effect on the Moon. Like, e.g. completely blowing it apart. The debris and the acretion disk radiation will rather make the Earth unhabitable.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @04:52PM
It might be counterintuitive, but an Earth-mass black hole would pass right through the Earth, or the Moon, without having any major effects on their structure.
(Score: 0) by Anonymous Coward on Monday November 22 2021, @08:24PM
I was going to say it if no one else did -- the matter might be resolved once and for all due to a dearth of Earth inhabitants to keep asking about it.
(Score: 2) by bradley13 on Friday November 19 2021, @11:15AM (5 children)
Hawking that tiny black holes explode. Black holes aren't black - they emit radiation as they eat half of virtual particle pairs. The smaller the black hole, the more (proportional to its size) Hawking radiation it emits. So saying "if they did exist, experts think they'd still be roaming in and around the galaxies right this second" is incorrect. Unless these "experts" have disproven what Hawking proved, tiny black holes created billions of years ago would have long since evaporated.
Dark matter most likely doesn't exist. Dark matter is a placeholder for something that we don't yet understand. On large scales, spacetime bends in ways that don't match our current equations. You can sort of, kind of match that bending with various possibilities. Actual, physical particles that only interact gravitationally and are otherwise invisible? Maybe, but frankly, one of less believable theories out there...
Everyone is somebody else's weirdo.
(Score: 3, Interesting) by pe1rxq on Friday November 19 2021, @12:43PM (2 children)
Just rewriting physics on large scales is also in trouble: There are galaxies that seem to not need (and thus presumably do not have) dark matter. (e.g. DF2)
If dark matter is a particle that is no problem at all, those galaxies would just have less of them. If you want to bend space differently you need a new explanation for those places to make sense.
(Score: 2) by PiMuNu on Friday November 19 2021, @01:55PM
DF2 is quite interesting. I just had a look. Thanks for the tip.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @03:41PM
This is one of the best arguments for Dark Matter, but it also runs into another problem, IMO.
See, the Ptolemaic Universe (moon, sun and planets orbit the earth in circular orbits around circular orbits at a non-constant velocity) was able to perfectly match the observations of the sky (only truly falling out of favor once we found moons around Jupiter), the problem it had was that it also could account for ANY conceivable observation, which means that the model wasn't predictive, it didn't say what was or wasn't possible.
Dark matter likewise has too few constraints to be predictive, IMO. You can just sprinkle enough into whatever galaxy you observe to account for the rotational disparity you need to account for. The only thing it can not do is account for galaxies that rotate too slowly, so I suppose the absence of any observations of galaxies that require a negative amount of dark matter does lend it some credence.
Don't get me wrong, I think Dark Matter is the best current hypothesis, and I want to see it proven either right or wrong, but the idea doesn't give me the warm fuzzies of even QED where even though you need imaginary numbers and probability waves to make it make sense, its predictive power seems to preclude it be terribly wrong. Yes, it predicts not only that any thing CAN happen, but also that everything DID happen (at least partially), but at the end of the day, the probabilities cancel out and the observations match the predictions to a crazy degree. I don't mind my science being weird when it has to be, but I like when it predicts what will happen rather than just explains what happened after the fact.
(Score: 4, Interesting) by HiThere on Friday November 19 2021, @02:26PM (1 child)
My favorite answer (just mine, no equations to back this up) is that there's a point at which black holes get too small to emit radiation. Their capture cross-section gets so small that they can no longer capture half of a virtual particle. Then they stop evaporating. But they're also too small to capture anything else unless the matter is packed, say, as densely as neutronium. So their sole predictable interaction is a very light gravitational force. They may also be charged, but the orientation of the charge (positive or negative) wouldn't be predictable.
So there they are, zipping along, contributing a bit to the curvature of everything and adding a bit of em-noise. Frictionless except for that em-interaction which might alter their courses slightly. Just how to detect those ... well, that's a difficult problem. I don't think they'd leave tunnels on the moon.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 1, Interesting) by Anonymous Coward on Friday November 19 2021, @04:37PM
Those are Planck particles. It's a real theory. It's still speculative because quantum gravity is necessary to understand the behavior of Hawking radiation on such small scales.
Even if these don't turn out to be a significant factor in dark matter, they still might be physically possible. Or maybe small black holes just evaporate to nothing.
(Score: 2) by Gaaark on Friday November 19 2021, @02:00PM (1 child)
"What's interesting about this," she says, "is if you continue not to find something, it's a complementary way to constrain the nature of unicorns."
I've been looking for unicorns EVERYWHERE and cannot find them ANYWHERE. But imma keep looking because it's a complementary way to constrain the nature of unicorns.....
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 1, Touché) by Anonymous Coward on Friday November 19 2021, @02:14PM
We do have unicorns, they are just short and chubby and grey.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @02:43PM (3 children)
Is a black hole really a infinitely large atom nucleolus, because of packing of the atoms so close that nucleoli "merge"?
Hence, all black holes (dark matter?) are really just new elements on periodic table. They used use fusion by the power of gravity, to create newer even larger atoms.
(Score: 3, Informative) by DrkShadow on Friday November 19 2021, @03:33PM (2 children)
That would be closer to a neutron star, I feel like.
All the subatomic particles -- quarks, gluons, electrons, etc -- merge together and form one giant particle. A proton is a collection of pieces, and so it's not represented distinctly, and there aren't massive numbers of separate neutrons. Just everything all merged together and there's "one". All the electrons impacted all the protons and you're left with soup.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @04:58PM (1 child)
Yes, although neutron stars are considered stars, not particles, because they're held together by gravity and not the strong force, and they have a complex structure. They probably have layers, with an iron crust, a dense plasma "mantle" with increasing numbers of neutrons as you go deeper, and then a core of pure neutrons or possibly exotic matter (quark-gluon plasma, strange matter, etc). Nobody really knows for sure what goes on in the core.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @07:17PM
Should we ask mister owl?
He knows the number of licks to get to center of tootsie pop.... 3.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @08:29PM
We'd all be kaput - won't be debating no nothing.
(Score: 0) by Anonymous Coward on Friday November 19 2021, @10:32PM (4 children)
I read it 20 or 30 years ago. It was about tiny black holes created in a physics lab or accelerator and they'd oscillate through the Earth poking holes as they went through. I can't recall the book author(s) or title for the life of me.
(Score: 1) by CCTalbert on Saturday November 20 2021, @01:39AM (2 children)
What I remember is a fusion experiment where they're basically doing the laser-ignition of a pellet scheme, and are creating microscopic black holes, that are trapped in the earths gravitational field, oscillating back and forth causing mayhem. Somehow related is an experiment of some sort that they use to send a message back into the past telling them not to do that. Don't recall how they resolved the paradoxes involved. I think I read this in HS which would have been early '80s. Many years.....
I thought it was something like "echo round the bones" or something like that, I've searched and can't find it, did find something called "Echo Round His Bones" that is a different story. It may be that the title includes neither "echo" or "bone". :)
(Score: 0) by Anonymous Coward on Saturday November 20 2021, @03:28AM
Yeah, that sounds like it. After all these years all I remember from that story is the black holes oscillating in the gravitation field because I thought the was pretty cool, but damned if I can remember the story it came from.
(Score: 1, Informative) by Anonymous Coward on Saturday November 20 2021, @03:42AM
Aha! I found the one I was thinking about: The Krone Experiment by J. Craig Wheeler. Published in 1986, which would be the neighborhood of when I would have read it. Apparently made into a low budget movie too. And there was a sequel that I never read.
(Score: 0) by Anonymous Coward on Saturday November 20 2021, @03:30AM
Dragon Evg is not the book but it too has mini black holes that population living on a vnetron star used to have gravity off of home star surface. They took them from our sun abd stop the solar flare cycle.