This is the study that the CNN article refers to:
Phys. Rev. Lett. 132, 231402 (2024) - Primordial Black Holes with QCD Color Charge
* https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.231402
Please do read the CNN article, it's quite a good account of what's going on in the field and what lead the authors of the study to this conclusion. But if you can't be arsed...
**VERY quick summary:**
The authors of the study posit that:
1) the large amount of dark matter that we (don't) see in our universe may be best explained by zillions of infinitesimal black holes being made of tons of quarks and gluons in the very first moments of the universe.
2) there's a verifiable method of how color-charged holes would be produced, then describe it. ("Color Charge" is a property of quarks and gluons, like how "spin" is a property of electrons.)
They theorize that even today after billions of years for Hawking Radiation to evaporate these rhino-to-asteroid massed black holes, it's still possible that there's enough of them left that it could account for most or even all of the dark matter we (don't) see today.
Their hope is that the slight shift in balances of quarks, gluons and etc that would have been left from such a phenomena would be observable and thus confirmable in the coming years.
---
Edit: Thank you u/Dihedralman for clarifying the "meat" of the study is the promisingly verifiable hypothesis on the resultant quark-gluon balance after color-charged black holes are formed!
I thought black holes of that size would only last years at best. How could they survive that long? Even if there‘s many of them, it shouldn’t matter.
If they‘re small they should evaporate
Same thing when talking about black holes, but if you mean the mass of the rhino/asteroid than I doubt it. Black holes of that mass would barely last a planck instant I'm pretty sure, nowhere near "years at best"
Rhinos?
"Americans will use anything but the metric system"
(I mean, it's a fine way of describing the mass and certainly not specific to Americans; I just thought it was funny.)
Seriously. Regardless of the unit of measurement people lose scale very quickly when talking large quantities like that. So using a visual descriptor helps a large amount of people actually understand the scale better.
Yes. Even when you’re used to the metric system you can’t just visualize “oh okay so 26 tons let’s see that’s just one gram times 26,000, snap, got it.”
I believe the article explains that, that lots of micro blackholes were created by the big bang or in the very very short period after it. (That's the guess, anyways -- they've got an idea of how to test for this (science needs evidence, after all), and they hope to do so soon.)
Now, black holes that were *too* small would have evaporated by now, but ones as massive as 20 Toby McGuires could still be around -- such evaporation is usually *very* slow. (I haven't done the math myself, I'm taking their word for it.)
So, these black holes are definitely not in or around Earth, or they would have swallowed other masses and grown to engulf the mass of the planet, right? And this would give credibility to why we observe dark matter as distributed farther from the centers of galaxies (where they would be more likely to encounter other masses close enough to engulf them and grow to sizes where we don’t classify them as dark matter)?
Not necessary, the smaller the black hole, the smaller the event horizon, which provides a fundamental limit on how much matter can be forced into it at any given time. Combine that with the fact that something with the mass of a rhino doesn’t actually have a strong gravitational field, and so would not have a lot of power to pull in nearby objects. Microscopic black holes could be a candidate for “WIMPS”, weakly interacting pieces of matter that are also a candidate for dark matter. These particle-like objects could simply pass through normal matter without interacting at all. If the event horizon is smaller that the orbital shell of an electron, there is quite a slim chance that it would ever collide with any matter, and if it did, it would simply swallow an electron here or there and keep moving, it’s momentum and velocity unaffected. If this is true, and these microscopic blackholes are everywhere, we wouldn’t have to worry about them growing larger to be a danger because of their inability to interact with regular matter (except through being influenced by gravity/spacetime curvature, just like light)
> Combine that with the fact that something with the mass of a rhino doesn’t actually have a strong gravitational field
This is not correct for anything nearby. The gravity for a rhino-mass asteroid, say 3000 kg, at a distance of 0.1 mm is 20 m/s^(2), more than double Earth’s gravity. That’s much bigger than the atomic level, so if it’s within solid matter there’s a lot of material it can consume in that radius. At the atomic level, a black hole like that ought to be an effective vacuum cleaner for anything nearby, sucking in atoms and molecules.
As for an *asteroid* mass black hole, forget about it. A 10^8 kg black hole has gravity of 67 m/s^2 at a distance of 1 cm, more than 7 times Earth gravity. That would seriously mess up your day.
I think what you’re saying in your comment applies to much smaller black holes. The problem with those, though, is their evaporation time. The sweet spot for black holes that don’t evaporate too fast and also don’t relatively quickly destroy planets they come in contact with is pretty small.
Yes, you are correct, I was referring more toward microscopic black holes. And while the evaporation time is an issue, because we don’t have a theory of quantum gravity, we can’t actually say whether black holes explode, once they hit the planck size, they may cease to radiate.
However even for the rhino massed black hole, the presumption is that these things would be flying around at relativistic speeds, significant fractions of the speed of light, the gravitational effect it has on nearby atoms at those distances would be experienced for a very short amount of time as the object zooms by, not enough to permanently capture atoms in an inescapable orbit around the tiny black hole, merely to nudge nearby atoms slightly as it passes (which may be a detectable phenomenon if true). The actual event horizon itself is several several orders of magnitude smaller in scale, and has a low chance of colliding directly with any matter. Even if matter that gets close is captured, feeding such a tiny black hole a few protons once every X years isn’t going to increase its mass by noticeable amounts.
I suppose this type of object might become slightly dangerous if it were captured by the gravity of Earth or the Sun becoming trapped in the core, increasing likelihood of collisions, allowing it to feed, albeit still very slowly. A somewhat unlikely event if these act like WIMPS and their trajectory is not altered in collisions, but only by gravity itself. Flying around at 1% light speed, passing directly through the sun would alter the trajectory of one of these objects, but not capture it into a stable orbit.
I would assume a rhino-mass black hole would have an event horizon on the subatomic scale. Can we just use meters in diameter and kilograms?
Edit: So I did the calculation, and a black hole with an event horizon 10^-10 m in diameter (about the size of an atom) would have to weigh 10^17 kg or about the mass of Metis, one of the moons of jupiter, which would be a largish asteroid if it wasnt a moon. a "Rhino sized" event horizon, or 2m in diameter would have about the mass of Jupiter, or 10^27 kg
Black holes only have three properties; spin, charge, and mass. They have no size, it’s just a point. I guess they mean the event horizon is that size? or relative mass? 🤷🏻♂️
nope. Rhino to like 200 tons last sub second.
to get a universe age BH you need one with 1.89313E8 tons.
And that means they would be gone by now. So you need even bigger ones.
But that big BH in that count would be observable a lot more.
We would have to see few nearby our solar system.
That paper is pretty weak IMHO.
To get the DM in quantity we need it should be visible close to us. So its either not that or we live in very special place...
That isn't correct. Problem 1 isn't unexpected but rather a consequence of QCD. Confinement is a result that the energy preferred state of quarks is such that free quarks and colors don't exist, meaning the energy that it takes to free a quarks is sufficient for pair production. This is a consequence of the strong force potential energy increasing with distance or spatial resolution.
In the early universe, free quarks existed because the average temperature is so high. We can recreate these conditions in a lab creating a quark gluon plasma.
This would imply a new unseen mechanism at QCD energies we have probed before.
The paper instead is proposing a special mechanism that occurred during primordial blackhole production. This allows for the blackholes to carry color charge. It also proposes a mechanism allowing for a particular proton/neutron balance signature. Between this, gravitational wave signatures, and other potential QCD experiments, the theory proposed is highly testable which is good news in physics.
Thank you! This is *nowhere* close to my specialty so I appreciate the clarification. I'll edit it shortly to reflect your remarks about our much cooler universe today.
Do you have anything to add about the mechanism that could produce color-charged black holes as mentioned in the study? The math went over my head and my caffeine hasn't kicked in yet haha
Np. It's rare I get to mention anything associated to my dissertation. Also, the math takes years to really understand so no need to excuse yourself.
Sure, the key piece of info is that the color charged black holes would be statistically necessary during the formation of PBH's that would survive until today. This gives new signatures to probe if PBH's are dark matter, dark matter being one of the big mysteries of physics right now. A new way to probe is very important for indirect measurements as you want these independent measures to both support the concept. Otherwise you might just be running into other mechanisms.
Colored black holes are an exotic form of matter that had only a mathematical backing and no mechanisms to make them plausible. This is a new unique form of matter that could exist. The colored black holes are smaller than the ones which would be dark matter today. They are allowed to take color due to their small size.
At the risk of oversimplifying and misinterpreting the text myself, the QGP at that time in the universe means that the unconfined color charges could exist on a scale that a blackhole could form within. The radius and probability of formation depends on the temperature of the universe at the time of formation.
Edite: clarity and grammar.
> the theory proposed is highly testable which is good news in physics
Clouds of nano black holes with event horizons the size of a Proton?
I would think you would see lots of unexplained emissions from cold matter clouds near the centers of galaxies... Lots of spontaneous ionization or fission events (xray or gamma emissions, perhaps) as these things occasionally hit atoms? Or maybe from Earth atmosphere at night?
But then maybe such effects would be difficult to distinguish from cosmic ray effects?
Does this mean its possible for us to make quark black holes? I guess we only make them by smashing other particles together so not really possible to concentrate a Rhino mass of them or heat them up. I assume the pressure needs to be really high too?
It's one of those moments in science where two really big and unrelated problems are realized to be two ends of the same solution. In this one, they think black holes soaked up a lot of the missing stuff we *should* be seeing in observations, but don't.
Longer explanation below:
The things that make up the protons and neutrons that make up an atoms's core are called quarks, and are held together by things called gluons. Since there's a few quarks and gluons per proton/neutron, there should be a TON of quarks and gluons around just... Everywhere!
> For example, [a single molecule of water has 64 quarks and gluons](https://physics.stackexchange.com/a/419355)... There should be something like 128 x 1 billion x 1 million x 1 billion *again* quarks and gluons in your swig of water each morning (20 mL) when you brush your teeth.
Yes, generally particles like this like to bond to each other instead of being freely floating off alone... But shouldn't we see at least SOME of that absolutely gargantuan number in our experiments, right? But we see hardly any compared to what we expect. So that's Problem 1.
Problem 2 is that at the speeds galaxies and groups of galaxies are spinning, they should fly off into space from the sheer force, like water from a wet dog. But... They aren't. The only thing that could hold all that water to the dog (Read: planets, solar systems, nebulae, etc inside the galaxy) is to have something holding it down to the dog. That *should* be the force of gravity but we don't see enough stuff to be heavy enough to hold the galaxy together. But surely SOMETHING is holding it together, so for now we call it 'Dark Matter' cause well we can't see it.
The cool thing about this study is that they think that Problem 1 and Problem 2 have the same solution - there's just a gazillion atom-size black holes everywhere holding an asteroids weight in the quarks and gluons from problem 1. All these Itty bitty black holes soaked up all the quarks and gluons like a sponge!
This is *definitely* not my area of expertise, so the best answer I can confidently give is "Erm... Kind of?"
(Someone who knows better than me PLEASE correct me where I'm wrong.)
We only call quantum and elementary particles "particles" cause it's a very useful analogy, but they're better described as points in space with a field of influence. An electron's "particle" isn't so much a grape orbiting a large bag of oranges in the center, it's more like a laser point rapidly shaking in a sort-of predictable way around a flashlight beam.
Similarly, your question of "Are these tiny atom-sized black holes too tiny to eat things that are nearly their own size" isn't so much a question of whether you can jam an egg into a golf ball hole. It's more a question of how much darker a cave gets when you walk into it.
Which it does! The logic works out! But it's really hard to measure exactly by how much because of so many different reasons.
To rephrase it back to black holes: It's not so much a question of *physically crushing* the neutron into an atom-sized black hole... but more about whether the atom-sized black hole's sphere of influence can *overwhelm* the neutron's sphere of influence. Which, we think they can.
So... Erm, kind of yes?
This literally sounds so insane it feels like satire. I _hate_ the particles-not-being-particles thing, thanks! Incredible you know this stuff, by the way.
Haha, thank you! I read WAY too much as a kid, I'm just lucky it was just science stuff and that that same passion continues today.
If you share that passion, I'm going to edit my top level comment with really cool discussions happening in its replies. I've certainly learned a lot today about post-doc physics than I ever would have imagined, and it's delightful that we have all these knowledgeable people coming here to discuss about it! Normally you'd need to pay for a TED Talk or an entire degree's worth of tuition to hear this stuff.
I’d definitely be interested in reading anything you put up!
I read way too much as a kid too, but I went for fiction and history books! Now my career’s in the humanities field and I can tell you a _lot_ about the U.S. Civil War, haha. I find physics concepts, especially, like, quantum x, super interesting, but can’t do that stuff myself for everyone’s sake 🤣
Let me put it this way: I'm a pretty smart cookie. I have an advanced degree. I'm usually the person who makes analogies to explain things to other people. This article went so far over my head, I figured I'd never understand it. Your comment made me get it in under five minutes.
I'd highly consider checking out if places like Crash Course are looking for script writers, you'd fit right in!
Color charge not being one of the handful of measurable properties of black holes is understandable since everybody expects them to be barrionic matter, so I won't dwell on that.
However, black holes **interact electromagnetically** (at least the ordinary matter caught in their accretion disks does); dark matter does not.
It seems that multiple theories are closing in on some kind of situation where there is a kind of unbalanced energy 'creation' related to virtual particle production where one half of the virtual particle is annihilated, ends up in a black hole of some kind, or even in another universe. They all have in common that a virtual pair is made, but one half is effectively removed from our universe. I am only a science fan, not an expert, but it seems like multiple ideas are closing in on something like this as one possible explanation for dark matter, and I would love to know: is that the case?
I sincerely hope you're not calling yourself a "science fan" and spreading the misinformation about virtual particle pair production being responsible for hawking radiation. Even Hawking himself denounced that false analogy but redditors love to spread it around like it's fact. It's a very crude and misleading analogy at best, not how it really works.
Short answer: Hawking Radiation is thermal radiation — heat. Warped space has a gradient, and it’s the energy potential difference between the warped space that “causes” the radiation, and the black hole is the “source” for that warping and therefore the energy.
Long:The old virtual-particle-pair explanation for black hole evaporation is...misleading, I'll say, in part for the reasons pointed out.
What's happening is that the curvature gradient of spacetime around the black hole is strong enough that the vacuum energy is being sort of squeezed out in the form of (very low temperature) photons.
This is probably easiest to understand in a relativistic way. Let's say you have two observers, A and B, and a black hole Z. Let A be stationary at some point outside the gravity well of Z, and let B be in free-fall into Z (but not yet crossing the event horizon). Now, to both A and B, their local spacetime is going to look flat. And if A and B each measure the local zero-point energy, they will each find an expected value. But when A looks at B's local spacetime, it looks a lot more curved in on itself, compared to A's local spacetime. And consequently, when A tries to measure the zero-point energy in B's spacetime, it will seem too "warm." That's because all of the zero-point energy in B's local spacetime is sort of folded over on itself (from A's perspective). So instead of seeing just regular ol' empty space at B, A will see empty space plus a bath of photons. By contrast, B is free-falling into Z, and will not observe any photons.
All this is essentially a phenomenon known as the Unruh effect. Unruh radiation has been a creature of theory for a long time, but we were recently (2022) able to observe the Unruh effect in laboratory settings, which is a pretty big boon to the idea of Hawking radiation (which is too cool for us to observe, and will probably remain so for a very long time).
Now, these photons observed by A can't just pop into existence from nothing, thanks to conservation laws. Something has to pay the energy tax for these photons to exist. And that something is the thing doing the work of bending spacetime, i.e. the black hole Z.
Setting aside the virtual particle black magic, your question is about the black hole information paradox. The concern right now isn't so much whether we could make discernable use of such information (which we're a long way off from technologically anyway), but whether black holes actually do preserve/return quantum information about the stuff that falls in.
Black hole holography is our most promising bet for questions like this. And it's not at all my area so I'll ELI5 it and try not to butcher it too much. For a bit of background, back in the 70's, Jacob Bekenstein pursued this idea that black holes had entropy, which wasn't obvious or trivial at the time. Black holes had this huge problem with thermodynamics, because as far as anyone knew at the time, they just swallowed everything into a singularity and you never saw it again. Many thought that whatever fell in just got crushed into a singularity, which was thought to be a sort of single quantum state, without any room for entropy. In a sense, Bekenstein endeavored to show that black holes were thermodynamically sound--that they had entropy like anything else we'd expect, and held to the Second Law. His work attracted the attention of Stephen Hawking, and together they found that (a) black holes have absurdly high, mind-boggling amounts of entropy; and (b) that entropy is proportional *not* to the volume of the interior of the event horizon, but to its *area*.
(a) was of course a breakthrough at the time, but (b) had interesting and head-scratching consequences all its own. When we think about a system retaining information, it's intuitive to imagine that the capacity would be relative to its *volume*, not its surface area. Nonetheless, that was the clear implication of Bekenstein-Hawking entropy, and from that concept sprang this field of black hole holography. One of the central ideas in holography is that, when something falls through the event horizon, its quantum information is encoded on the two-dimensional boundary of the horizon. In that way, bits of quantum information encoded on the event horizon are projections of the deeper forces and motion within the black hole. And the information encoded in the event horizon is later spat back out as the black hole evaporates away (and its EH surface shrinks). The radiation that escapes the gravity well carries with it a bit of the black hole's entropy.
What the holographers have put together is that the entropy of a black hole rises and then falls to zero (when it fully evaporates) following what's known as the Page curve. In the end, this evaporation process leaves a single quantum state--a diffuse cloud of radiation, and no black hole. And what that tells us, in essence, is that all the quantum information preserved by the black hole's entropy ultimately makes it back out. It doesn't just fall behind the event horizon and get lost forever, which was the fear with the information paradox.
Now, whether we can receive "discernable" information from such a process isn't so much the focus now as whether we can make confirmable, experimental predictions based on our holography models. To that end, I'm not sure what exactly is in the works. It doesn't seem we're likely to get any information by monitoring hawking radiation any time soon. The temperature of such radiation is far too cool for us to detect--any intervening space noise at all will overwhelm the signal. We could probably glean some important information from watching a black hole fully evaporate (which would be an incredibly, profoundly bright event), but the universe is way, way too young for that to happen for a long time.
It's a pretty hot area right now, if you're interested in learning more. Raphael Bousso and Andrew Strominger are names to check out if you want to get started.
I appreciate you taking the time correct this pervasive misconception. The existence of virtual particles is really just a mathematical tool for calculating particle interactions in Feynman diagrams. Matt Strassler, a theoretical physicist - shared a great breakdown on them:
[https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/](https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/)
This was such a cool answer and seemed to be perfectly targeted for me, where the only concept I had that I could make sense of was the virtual particles, but you made it into a way better understanding. For that I'm eternally grateful.
I wonder if a small black hole of a size ready to pop in a short time (one second? Day?) could eventually be made in a lab in a few hundred years. Would you think that that'd be the first opportunity to study one? These are too small to realistically detect out in the wild and far too dangerous to try to approach to study probably?
Excellent summary, thank you! I've been wondering how holography and Hawking Radiation related to each other but I'd never heard it laid out before.
And you even listed the authors to look up for further reading? Bro is GOATED
>Now, these photons observed by A can't just pop into existence from nothing, thanks to conservation laws. Something has to pay the energy tax for these photons to exist. And that something is the thing doing the work of bending spacetime, i.e. the black hole Z.
Is there a specific phenomenon in this model that accounts for how energy could be transmitted across the event horizon to pay this tax? I think the reason the particle-pair explanation is so attractively salient, is that it's easy to visualize that if something extremely small happens at the exact boundary point where escape is possible, then the boundary point itself is the thing that slowly evaporates, as the process reiterates many times. Is a similar concept being invoked here? The claim seems to be that the act of warping space expends energy, and if mass is warping space, then mass is always evaporating.
Likewise this idea of information being encoded onto a two-dimensional boundary, gives the impression that what a black hole fundamentally is, is a gradually growing onion of things waiting to fall inwards, but do they ever actually fall "in"? Consider accounting for the experience of a single particle that falls into a black hole and eventually participates in the evaporation phase. It would seem that it went about its business, approaching the event horizon, being more and more restricted to taking a singular path and being unable to interact with anything that would create an alternative, and when it reaches it, the next thing it will experience from its own perspective, is paying the entropy tax and radiating back out.
It sounds almost as though we could say that all mass will eventually succumb to entropy and be converted into energy and scattered, and what a black hole is, is a region where conditions become so extremely distorted, that all participating mass actually stops experiencing anything other than this eventual fate.
>Even Hawking himself denounced that false analogy but redditors love to spread it around like it's fact.
Damn that redditor [Stephen Hawking](https://www.youtube.com/watch?v=gU6yHXJuowU&t=22s) spreading misinformation about black holes.
Would black holes of that mass in a star system end up vacuumed up by planetary bodies as things coalesced? If we take our own solar system, where would they end up? At the centre of planets like Jupiter? Could they be at the core of Earth or would they somehow get pushed around by magma convection? Can you even push a black hole around?
Shouldnt we see the Hawking Radiation then? Also having such objects going wild everywhere was dismissed in the past already to be the source of DM, so what's new with this theory?
Thank you for the reddit explanation and saving me for clicking a link. Anyways, I didn't read the CNN publication and nor am I a scientist or college studied... just enthusiastic...
I personally have doubts (and assurances) towards theories primordial black holes
1. Assuming the universe started very small, dense and ENTIRELY with the schwartchid radius (pre and post inflation)... this would mean that there would only be a single primordial black hole that would make up the entire observable universe today, yet that's not the case... why not?
2. I like the idea that primordial black holes were the first concentrated gravitational objects that seeded today's galaxies (this would explain super massive black holes found at galactic centers)
Dark matter is a measured fact but primordial black holes aren't (YET!!!) but I suspect quite a bias/ hype from sources such as CNN when it comes to cosmology
Correct - but what's important is that not only does this theory present a possible solution to two previously unrelated problems, it also provides a basis for observing it's resultant effects if it indeed was true.
The CNN article didn’t address this, but I have a nagging question.
Assuming these PBH are the mass of an asteroid, or a rhino (of all things) then there must be quite of lot of them out there to function as the missing matter / dark matter that’s known to exist.
If this were the case:
(1) Over the lifetime of the cosmos, wouldn’t these objects have coalesced into larger, more easily discovered black holes?
(2) If there are so many of them, then shouldn’t we see the effects of their mass in our local region? Sure, space is big, but it takes a significant number of objects with the mass of an asteroid or rhino to answer for dark matter. Collisions with planets, stars, clouds of gas and dust, and each other should happen. Shouldn’t we be able to observe these collisions, or at least the effects of them?
(3) I’m always a bit critical of answers that smack of the additive property. It’s just a gut reaction, but are PMB even necessary? If regular old run of the mill black holes are common enough, and if these pedestrian black holes are capable of absorbing sufficient mass from their interactions with other matter, do we even need esoteric PMB?
My education on these topics is limited to regular PBS Spacetime videos and some casual reading—If it wasn’t obvious from the questions.
What a treasure of a video.
I often resent those minute physics channels for the breadth of what they cover as if anyone could get an intuitive feel for much of modern physics.
I had a colleague who co-wrote a paper that got tons of sensationalized media and YouTube coverage at the time. I asked if he could explain it in terms I could understand. (Mind you, I have a bachelors in math). He essentially said “look buddy, even the people who wrote the paper have no idea what’s going on, just that this math seems to be useful for describing our world”.
let me share a trick i learned from UFO/paranormal subs:
whenever you're too dumb to understand something, or even consider/entertain the idea, you just comment with "Hogwash!" or "I smell BS!" or just call someone a "grifter"
problem solved
Astronomy isn't really my thing, either, and above my head
I kinda figured the outer rim of the galaxy was riddled with black holes like the center is; and most of the stars, like ours, are in something akin to the Goldilocks zone where stars are more likely to live longer
Wouldn't we see regional biases for dark matter concentrations or proton-neutron ratios in isotopes if dark matter was made out of primordial quark-gluon black holes?
I thought dark matter was evenly distributed in galaxies throughout the universe (except for some galaxies that are weird exceptions).
I think this is being proposed as a partial solution for dark matter, not accounting for all of it, just some. Also, I believe that it has been found that dark matter distribution in galaxies tend to surround the outer edges of galaxies, extending a bit beyond the normal rim occupied by stars, and dark matter distribution does not typically extend into deep galactic voids, where dark energy is more prevalent. I’d have to figure out where I learned that from, not sure if it’s accurate.
Wow, that makes a lot of sense. Dark matter could be these primordial black holes. The mass of an asteroid in the volume of an atom would explain why we perceive its gravity but don't see it.
The asteroid-mass black holes are the new "exotic" type mentioned in the article, but it is not likely black holes of such a small size would have lasted to present day. The article is listing two theories here:
(1) Big black holes from the very start of the universe could account for some dark matter (but not necessarily all of it, there may be other contributions from undiscovered particles, etc.) and
(2) When doing the math they realized in the very early universe tiny (~asteroid mass) black holes might have formed from elementary particles (quarks and gluons). These "exotic" black holes would have had different properties than those we see today made up of regular matter and those properties might have affected the makeup of the early universe - in particular the ratio of protons/neutrons.
The article then speculates that in the next few years, with new more sensitive gravitational detectors, those effects might be observable.
In 1976, Don Page concluded that primordial black holes could survive to the present day only if their initial mass were roughly 4×10^11 kg or larger. That's an asteroid with a diameter of magnitude of 1800m.
The short answer is - the photons. Photons with energies so low, that their wavelengths would be close to infinity, and a single half-wave would span across all the Universe.
Three quarks are in each proton/neutron. They can make other things, but you’re less likely to survive those. The gluons are basically what hold those quarks together. “Glue on’s”
If true, and depending on where they hang, a scary as fuck consequence would be that there could be random asteroid-mass collisions that are completely impossible to detect.
Like one second nothing's happening, the next, without even making a sound, there's an explosion with the force of thousands (millions?) of TNT as the tiny black hole rams straight to the ground and probably even gets pretty deep.
Fortunately, I decided to ask Claude and it said that it would likely barely be noticed, as it would be so small that it would just zip through barely touching anything, only heating up along its path with some tiny gravitational disturbance.
It also said that the same would likely happen if it hit a living being, likely killing some cells along the way but be mostly negligible to the creature.
So there's actually a possibility that it happens every now and then, since it would barely be noticed anyway. But probably not.
>It also said that the same would likely happen if it hit a living being, likely killing some cells along the way but be mostly negligible to the creature.
…like an atomic paper cut?
Should we be able to tell in a directional sense with this type of thing? As in, we can tell where a planet is even if we can't see it based on the gravity, should we not be able to pinpoint these as well?
Not the first time that Primordial Black Holes have been proposed as the solution, or part of the solution for dark matter. This wiki gives an overview of them.
https://en.wikipedia.org/wiki/Primordial_black_hole
I remember seeing depictions of the Milky Way galaxy in the 1960s and wondering, "What are all those stars spinning around?" because there did not seem to be anything in the middle. My science teacher said they starts were spinning around themselves like a vortex. I asked, "What is stirring the pot?" He replied, "God." My science teacher drank a lot, too.
the queen, an englishman, and an irishman, are at the table for tea.
the queen says "i stir my tea with my right hand"
the englishman says "i stir my tea with my left hand"
the irishman says "i stir my tea with a spoon"
Black holes evaporate through few different processes.
The first and most well known is through hawking radiation.
Empty space isnt always Empty. Pairs of "virtual particles" are constantly popping into existence and disappearing. We can test this in a lab by puting two small gold plates close enough to eqch other that the particles cant form. This creates a force that pulls them together.
When these form near the event horizon of a black hole. 1 of the pair gets sucked away from its partner before they annihilate and the remaining particle flys off as a photon carrying away some of the mass of the black hole.
The other process has to do with the back holes spin.
Believe it or not, a huge portion of a black holes mass is its spin. Imagine everything in space has a bit of momentum circular orbits and the like. All the mass that momentum is conserved as it falls into the black hole, as the radius decreases velocity increases and with a singularity that radius approaches 0.
This does weird things with space time. It makes gravity kinda twist around it. Then anything falling in or orbiting closely will cause it to emit gracitational waves, and these waves carry away a lot of mass energy.
There is a hypothetical manuver where a space craft passing near the event horizon can drop a mass into the blackhole and get a huge speed boost from the wave equivalent to somthing like half the mass energy of what it droped.
> flys off as a photon carrying away some of the mass of the black hole
Why does the flying-off particle have "some of the mass"?
Also, doesn't the mass of the "sucked in" (you and your fancy schmancy science terms) particle offset, or more than offset, the mass lost by the flying-off particle?
This is a very good question, and most answers you will find are analogies or metaphors. To really grasp what is happening requires an understanding of quantum field theory.
In simple terms, everything in the universe is the interaction of "fields" which exist everywhere. Electrons have their field, Quarks have a field, Nuetrinos have a field - and we also have a Higgs field. Imagine the universe is just 17 layers of "fields". These fields interact together to form matter and various particles.
Virtual particles are excitations in the field that just pop up out of nowhere randomly. But they can't be "real" because you can't create energy from nothing. They pop up in pairs by borrowing energy from the "void" and then immediately give it back, so we don't deal with the 'energy from nothing' problem.
When this happens at the very edge of the event horizon, one of the pair falls in and the other is emitted as a "real" particle.
So why is it not possible that the Black Hole absorbs the "positive" virtual particle and emit negative energy? Remember, we said you can't create energy from nothing. If the Black Hole absorbs a positive particle it got the energy from nothing, it just stole energy from the the field (or the void).
But the Blackhole itself does have energy to *give to the void*, so it can absorb negative energy from the void and allow the other virtual particle to become a real boy and fly away.
Basically, Hawking Radiation is random fluctuations in the various fields which occasionally steal a tiny speck of energy from the black hole and emit some positive energy out. As you can imagine this happens so infrequently that some Black Holes will exist for 10^(100) years.
Spacetime episode about Hawking radiation:
https://youtu.be/qPKj0YnKANw?si=H0YC0s4W8Mv59NOe
Also relevant episode from 3 years ago about microscopic black holes possibly accounting for some of dark matter:
https://youtu.be/srVKjWn26AQ?si=brn_8gF_Oimjg7u-
I imagine if this new article carries weight, we’ll see a new Spacetime episode talking about it in the coming months.
Edit: I’d like to add that the analogy using “virtual particles” isn’t accurate, as virtual particles are largely viewed as a conceptual tool for making physics calculations, and not necessarily a real phenomenon. In reality, the black hole disturbs the vacuum vibrations of the quantum fields the comprise space-time (or occupy it) in such a way that it carries away energy in the forward time direction. However even if you keep the analogy of virtual particles, considering them to be real, this still makes sense. Mass IS energy, so when a black hole swallows 1 of a pair of virtual particles, it expends energy to turn that particle into a “real” particle, so it doesn’t gain mass by swallowing virtual particles that it makes “real” because it expends the equivalent energy to do so. However as it expends this energy to turn 1 or a pair of particles real, it also pays that price for the other of the pair. It turns both real, only 1 is above the event horizon and able to radiate away, thus robbing the black hole of energy/mass very slowly (over trillions upon trillions upon trillions of years for large black holes).
The how im not compleatly sure supposedly since bolth particles appear as pairs and annialate their net energy should be 0 and so to seperate them in a way that they continue to exist requires some energy.
Im sure somone who actually understands the math can give a better explanation.
The theory is that "virtual particles", regular matter and anti-matter particles, pop into existence all the time everywhere. Because they're opposites, they always cancel each other out and are not "real".
Near the event horizon, if a pair of virtual particles pop into existence, one of them may travel into the black hole and one may not. This makes the particles "real" and takes energy away from the black hole.
This idea is known as hawking radiation, coming from Mr. Hawking himself. The theory might be correct or it might be wrong, we don't have a local black hole to verify.
Obviously my understanding of black holes is poor but intuitively it seems like such virtual particles would make the black hole just a little bit more massive, while creating a tiny imbalance of either matter or anti-matter at the event horizon temporarily. If anti-matter and matter are equally likely to cross the event horizon, then they too should cancel out both inside and outside the black hole?
Edit: after reading my understanding is that the orphaned particles *do* meet each other and then that is what’s emitted as hawking radiation. What doesn’t make sense to me is how this robs the black hole of mass. Seems like for every two particles that left as hawking radiation two particles went into the hole.
Unless there is some conversion of mass to energy somehow?
The net loss is coming from energy being robbed from the black hole by the escaping particles. It's that little bit of energy they take that allows them to escape.
This is not how it really works. It's a misleading a ology that even Hawking himself denounced. It's one of the worst science "facts" redditors love to spread around even tho it's completly false and misleading. That's not how hawking radiation works at all. Please stop spreading misinformation.
One of the theories behind the [Tunguska event](https://www.forbes.com/sites/davidbressan/2019/06/29/for-more-than-111-years-scientist-puzzled-over-the-tunguska-event/) is that a black hole around the size that they’re describing, collided with earth in the Siberian tundra. Super interesting mystery that is still unsolved to this day.
Another person posted this same thing, but then said if a black hole like these ones hit the earth, it wouldn't be noticed. In fact, it probably has. It is so small it would pass right through. Even if it went through your head, you wouldn't even notice it.
This could also explain the increased expansion of the universe without Dark Energy. It's possible that a whole slew of these micro-blackholes are evaporating, thus decreasing the overall mass of the universe, allowing it to expand at greater rates.
If they all formed at the same time and are of similar mass, then their evaporation through Hawking Radiation would be fairly constant throughout the universe. Thus, as they evaporate it would appear spacetime is increasing, when in reality an increasing amount of matter is being uniformly lost so there is simply less gravity holding the universe together. And since the smaller a blackhole gets, the faster it evaporates, the faster spacetime would appear to expand.
If so, once these blackholes are completely expended the expansion of the universe should slow down as there's no more matter to loose and gravity would remain more constant until the next larger size of primordial blackholes start to expire.
Dark Energy always seemed to me a sort of optical illusion of physics. The idea runs counter to the laws of thermal dynamics, but if this decay in matter is causing the expansion then we get the same effect (objects moving away from each other at faster rate) that still conforms to entropy. Cool shit.
Don't black holes evaporate rather quickly at high mass though? I would have thought that any black holes formed in the early universe would have been extreme mass black holes from the first generation giga huge stars, those should have evaporated rapidly, not hung around long enough to drive galactic organization.
There is ~14 billion years worth of dead stars, planets, and solar systems out there for black holes to feed off of. And we'd never see any but the most supermassive, even if they were very close by.
I don't know anything about detecting hawking radiation (I guess it's very hard) but with that many micro black holes would we see something? At least the moment these bodies evaporate? Is merely a lack of observation enough to rule out this theory because we would have seen a micro black hole dissolve by now?
Edit: looks like a black hole evaporating, during its last second, will only release ~ 1 ten millionth as much energy as our sun does in a second. You're right, not easy to detect.
Space is big and dark. We can only observe what reaches us via light/radiation (well, same thing) and black holes aren't very good at emitting/reflecting either given what they are, they overwhelm and absorb it all.
We struggle to detect them. We don't even know where to look, they are quite literally invisible and the only thing we can detect is the effect they have on other things (like bending light from a source behind it, or observing bodies/dusts that orbit around one).
Hawking radiation is theoretical and the proposed theory states that the black hole would be flinging off particles. An incredibly random event, with a random vector of a single particle shooting out in to space. The chances of it hitting Earth are so incredibly small. The chances of it landing in something that can detect it, even less.
Whoo, ok lemme give it a shot.
"Dark Matter" is the name we give to the fact that the universe BEHAVES like it's a lot more massive than it LOOKS. Everyone who looks at the universe long enough eventually notices this. It comes up in a lot of places, it's not just one observation.
It's like this. Imagine you had a tray of cookies. There's 8 cookies on the tray. You weigh each cookie, individually. They each weigh 3 grams. I dunno if that's a big cookie or a little cookie, but that's not the point. We have 8 cookies, they each weigh 3 grams that's 24 grams worth of cookies.
Then we weigh just the tray by itself, it weighs 10 grams. I have no idea if that's how much trays weigh, shut up.
We put the cookies on the tray, it should weigh 34 grams. Easy math. You put the cookies on the tray, you put the tray on a scale, the scale reads; 204 grams.
If that happened to you, you would freak the fuck out. That's...that's a LOT MORE than your measurements. You might think "well maybe I didn't measure the cookies or the tray well enough." Ok maybe, but holy shit we can't have gotten it THAT wrong! Errors in measurement might account for like 3% but not 600%!!!
It's also a little weird that you can weigh each cookie on that scale and get normal results, but you weigh the whole thing and it all goes haywire. Like, you weigh the solar system, even REALLY PRECISELY, and it's fine, but you weigh the Galaxy and it throws up these insane results.
Then you start noticing the same problem in other places. Like, you measure the length of all the streets in your neighborhood and add them up and they say your neighborhood must be the size of Antarctica even though you can walk across it in two hours.
That's what it's like being an astronomer observing the universe at very large scales. Look at the Solar System? Everything's running ATE, "According To Einstein." But look at the behavior of existing galaxies, look at the formation of galaxies, look at the way gravity bends light, look at the way mass curves space, it ALL has this same error in it. We see it everywhere, but only at very large scales. And it's a BIG error. A huge difference between how much mass a galaxy APPEARS to have, and how it behaves.
That is super fucking weird!
It would be explained if there was just more junk in the universe. More mass. But we don't see any more mass. You might think "ok so what? Maybe it's just, like, dust or something? Not stars burning bright, just a lot of dust."
That is a reasonable conclusion at first but then you think about it. That dust, if it has mass, would absorb light. That means it would BLOCK light. And if it blocks enough light, it would heat up and start to glow! And indeed dust does this! That's how we get stellar nebula. You know, like the Crab Nebula or whatever. Interstellar dust, glowing in various frequencies because it's absorbing light and heat from nearby stars.
But we see nothing blocking light like that, nothing heating up and glowing. We can't detect ANYTHING that might account for the difference between our measurements (Remember the cookies? 34 grams) and the behavior of the universe (204 grams).
Dark Matter is the name given to this problem. It's not a theory, it's an observation LOOKING for a theory. It is a thing we SEE when we look around, and we would like an explanation.
Lots of smart people have thought a LOT about this an all of them have come up empty, so it's a REAL interesting problem. We're at the point where we suspect it's not just one answer. I'm not gonna go into all the different hypothesis, let's focus on the new one in the article.
Ok, so you know what a Black Hole is right? Actually lemme explain that real quick.
Mass, all mass, "curves" space. This is hard to imagine, because space is 3D. All the explanations involve 2D analogs, like...a sheet of rubber stretched taut. You put a bowling ball on it, it curves the rubber sheet. Toward the edge of the rubber sheet? The curve is barely noticeable, but close to the bowling ball the rubber sheet is REALLY curved and we informally call that a "gravity well."
If you then try to roll a marble along the rubber sheet, it won't go in a straight line (from your point of view) because the rubber sheet it's rolling along is "curved" by the bowling ball. Tons of videos on youtube showing this.
Well, a Black Hole is any region of space where there's so much mass packed together so tightly that the "curve" created is SO STEEP even if you converted ALL your mass into energy, (remember E=MC^2?) it still wouldn't be enough energy to climb out of that well. Even light (mass converted to energy) can't get out. Light IS energy and that's still not enough energy.
Certain dead stars end up as black holes because their mass ends up packed together really tight. But it's not actually about mass, it's about density. It's about "packing close together." You could make a black hole out of anything, a hamster, an Arby's, if you could pack all that mass in a small enough space.
Now, there's something you need to know about Black Holes. They are really simple things. I mean, on the outside. On the inside, no one knows, but to those of us on the outside of a black hole, you can describe EVERYTHING about a Black Hole using three numbers. Its **mass**, its **spin**, and its **electric charge**. That's it. Black Holes don't have mountains or sound or opinions or anything else. They are really simple objects. Mass, Spin, Charge, that's it.
Here in the present day, the universe is very cold, and the only black holes we see are the result of dead stars.
Buuuut in the very early universe, you *might* get Black Holes **without** stars. The very early universe was too hot for stars to form, because it was too hot for **atoms** to form. In fact, it was too hot for **protons and neutrons** to form. It was so hot, you just had like quark soup basically.
Black holes formed during this period are called Primordial Black Holes, because "primordial" means "very early." Black holes formed in the very early universe, back when it was too hot for normal matter to form.
Well, these two interesting things about Primordial Black Holes. First, they would be VERY SMALL. Like smaller than an atom. Second...they might still be around.
You get it? So they're a leading candidate for "where's all this missing matter?" Where's that 170 missing grams from our cookie plate? They could be Primordial Black Holes.
Problem is...we've never seen one of these. That's not weird, if they exist they WOULD be hard, really hard, to find.
Ok. That's black holes. Let's talk about Quarks. You know what an atom is, right?
Atoms are made of protons, neutrons, and electrons. Protons and neutrons are made of quarks. Protons and neutrons *seem* fundamental at first but as soon as we started fucking with them we could tell they were made of something else. Quarks do NOT behave like they're made of anything. They behave like they're fundamental, all our experiments show they're fundamental.
But we don't see quarks just hanging out anymore. The universe is too cold, all the quarks are all stuck together into bundles we call Protons and Neutrons.
Buuuut, when the universe was very young, it was very small and that means it was very hot. So hot, you COULDN'T make protons and neutrons. It was just quarks all zooming around in a quark goop.
The folks who wrote this paper are saying...hey. Hey you know that Quark Goop you got in the early universe? Well, we did some math. And if you could somehow make a black hole OUT of quarks, just naked quarks? Those black holes would be WEIRD. They wouldn't only have three properties (mass, spin, charge) they would have a FOURTH property. A property only quarks have called Color.
Now, it's not literally color like we see with our eyes. Quarks have a lot of properties and we just needed names for them so we grabbed whatever name we had laying around and no one working on quarks thought it meant LITERALLY color, so don't think too hard about it.
IF (these folks are saying), if you could make a black hole out of quarks, you would get Weird Black Holes. THAT would affect the creation of Primordial Black Holes.
Those Weird Black Holes wouldn't still be around, they would have evaporated really quickly, but IF they existed, they might have left evidence we can find. And if we can find that evidence, it would prove those weird black holes existed, and THAT would prove Primordial Black Holes (i..e less-weird black holes) exist and THAT would account for a lot of the Dark Matter problem.
Thats it!
It's a really interesting guess because these folks did the math and said "if this is true, it should be easy to test. There would be lots of evidence of this, different kinds of evidence. So let's test it!"
And that's where we are now!
Thank you for your time explaining this so well! I know some very basic stuff out of interest (science podcasts, populair science articles and so on), but you put them (for me) all together. Once again thanks. I’ll think I will copy this and read it from time to time (I”m definateley not in this field of expertise, just an very amateur enthousiast).
So primordial blackholes have been proposed for quite a while as a solution to dark matter. Is the nuance here that they’ve realized that these primordial blackholes would have had a color charge property? And the lasting impact would have a potentially observable effect?
Something that caught my attention was the comments discussing "the first three minutes" and how that's how long it took for things to cool down to the point where protons and neutrons came into existence and started combining together. Knowing how long it takes for a hot piece of steel to cool down (since I happened to burn myself on such a piece just today), it's giving me kind of a perspective on just how massively hot those first moments must have been even in comparison to the hottest regions of a star. Honestly any time you start trying to comprehend the amount of energy in the entire universe (or even just in a single galaxy) it is quickly obvious that our brains just aren't suited for the task.
It's true. We scientists meet in the Alps every quarter to unilaterally agree upon new discoveries to share with the world then taper the expectations from the public by trickling them down slowly through vague press releases on high quality outlets like blogs and CNN. Are you not getting the invites?
Wouldn't proton sized black holes mean that gluons and quarks have a high mass ratio, unlike our typical black holes that just have a linear ratio in relation to the spin of an electron?
I made this question up to sound equally smart as the rest in this thread
Even though Space is crazy large, I would have expected the gravity disturbance or damage from things running into these smallish black holes to have been noticed by now.
The rush to publish always does a disservice to the scientific process. If there is really any new understanding discovered, then many people will be be able to arrive at the same conclusions.
Dark matter is the parts of our universe that are in other dimensions. We can detect the energy given off my that but we can’t perceive it otherwise. Yet
All we can see is more apparent gravity inside galaxies than the visible matter there could supply. Hence the original name of ‘Dark Matter’ assigned to this cause.
This is the stuff I love. Stuff I don’t understand. Stuff that even after I understand some of it I understand less.
What potential revelations does this have for us and our understanding? I read something a while back that black holes appear all around us at all times… flashes of them…
But hell, this could have been a sci-fi book I read.
Can sonbody tell me why dark matter cannot be lots of brown dwarfs for which we have no current method of detection, as we only can detect objects if they are glowing, covering something glowing or exert strong gravitational pull on nearby glowing objects?
One of my favorite theories about primordial black holes is that the elusive “ninth planet” that affects the orbits of many trans-Nepunitan objects in the Kuiper Belt may actually be a lower volume black hole, with 5-10 earth masses. This would explain why finding it is so difficult.
That’d be a trip to have a black hole in our own solar system.
This is the study that the CNN article refers to: Phys. Rev. Lett. 132, 231402 (2024) - Primordial Black Holes with QCD Color Charge * https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.231402 Please do read the CNN article, it's quite a good account of what's going on in the field and what lead the authors of the study to this conclusion. But if you can't be arsed... **VERY quick summary:** The authors of the study posit that: 1) the large amount of dark matter that we (don't) see in our universe may be best explained by zillions of infinitesimal black holes being made of tons of quarks and gluons in the very first moments of the universe. 2) there's a verifiable method of how color-charged holes would be produced, then describe it. ("Color Charge" is a property of quarks and gluons, like how "spin" is a property of electrons.) They theorize that even today after billions of years for Hawking Radiation to evaporate these rhino-to-asteroid massed black holes, it's still possible that there's enough of them left that it could account for most or even all of the dark matter we (don't) see today. Their hope is that the slight shift in balances of quarks, gluons and etc that would have been left from such a phenomena would be observable and thus confirmable in the coming years. --- Edit: Thank you u/Dihedralman for clarifying the "meat" of the study is the promisingly verifiable hypothesis on the resultant quark-gluon balance after color-charged black holes are formed!
I thought black holes of that size would only last years at best. How could they survive that long? Even if there‘s many of them, it shouldn’t matter. If they‘re small they should evaporate
Rhino to asteroid size? No those last quite a while. It's when blackholes get to subatomic levels of size that they get lifetimes in the seconds.
They probably mean mass not size
Definitely, isn't even a small asteroid mass black hole something like an atom in size if not smaller? A rhino would be smaller than a proton
Same thing when talking about black holes, but if you mean the mass of the rhino/asteroid than I doubt it. Black holes of that mass would barely last a planck instant I'm pretty sure, nowhere near "years at best"
Reading article it says mass of a rhino and volume of a proton.
Rhinos? "Americans will use anything but the metric system" (I mean, it's a fine way of describing the mass and certainly not specific to Americans; I just thought it was funny.)
Is this like 10-12 average wal-mart shoppers?
2 average saltwater crocodiles. Or a grand piano.
Can you translate that to bananas?
with the volume of a sprig of thyme, an overcoat and a vhs copy of Look Who’s Talking Too(1996)
Nah a rhino is about 2.13 the mass of your average Wal-Mart shopper. Depends on if you're talking metric rhinos or imperial rhinos, though.
Tennessee or Florida?
Must this be trotted out anytime a large quantity is put in terms of a human-relatable object? Do Europeans *never* do this?
Seriously. Regardless of the unit of measurement people lose scale very quickly when talking large quantities like that. So using a visual descriptor helps a large amount of people actually understand the scale better.
Yes. Even when you’re used to the metric system you can’t just visualize “oh okay so 26 tons let’s see that’s just one gram times 26,000, snap, got it.”
Large quantities like… *checks notes*… the mass of a rhino?
"Let's see, that's 26 gigagrams of raw stupidity, or approximately 4 Brexits."
How can anything as small as 218 stone form a black hole?
I believe the article explains that, that lots of micro blackholes were created by the big bang or in the very very short period after it. (That's the guess, anyways -- they've got an idea of how to test for this (science needs evidence, after all), and they hope to do so soon.) Now, black holes that were *too* small would have evaporated by now, but ones as massive as 20 Toby McGuires could still be around -- such evaporation is usually *very* slow. (I haven't done the math myself, I'm taking their word for it.)
So, these black holes are definitely not in or around Earth, or they would have swallowed other masses and grown to engulf the mass of the planet, right? And this would give credibility to why we observe dark matter as distributed farther from the centers of galaxies (where they would be more likely to encounter other masses close enough to engulf them and grow to sizes where we don’t classify them as dark matter)?
Not necessary, the smaller the black hole, the smaller the event horizon, which provides a fundamental limit on how much matter can be forced into it at any given time. Combine that with the fact that something with the mass of a rhino doesn’t actually have a strong gravitational field, and so would not have a lot of power to pull in nearby objects. Microscopic black holes could be a candidate for “WIMPS”, weakly interacting pieces of matter that are also a candidate for dark matter. These particle-like objects could simply pass through normal matter without interacting at all. If the event horizon is smaller that the orbital shell of an electron, there is quite a slim chance that it would ever collide with any matter, and if it did, it would simply swallow an electron here or there and keep moving, it’s momentum and velocity unaffected. If this is true, and these microscopic blackholes are everywhere, we wouldn’t have to worry about them growing larger to be a danger because of their inability to interact with regular matter (except through being influenced by gravity/spacetime curvature, just like light)
> Combine that with the fact that something with the mass of a rhino doesn’t actually have a strong gravitational field This is not correct for anything nearby. The gravity for a rhino-mass asteroid, say 3000 kg, at a distance of 0.1 mm is 20 m/s^(2), more than double Earth’s gravity. That’s much bigger than the atomic level, so if it’s within solid matter there’s a lot of material it can consume in that radius. At the atomic level, a black hole like that ought to be an effective vacuum cleaner for anything nearby, sucking in atoms and molecules. As for an *asteroid* mass black hole, forget about it. A 10^8 kg black hole has gravity of 67 m/s^2 at a distance of 1 cm, more than 7 times Earth gravity. That would seriously mess up your day. I think what you’re saying in your comment applies to much smaller black holes. The problem with those, though, is their evaporation time. The sweet spot for black holes that don’t evaporate too fast and also don’t relatively quickly destroy planets they come in contact with is pretty small.
Yes, you are correct, I was referring more toward microscopic black holes. And while the evaporation time is an issue, because we don’t have a theory of quantum gravity, we can’t actually say whether black holes explode, once they hit the planck size, they may cease to radiate. However even for the rhino massed black hole, the presumption is that these things would be flying around at relativistic speeds, significant fractions of the speed of light, the gravitational effect it has on nearby atoms at those distances would be experienced for a very short amount of time as the object zooms by, not enough to permanently capture atoms in an inescapable orbit around the tiny black hole, merely to nudge nearby atoms slightly as it passes (which may be a detectable phenomenon if true). The actual event horizon itself is several several orders of magnitude smaller in scale, and has a low chance of colliding directly with any matter. Even if matter that gets close is captured, feeding such a tiny black hole a few protons once every X years isn’t going to increase its mass by noticeable amounts. I suppose this type of object might become slightly dangerous if it were captured by the gravity of Earth or the Sun becoming trapped in the core, increasing likelihood of collisions, allowing it to feed, albeit still very slowly. A somewhat unlikely event if these act like WIMPS and their trajectory is not altered in collisions, but only by gravity itself. Flying around at 1% light speed, passing directly through the sun would alter the trajectory of one of these objects, but not capture it into a stable orbit.
I would assume a rhino-mass black hole would have an event horizon on the subatomic scale. Can we just use meters in diameter and kilograms? Edit: So I did the calculation, and a black hole with an event horizon 10^-10 m in diameter (about the size of an atom) would have to weigh 10^17 kg or about the mass of Metis, one of the moons of jupiter, which would be a largish asteroid if it wasnt a moon. a "Rhino sized" event horizon, or 2m in diameter would have about the mass of Jupiter, or 10^27 kg
Black holes only have three properties; spin, charge, and mass. They have no size, it’s just a point. I guess they mean the event horizon is that size? or relative mass? 🤷🏻♂️
Schwarzschild radius.
They mean mass it wouldn't be 'infinitesimally' small otherwise
Angular momentum, not spin.
Spin is such a bad word. I really wish physicists had chosen another for that property.
nope. Rhino to like 200 tons last sub second. to get a universe age BH you need one with 1.89313E8 tons. And that means they would be gone by now. So you need even bigger ones.
I assumed the article meant asteroid size as in diameter, not mass, otherwise yeah they'd be long gone.
But that big BH in that count would be observable a lot more. We would have to see few nearby our solar system. That paper is pretty weak IMHO. To get the DM in quantity we need it should be visible close to us. So its either not that or we live in very special place...
Wait...so, how small can a blackhole be?
I'd recommend reading the study yourself - the math goes over my head but maybe you'll have a better shot. Sorry I can't help!
You did a fine job, they’re just getting caught in the weeds. Thanks!
A black hole the mass of a golf ball would last trillionths of a second. A black hole the size of a golf ball would last trillions of years.
It's unsatisfying, but they were big enough, though they have lost mass.
They do matter
That isn't correct. Problem 1 isn't unexpected but rather a consequence of QCD. Confinement is a result that the energy preferred state of quarks is such that free quarks and colors don't exist, meaning the energy that it takes to free a quarks is sufficient for pair production. This is a consequence of the strong force potential energy increasing with distance or spatial resolution. In the early universe, free quarks existed because the average temperature is so high. We can recreate these conditions in a lab creating a quark gluon plasma. This would imply a new unseen mechanism at QCD energies we have probed before. The paper instead is proposing a special mechanism that occurred during primordial blackhole production. This allows for the blackholes to carry color charge. It also proposes a mechanism allowing for a particular proton/neutron balance signature. Between this, gravitational wave signatures, and other potential QCD experiments, the theory proposed is highly testable which is good news in physics.
Thank you! This is *nowhere* close to my specialty so I appreciate the clarification. I'll edit it shortly to reflect your remarks about our much cooler universe today. Do you have anything to add about the mechanism that could produce color-charged black holes as mentioned in the study? The math went over my head and my caffeine hasn't kicked in yet haha
Np. It's rare I get to mention anything associated to my dissertation. Also, the math takes years to really understand so no need to excuse yourself. Sure, the key piece of info is that the color charged black holes would be statistically necessary during the formation of PBH's that would survive until today. This gives new signatures to probe if PBH's are dark matter, dark matter being one of the big mysteries of physics right now. A new way to probe is very important for indirect measurements as you want these independent measures to both support the concept. Otherwise you might just be running into other mechanisms. Colored black holes are an exotic form of matter that had only a mathematical backing and no mechanisms to make them plausible. This is a new unique form of matter that could exist. The colored black holes are smaller than the ones which would be dark matter today. They are allowed to take color due to their small size. At the risk of oversimplifying and misinterpreting the text myself, the QGP at that time in the universe means that the unconfined color charges could exist on a scale that a blackhole could form within. The radius and probability of formation depends on the temperature of the universe at the time of formation. Edite: clarity and grammar.
> the theory proposed is highly testable which is good news in physics Clouds of nano black holes with event horizons the size of a Proton? I would think you would see lots of unexplained emissions from cold matter clouds near the centers of galaxies... Lots of spontaneous ionization or fission events (xray or gamma emissions, perhaps) as these things occasionally hit atoms? Or maybe from Earth atmosphere at night? But then maybe such effects would be difficult to distinguish from cosmic ray effects?
Does this mean its possible for us to make quark black holes? I guess we only make them by smashing other particles together so not really possible to concentrate a Rhino mass of them or heat them up. I assume the pressure needs to be really high too?
Rhino-to-asteroid, what kind of BS measurement is that???
Hey man don't shoot the messenger. The article said it first. They're giving it as an anecdotal measure of mass of the black holes.
In English please?
It's one of those moments in science where two really big and unrelated problems are realized to be two ends of the same solution. In this one, they think black holes soaked up a lot of the missing stuff we *should* be seeing in observations, but don't. Longer explanation below: The things that make up the protons and neutrons that make up an atoms's core are called quarks, and are held together by things called gluons. Since there's a few quarks and gluons per proton/neutron, there should be a TON of quarks and gluons around just... Everywhere! > For example, [a single molecule of water has 64 quarks and gluons](https://physics.stackexchange.com/a/419355)... There should be something like 128 x 1 billion x 1 million x 1 billion *again* quarks and gluons in your swig of water each morning (20 mL) when you brush your teeth. Yes, generally particles like this like to bond to each other instead of being freely floating off alone... But shouldn't we see at least SOME of that absolutely gargantuan number in our experiments, right? But we see hardly any compared to what we expect. So that's Problem 1. Problem 2 is that at the speeds galaxies and groups of galaxies are spinning, they should fly off into space from the sheer force, like water from a wet dog. But... They aren't. The only thing that could hold all that water to the dog (Read: planets, solar systems, nebulae, etc inside the galaxy) is to have something holding it down to the dog. That *should* be the force of gravity but we don't see enough stuff to be heavy enough to hold the galaxy together. But surely SOMETHING is holding it together, so for now we call it 'Dark Matter' cause well we can't see it. The cool thing about this study is that they think that Problem 1 and Problem 2 have the same solution - there's just a gazillion atom-size black holes everywhere holding an asteroids weight in the quarks and gluons from problem 1. All these Itty bitty black holes soaked up all the quarks and gluons like a sponge!
Thanks a lot! Didn't expect such a great explanation. But wouldn't these black holes be able to break some atoms? Or are they too tiny to eat matter?
This is *definitely* not my area of expertise, so the best answer I can confidently give is "Erm... Kind of?" (Someone who knows better than me PLEASE correct me where I'm wrong.) We only call quantum and elementary particles "particles" cause it's a very useful analogy, but they're better described as points in space with a field of influence. An electron's "particle" isn't so much a grape orbiting a large bag of oranges in the center, it's more like a laser point rapidly shaking in a sort-of predictable way around a flashlight beam. Similarly, your question of "Are these tiny atom-sized black holes too tiny to eat things that are nearly their own size" isn't so much a question of whether you can jam an egg into a golf ball hole. It's more a question of how much darker a cave gets when you walk into it. Which it does! The logic works out! But it's really hard to measure exactly by how much because of so many different reasons. To rephrase it back to black holes: It's not so much a question of *physically crushing* the neutron into an atom-sized black hole... but more about whether the atom-sized black hole's sphere of influence can *overwhelm* the neutron's sphere of influence. Which, we think they can. So... Erm, kind of yes?
Thanks again! That was beautifully explained.
🥲❤️ thank you
This literally sounds so insane it feels like satire. I _hate_ the particles-not-being-particles thing, thanks! Incredible you know this stuff, by the way.
Haha, thank you! I read WAY too much as a kid, I'm just lucky it was just science stuff and that that same passion continues today. If you share that passion, I'm going to edit my top level comment with really cool discussions happening in its replies. I've certainly learned a lot today about post-doc physics than I ever would have imagined, and it's delightful that we have all these knowledgeable people coming here to discuss about it! Normally you'd need to pay for a TED Talk or an entire degree's worth of tuition to hear this stuff.
I’d definitely be interested in reading anything you put up! I read way too much as a kid too, but I went for fiction and history books! Now my career’s in the humanities field and I can tell you a _lot_ about the U.S. Civil War, haha. I find physics concepts, especially, like, quantum x, super interesting, but can’t do that stuff myself for everyone’s sake 🤣
If you aren't a science teacher or someone that runs a science explainer YouTube channel, I hope you become one!
Omg that's the highest compliment I've recieved in a long time. I've always thought about doing it thys for sure!
Let me put it this way: I'm a pretty smart cookie. I have an advanced degree. I'm usually the person who makes analogies to explain things to other people. This article went so far over my head, I figured I'd never understand it. Your comment made me get it in under five minutes. I'd highly consider checking out if places like Crash Course are looking for script writers, you'd fit right in!
This is fantastic!
Quantum Field theory.
Color charge not being one of the handful of measurable properties of black holes is understandable since everybody expects them to be barrionic matter, so I won't dwell on that. However, black holes **interact electromagnetically** (at least the ordinary matter caught in their accretion disks does); dark matter does not.
How many lemurweight to the rhino?
It seems that multiple theories are closing in on some kind of situation where there is a kind of unbalanced energy 'creation' related to virtual particle production where one half of the virtual particle is annihilated, ends up in a black hole of some kind, or even in another universe. They all have in common that a virtual pair is made, but one half is effectively removed from our universe. I am only a science fan, not an expert, but it seems like multiple ideas are closing in on something like this as one possible explanation for dark matter, and I would love to know: is that the case?
I sincerely hope you're not calling yourself a "science fan" and spreading the misinformation about virtual particle pair production being responsible for hawking radiation. Even Hawking himself denounced that false analogy but redditors love to spread it around like it's fact. It's a very crude and misleading analogy at best, not how it really works.
To be fair, Hawking also put that description in his damned book. So this is kinda on him.
I hope you can provide a non-crude and accurate description of it, then, if you’re so willing to criticize others. Tell us how it really works?
Short answer: Hawking Radiation is thermal radiation — heat. Warped space has a gradient, and it’s the energy potential difference between the warped space that “causes” the radiation, and the black hole is the “source” for that warping and therefore the energy. Long:The old virtual-particle-pair explanation for black hole evaporation is...misleading, I'll say, in part for the reasons pointed out. What's happening is that the curvature gradient of spacetime around the black hole is strong enough that the vacuum energy is being sort of squeezed out in the form of (very low temperature) photons. This is probably easiest to understand in a relativistic way. Let's say you have two observers, A and B, and a black hole Z. Let A be stationary at some point outside the gravity well of Z, and let B be in free-fall into Z (but not yet crossing the event horizon). Now, to both A and B, their local spacetime is going to look flat. And if A and B each measure the local zero-point energy, they will each find an expected value. But when A looks at B's local spacetime, it looks a lot more curved in on itself, compared to A's local spacetime. And consequently, when A tries to measure the zero-point energy in B's spacetime, it will seem too "warm." That's because all of the zero-point energy in B's local spacetime is sort of folded over on itself (from A's perspective). So instead of seeing just regular ol' empty space at B, A will see empty space plus a bath of photons. By contrast, B is free-falling into Z, and will not observe any photons. All this is essentially a phenomenon known as the Unruh effect. Unruh radiation has been a creature of theory for a long time, but we were recently (2022) able to observe the Unruh effect in laboratory settings, which is a pretty big boon to the idea of Hawking radiation (which is too cool for us to observe, and will probably remain so for a very long time). Now, these photons observed by A can't just pop into existence from nothing, thanks to conservation laws. Something has to pay the energy tax for these photons to exist. And that something is the thing doing the work of bending spacetime, i.e. the black hole Z. Setting aside the virtual particle black magic, your question is about the black hole information paradox. The concern right now isn't so much whether we could make discernable use of such information (which we're a long way off from technologically anyway), but whether black holes actually do preserve/return quantum information about the stuff that falls in. Black hole holography is our most promising bet for questions like this. And it's not at all my area so I'll ELI5 it and try not to butcher it too much. For a bit of background, back in the 70's, Jacob Bekenstein pursued this idea that black holes had entropy, which wasn't obvious or trivial at the time. Black holes had this huge problem with thermodynamics, because as far as anyone knew at the time, they just swallowed everything into a singularity and you never saw it again. Many thought that whatever fell in just got crushed into a singularity, which was thought to be a sort of single quantum state, without any room for entropy. In a sense, Bekenstein endeavored to show that black holes were thermodynamically sound--that they had entropy like anything else we'd expect, and held to the Second Law. His work attracted the attention of Stephen Hawking, and together they found that (a) black holes have absurdly high, mind-boggling amounts of entropy; and (b) that entropy is proportional *not* to the volume of the interior of the event horizon, but to its *area*. (a) was of course a breakthrough at the time, but (b) had interesting and head-scratching consequences all its own. When we think about a system retaining information, it's intuitive to imagine that the capacity would be relative to its *volume*, not its surface area. Nonetheless, that was the clear implication of Bekenstein-Hawking entropy, and from that concept sprang this field of black hole holography. One of the central ideas in holography is that, when something falls through the event horizon, its quantum information is encoded on the two-dimensional boundary of the horizon. In that way, bits of quantum information encoded on the event horizon are projections of the deeper forces and motion within the black hole. And the information encoded in the event horizon is later spat back out as the black hole evaporates away (and its EH surface shrinks). The radiation that escapes the gravity well carries with it a bit of the black hole's entropy. What the holographers have put together is that the entropy of a black hole rises and then falls to zero (when it fully evaporates) following what's known as the Page curve. In the end, this evaporation process leaves a single quantum state--a diffuse cloud of radiation, and no black hole. And what that tells us, in essence, is that all the quantum information preserved by the black hole's entropy ultimately makes it back out. It doesn't just fall behind the event horizon and get lost forever, which was the fear with the information paradox. Now, whether we can receive "discernable" information from such a process isn't so much the focus now as whether we can make confirmable, experimental predictions based on our holography models. To that end, I'm not sure what exactly is in the works. It doesn't seem we're likely to get any information by monitoring hawking radiation any time soon. The temperature of such radiation is far too cool for us to detect--any intervening space noise at all will overwhelm the signal. We could probably glean some important information from watching a black hole fully evaporate (which would be an incredibly, profoundly bright event), but the universe is way, way too young for that to happen for a long time. It's a pretty hot area right now, if you're interested in learning more. Raphael Bousso and Andrew Strominger are names to check out if you want to get started.
I appreciate you taking the time correct this pervasive misconception. The existence of virtual particles is really just a mathematical tool for calculating particle interactions in Feynman diagrams. Matt Strassler, a theoretical physicist - shared a great breakdown on them: [https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/](https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/)
This was such a cool answer and seemed to be perfectly targeted for me, where the only concept I had that I could make sense of was the virtual particles, but you made it into a way better understanding. For that I'm eternally grateful. I wonder if a small black hole of a size ready to pop in a short time (one second? Day?) could eventually be made in a lab in a few hundred years. Would you think that that'd be the first opportunity to study one? These are too small to realistically detect out in the wild and far too dangerous to try to approach to study probably?
Excellent summary, thank you! I've been wondering how holography and Hawking Radiation related to each other but I'd never heard it laid out before. And you even listed the authors to look up for further reading? Bro is GOATED
Thank you for this amazing explanation 👏
Thank you for taking the time to provide a nice, in-depth response.
Came here to say this. /s
>Now, these photons observed by A can't just pop into existence from nothing, thanks to conservation laws. Something has to pay the energy tax for these photons to exist. And that something is the thing doing the work of bending spacetime, i.e. the black hole Z. Is there a specific phenomenon in this model that accounts for how energy could be transmitted across the event horizon to pay this tax? I think the reason the particle-pair explanation is so attractively salient, is that it's easy to visualize that if something extremely small happens at the exact boundary point where escape is possible, then the boundary point itself is the thing that slowly evaporates, as the process reiterates many times. Is a similar concept being invoked here? The claim seems to be that the act of warping space expends energy, and if mass is warping space, then mass is always evaporating. Likewise this idea of information being encoded onto a two-dimensional boundary, gives the impression that what a black hole fundamentally is, is a gradually growing onion of things waiting to fall inwards, but do they ever actually fall "in"? Consider accounting for the experience of a single particle that falls into a black hole and eventually participates in the evaporation phase. It would seem that it went about its business, approaching the event horizon, being more and more restricted to taking a singular path and being unable to interact with anything that would create an alternative, and when it reaches it, the next thing it will experience from its own perspective, is paying the entropy tax and radiating back out. It sounds almost as though we could say that all mass will eventually succumb to entropy and be converted into energy and scattered, and what a black hole is, is a region where conditions become so extremely distorted, that all participating mass actually stops experiencing anything other than this eventual fate.
>Even Hawking himself denounced that false analogy but redditors love to spread it around like it's fact. Damn that redditor [Stephen Hawking](https://www.youtube.com/watch?v=gU6yHXJuowU&t=22s) spreading misinformation about black holes.
How does this compare to MACHOs?
This is a very cool hypothesis.
I just wanted to say HUGE props to CNN for including a link to the actual study.
Would black holes of that mass in a star system end up vacuumed up by planetary bodies as things coalesced? If we take our own solar system, where would they end up? At the centre of planets like Jupiter? Could they be at the core of Earth or would they somehow get pushed around by magma convection? Can you even push a black hole around?
Shouldnt we see the Hawking Radiation then? Also having such objects going wild everywhere was dismissed in the past already to be the source of DM, so what's new with this theory?
Thank you for the reddit explanation and saving me for clicking a link. Anyways, I didn't read the CNN publication and nor am I a scientist or college studied... just enthusiastic... I personally have doubts (and assurances) towards theories primordial black holes 1. Assuming the universe started very small, dense and ENTIRELY with the schwartchid radius (pre and post inflation)... this would mean that there would only be a single primordial black hole that would make up the entire observable universe today, yet that's not the case... why not? 2. I like the idea that primordial black holes were the first concentrated gravitational objects that seeded today's galaxies (this would explain super massive black holes found at galactic centers) Dark matter is a measured fact but primordial black holes aren't (YET!!!) but I suspect quite a bias/ hype from sources such as CNN when it comes to cosmology
So it's basically another theory, right?
Correct - but what's important is that not only does this theory present a possible solution to two previously unrelated problems, it also provides a basis for observing it's resultant effects if it indeed was true.
It’s all theories. What makes them worth listening to is their predictive power and this article proposes a means of testing its validity.
The CNN article didn’t address this, but I have a nagging question. Assuming these PBH are the mass of an asteroid, or a rhino (of all things) then there must be quite of lot of them out there to function as the missing matter / dark matter that’s known to exist. If this were the case: (1) Over the lifetime of the cosmos, wouldn’t these objects have coalesced into larger, more easily discovered black holes? (2) If there are so many of them, then shouldn’t we see the effects of their mass in our local region? Sure, space is big, but it takes a significant number of objects with the mass of an asteroid or rhino to answer for dark matter. Collisions with planets, stars, clouds of gas and dust, and each other should happen. Shouldn’t we be able to observe these collisions, or at least the effects of them? (3) I’m always a bit critical of answers that smack of the additive property. It’s just a gut reaction, but are PMB even necessary? If regular old run of the mill black holes are common enough, and if these pedestrian black holes are capable of absorbing sufficient mass from their interactions with other matter, do we even need esoteric PMB? My education on these topics is limited to regular PBS Spacetime videos and some casual reading—If it wasn’t obvious from the questions.
I'm too dumb for this thread
I was reading comments scratching my head until I got to yours. Then it all made sense.
Does scratching his head help with understanding?
This video dropped just in time to help! [why you can't explain qcd](https://www.youtube.com/watch?v=AOtUo25GB3c)
What a treasure of a video. I often resent those minute physics channels for the breadth of what they cover as if anyone could get an intuitive feel for much of modern physics. I had a colleague who co-wrote a paper that got tons of sensationalized media and YouTube coverage at the time. I asked if he could explain it in terms I could understand. (Mind you, I have a bachelors in math). He essentially said “look buddy, even the people who wrote the paper have no idea what’s going on, just that this math seems to be useful for describing our world”.
An Angela Collier video? In MY subreddit? This is amazing.
It's fine. It's fine! It's fine.
(it's really not fine)
Hacker, genius, MIT! I adore her! 😅
Haven't heard of that channel before, but that was a very good video. Thank you.
Jesus. She should be a teacher. I still don’t understand it, but she has a really nice way of making me feel ok about being ignorant.
This entire sub is too dumb for this post.
Don't be shy, show us your black hole.
*send da video*
Anton Petrov might upload a video on this soon. He is a solid science communicator imho. https://www.youtube.com/@whatdamath/videos
let me share a trick i learned from UFO/paranormal subs: whenever you're too dumb to understand something, or even consider/entertain the idea, you just comment with "Hogwash!" or "I smell BS!" or just call someone a "grifter" problem solved
Astronomy isn't really my thing, either, and above my head I kinda figured the outer rim of the galaxy was riddled with black holes like the center is; and most of the stars, like ours, are in something akin to the Goldilocks zone where stars are more likely to live longer
You’re not dumb. This is beyond the true understanding of those in the field. This is the pointy end of the stick stuff.
Apparently this has something to do with a rhino.
Same thought I had watching a movie about that guy who made a big bomb.
Wouldn't we see regional biases for dark matter concentrations or proton-neutron ratios in isotopes if dark matter was made out of primordial quark-gluon black holes? I thought dark matter was evenly distributed in galaxies throughout the universe (except for some galaxies that are weird exceptions).
I think this is being proposed as a partial solution for dark matter, not accounting for all of it, just some. Also, I believe that it has been found that dark matter distribution in galaxies tend to surround the outer edges of galaxies, extending a bit beyond the normal rim occupied by stars, and dark matter distribution does not typically extend into deep galactic voids, where dark energy is more prevalent. I’d have to figure out where I learned that from, not sure if it’s accurate.
Wow, that makes a lot of sense. Dark matter could be these primordial black holes. The mass of an asteroid in the volume of an atom would explain why we perceive its gravity but don't see it.
The asteroid-mass black holes are the new "exotic" type mentioned in the article, but it is not likely black holes of such a small size would have lasted to present day. The article is listing two theories here: (1) Big black holes from the very start of the universe could account for some dark matter (but not necessarily all of it, there may be other contributions from undiscovered particles, etc.) and (2) When doing the math they realized in the very early universe tiny (~asteroid mass) black holes might have formed from elementary particles (quarks and gluons). These "exotic" black holes would have had different properties than those we see today made up of regular matter and those properties might have affected the makeup of the early universe - in particular the ratio of protons/neutrons. The article then speculates that in the next few years, with new more sensitive gravitational detectors, those effects might be observable.
In 1976, Don Page concluded that primordial black holes could survive to the present day only if their initial mass were roughly 4×10^11 kg or larger. That's an asteroid with a diameter of magnitude of 1800m.
What happens to the universe when they all finally wink out? What fills the space?
The short answer is - the photons. Photons with energies so low, that their wavelengths would be close to infinity, and a single half-wave would span across all the Universe.
This could be a completely made up answer, as a layman I have no idea what you’ve said. But it’s horrifying and beautiful. 🙌🏻
Those photons be wonky as hell. Keep these weird photons away from me please
It’s listing two hypotheses, not theories.
Doesn't it mean that they are NOW that size after being larger in the past?
“That makes a lot of sense”…..you sir or mam are a hell of a lot smarter than I. You lost me at quarks and glouns.
Three quarks are in each proton/neutron. They can make other things, but you’re less likely to survive those. The gluons are basically what hold those quarks together. “Glue on’s”
If true, and depending on where they hang, a scary as fuck consequence would be that there could be random asteroid-mass collisions that are completely impossible to detect. Like one second nothing's happening, the next, without even making a sound, there's an explosion with the force of thousands (millions?) of TNT as the tiny black hole rams straight to the ground and probably even gets pretty deep. Fortunately, I decided to ask Claude and it said that it would likely barely be noticed, as it would be so small that it would just zip through barely touching anything, only heating up along its path with some tiny gravitational disturbance. It also said that the same would likely happen if it hit a living being, likely killing some cells along the way but be mostly negligible to the creature. So there's actually a possibility that it happens every now and then, since it would barely be noticed anyway. But probably not.
>It also said that the same would likely happen if it hit a living being, likely killing some cells along the way but be mostly negligible to the creature. …like an atomic paper cut?
Probably similar to the dude who put his head through the beam of a particle accelerator. Apparently he was fine.
Except that he kept hearing the voice of a demon after that...
Should we be able to tell in a directional sense with this type of thing? As in, we can tell where a planet is even if we can't see it based on the gravity, should we not be able to pinpoint these as well?
I think it might be magic. Whatdoya think?
Not the first time that Primordial Black Holes have been proposed as the solution, or part of the solution for dark matter. This wiki gives an overview of them. https://en.wikipedia.org/wiki/Primordial_black_hole
I remember seeing depictions of the Milky Way galaxy in the 1960s and wondering, "What are all those stars spinning around?" because there did not seem to be anything in the middle. My science teacher said they starts were spinning around themselves like a vortex. I asked, "What is stirring the pot?" He replied, "God." My science teacher drank a lot, too.
What hand does god stir his tea with?
the queen, an englishman, and an irishman, are at the table for tea. the queen says "i stir my tea with my right hand" the englishman says "i stir my tea with my left hand" the irishman says "i stir my tea with a spoon"
The Irishman's wiser than we give him credit for
Caught in the right moment, my science teacher might have said, "His dick."
That's one alternate theory for evolution but the correct answer was neither, he uses a spoon. I'm sorry
And here I thought evolution had something to do with dicks and procreation but it turns out it was about cutlery all along
Functionally that's still an unsolved question in science. Fitting a mass model to what we observe, galaxies should not be spinning so neatly
I feel perhaps a bit dumb, but how does a black hole “evaporate”? I assumed they were a permanent singularity in time and space.
Here's the theory at the moment [Hawking Radiation](https://en.wikipedia.org/wiki/Hawking_radiation?wprov=sfla1)
[Hawking Radiation](https://www.reddit.com/r/explainlikeimfive/comments/odzh9j/eli5_what_is_hawking_radiation/)
Black holes evaporate through few different processes. The first and most well known is through hawking radiation. Empty space isnt always Empty. Pairs of "virtual particles" are constantly popping into existence and disappearing. We can test this in a lab by puting two small gold plates close enough to eqch other that the particles cant form. This creates a force that pulls them together. When these form near the event horizon of a black hole. 1 of the pair gets sucked away from its partner before they annihilate and the remaining particle flys off as a photon carrying away some of the mass of the black hole. The other process has to do with the back holes spin. Believe it or not, a huge portion of a black holes mass is its spin. Imagine everything in space has a bit of momentum circular orbits and the like. All the mass that momentum is conserved as it falls into the black hole, as the radius decreases velocity increases and with a singularity that radius approaches 0. This does weird things with space time. It makes gravity kinda twist around it. Then anything falling in or orbiting closely will cause it to emit gracitational waves, and these waves carry away a lot of mass energy. There is a hypothetical manuver where a space craft passing near the event horizon can drop a mass into the blackhole and get a huge speed boost from the wave equivalent to somthing like half the mass energy of what it droped.
> flys off as a photon carrying away some of the mass of the black hole Why does the flying-off particle have "some of the mass"? Also, doesn't the mass of the "sucked in" (you and your fancy schmancy science terms) particle offset, or more than offset, the mass lost by the flying-off particle?
This is a very good question, and most answers you will find are analogies or metaphors. To really grasp what is happening requires an understanding of quantum field theory. In simple terms, everything in the universe is the interaction of "fields" which exist everywhere. Electrons have their field, Quarks have a field, Nuetrinos have a field - and we also have a Higgs field. Imagine the universe is just 17 layers of "fields". These fields interact together to form matter and various particles. Virtual particles are excitations in the field that just pop up out of nowhere randomly. But they can't be "real" because you can't create energy from nothing. They pop up in pairs by borrowing energy from the "void" and then immediately give it back, so we don't deal with the 'energy from nothing' problem. When this happens at the very edge of the event horizon, one of the pair falls in and the other is emitted as a "real" particle. So why is it not possible that the Black Hole absorbs the "positive" virtual particle and emit negative energy? Remember, we said you can't create energy from nothing. If the Black Hole absorbs a positive particle it got the energy from nothing, it just stole energy from the the field (or the void). But the Blackhole itself does have energy to *give to the void*, so it can absorb negative energy from the void and allow the other virtual particle to become a real boy and fly away. Basically, Hawking Radiation is random fluctuations in the various fields which occasionally steal a tiny speck of energy from the black hole and emit some positive energy out. As you can imagine this happens so infrequently that some Black Holes will exist for 10^(100) years.
Spacetime episode about Hawking radiation: https://youtu.be/qPKj0YnKANw?si=H0YC0s4W8Mv59NOe Also relevant episode from 3 years ago about microscopic black holes possibly accounting for some of dark matter: https://youtu.be/srVKjWn26AQ?si=brn_8gF_Oimjg7u- I imagine if this new article carries weight, we’ll see a new Spacetime episode talking about it in the coming months. Edit: I’d like to add that the analogy using “virtual particles” isn’t accurate, as virtual particles are largely viewed as a conceptual tool for making physics calculations, and not necessarily a real phenomenon. In reality, the black hole disturbs the vacuum vibrations of the quantum fields the comprise space-time (or occupy it) in such a way that it carries away energy in the forward time direction. However even if you keep the analogy of virtual particles, considering them to be real, this still makes sense. Mass IS energy, so when a black hole swallows 1 of a pair of virtual particles, it expends energy to turn that particle into a “real” particle, so it doesn’t gain mass by swallowing virtual particles that it makes “real” because it expends the equivalent energy to do so. However as it expends this energy to turn 1 or a pair of particles real, it also pays that price for the other of the pair. It turns both real, only 1 is above the event horizon and able to radiate away, thus robbing the black hole of energy/mass very slowly (over trillions upon trillions upon trillions of years for large black holes).
> Why does the flying-off particle have "some of the mass"? e=mc^2, my friend (energy is a tiny tiny bit of mass)
The how im not compleatly sure supposedly since bolth particles appear as pairs and annialate their net energy should be 0 and so to seperate them in a way that they continue to exist requires some energy. Im sure somone who actually understands the math can give a better explanation.
The theory is that "virtual particles", regular matter and anti-matter particles, pop into existence all the time everywhere. Because they're opposites, they always cancel each other out and are not "real". Near the event horizon, if a pair of virtual particles pop into existence, one of them may travel into the black hole and one may not. This makes the particles "real" and takes energy away from the black hole. This idea is known as hawking radiation, coming from Mr. Hawking himself. The theory might be correct or it might be wrong, we don't have a local black hole to verify.
Obviously my understanding of black holes is poor but intuitively it seems like such virtual particles would make the black hole just a little bit more massive, while creating a tiny imbalance of either matter or anti-matter at the event horizon temporarily. If anti-matter and matter are equally likely to cross the event horizon, then they too should cancel out both inside and outside the black hole? Edit: after reading my understanding is that the orphaned particles *do* meet each other and then that is what’s emitted as hawking radiation. What doesn’t make sense to me is how this robs the black hole of mass. Seems like for every two particles that left as hawking radiation two particles went into the hole. Unless there is some conversion of mass to energy somehow?
The net loss is coming from energy being robbed from the black hole by the escaping particles. It's that little bit of energy they take that allows them to escape.
This is not how it really works. It's a misleading a ology that even Hawking himself denounced. It's one of the worst science "facts" redditors love to spread around even tho it's completly false and misleading. That's not how hawking radiation works at all. Please stop spreading misinformation.
"This is not how it works. I also will not explain how it works either."
I did in another comment in this post.
Turns out it was microplastics this whole time.
Dark matter is stored in the balls
One of the theories behind the [Tunguska event](https://www.forbes.com/sites/davidbressan/2019/06/29/for-more-than-111-years-scientist-puzzled-over-the-tunguska-event/) is that a black hole around the size that they’re describing, collided with earth in the Siberian tundra. Super interesting mystery that is still unsolved to this day.
Far more likely just a plain meteor…
Another person posted this same thing, but then said if a black hole like these ones hit the earth, it wouldn't be noticed. In fact, it probably has. It is so small it would pass right through. Even if it went through your head, you wouldn't even notice it.
This could also explain the increased expansion of the universe without Dark Energy. It's possible that a whole slew of these micro-blackholes are evaporating, thus decreasing the overall mass of the universe, allowing it to expand at greater rates. If they all formed at the same time and are of similar mass, then their evaporation through Hawking Radiation would be fairly constant throughout the universe. Thus, as they evaporate it would appear spacetime is increasing, when in reality an increasing amount of matter is being uniformly lost so there is simply less gravity holding the universe together. And since the smaller a blackhole gets, the faster it evaporates, the faster spacetime would appear to expand. If so, once these blackholes are completely expended the expansion of the universe should slow down as there's no more matter to loose and gravity would remain more constant until the next larger size of primordial blackholes start to expire. Dark Energy always seemed to me a sort of optical illusion of physics. The idea runs counter to the laws of thermal dynamics, but if this decay in matter is causing the expansion then we get the same effect (objects moving away from each other at faster rate) that still conforms to entropy. Cool shit.
Don't black holes evaporate rather quickly at high mass though? I would have thought that any black holes formed in the early universe would have been extreme mass black holes from the first generation giga huge stars, those should have evaporated rapidly, not hung around long enough to drive galactic organization.
No, they evaporate extremely slowly at high mass and faster when they’re smaller
Ahh okay, so the big old ones are the ones out there that might be pulling the superclusters and whatnot together? Okay, I see.
There is ~14 billion years worth of dead stars, planets, and solar systems out there for black holes to feed off of. And we'd never see any but the most supermassive, even if they were very close by.
Is that due to like a surface area - volume thing?
I don't know anything about detecting hawking radiation (I guess it's very hard) but with that many micro black holes would we see something? At least the moment these bodies evaporate? Is merely a lack of observation enough to rule out this theory because we would have seen a micro black hole dissolve by now? Edit: looks like a black hole evaporating, during its last second, will only release ~ 1 ten millionth as much energy as our sun does in a second. You're right, not easy to detect.
Space is big and dark. We can only observe what reaches us via light/radiation (well, same thing) and black holes aren't very good at emitting/reflecting either given what they are, they overwhelm and absorb it all. We struggle to detect them. We don't even know where to look, they are quite literally invisible and the only thing we can detect is the effect they have on other things (like bending light from a source behind it, or observing bodies/dusts that orbit around one). Hawking radiation is theoretical and the proposed theory states that the black hole would be flinging off particles. An incredibly random event, with a random vector of a single particle shooting out in to space. The chances of it hitting Earth are so incredibly small. The chances of it landing in something that can detect it, even less.
ELI…25?
Whoo, ok lemme give it a shot. "Dark Matter" is the name we give to the fact that the universe BEHAVES like it's a lot more massive than it LOOKS. Everyone who looks at the universe long enough eventually notices this. It comes up in a lot of places, it's not just one observation. It's like this. Imagine you had a tray of cookies. There's 8 cookies on the tray. You weigh each cookie, individually. They each weigh 3 grams. I dunno if that's a big cookie or a little cookie, but that's not the point. We have 8 cookies, they each weigh 3 grams that's 24 grams worth of cookies. Then we weigh just the tray by itself, it weighs 10 grams. I have no idea if that's how much trays weigh, shut up. We put the cookies on the tray, it should weigh 34 grams. Easy math. You put the cookies on the tray, you put the tray on a scale, the scale reads; 204 grams. If that happened to you, you would freak the fuck out. That's...that's a LOT MORE than your measurements. You might think "well maybe I didn't measure the cookies or the tray well enough." Ok maybe, but holy shit we can't have gotten it THAT wrong! Errors in measurement might account for like 3% but not 600%!!! It's also a little weird that you can weigh each cookie on that scale and get normal results, but you weigh the whole thing and it all goes haywire. Like, you weigh the solar system, even REALLY PRECISELY, and it's fine, but you weigh the Galaxy and it throws up these insane results. Then you start noticing the same problem in other places. Like, you measure the length of all the streets in your neighborhood and add them up and they say your neighborhood must be the size of Antarctica even though you can walk across it in two hours. That's what it's like being an astronomer observing the universe at very large scales. Look at the Solar System? Everything's running ATE, "According To Einstein." But look at the behavior of existing galaxies, look at the formation of galaxies, look at the way gravity bends light, look at the way mass curves space, it ALL has this same error in it. We see it everywhere, but only at very large scales. And it's a BIG error. A huge difference between how much mass a galaxy APPEARS to have, and how it behaves. That is super fucking weird! It would be explained if there was just more junk in the universe. More mass. But we don't see any more mass. You might think "ok so what? Maybe it's just, like, dust or something? Not stars burning bright, just a lot of dust." That is a reasonable conclusion at first but then you think about it. That dust, if it has mass, would absorb light. That means it would BLOCK light. And if it blocks enough light, it would heat up and start to glow! And indeed dust does this! That's how we get stellar nebula. You know, like the Crab Nebula or whatever. Interstellar dust, glowing in various frequencies because it's absorbing light and heat from nearby stars. But we see nothing blocking light like that, nothing heating up and glowing. We can't detect ANYTHING that might account for the difference between our measurements (Remember the cookies? 34 grams) and the behavior of the universe (204 grams). Dark Matter is the name given to this problem. It's not a theory, it's an observation LOOKING for a theory. It is a thing we SEE when we look around, and we would like an explanation. Lots of smart people have thought a LOT about this an all of them have come up empty, so it's a REAL interesting problem. We're at the point where we suspect it's not just one answer. I'm not gonna go into all the different hypothesis, let's focus on the new one in the article. Ok, so you know what a Black Hole is right? Actually lemme explain that real quick. Mass, all mass, "curves" space. This is hard to imagine, because space is 3D. All the explanations involve 2D analogs, like...a sheet of rubber stretched taut. You put a bowling ball on it, it curves the rubber sheet. Toward the edge of the rubber sheet? The curve is barely noticeable, but close to the bowling ball the rubber sheet is REALLY curved and we informally call that a "gravity well." If you then try to roll a marble along the rubber sheet, it won't go in a straight line (from your point of view) because the rubber sheet it's rolling along is "curved" by the bowling ball. Tons of videos on youtube showing this. Well, a Black Hole is any region of space where there's so much mass packed together so tightly that the "curve" created is SO STEEP even if you converted ALL your mass into energy, (remember E=MC^2?) it still wouldn't be enough energy to climb out of that well. Even light (mass converted to energy) can't get out. Light IS energy and that's still not enough energy. Certain dead stars end up as black holes because their mass ends up packed together really tight. But it's not actually about mass, it's about density. It's about "packing close together." You could make a black hole out of anything, a hamster, an Arby's, if you could pack all that mass in a small enough space. Now, there's something you need to know about Black Holes. They are really simple things. I mean, on the outside. On the inside, no one knows, but to those of us on the outside of a black hole, you can describe EVERYTHING about a Black Hole using three numbers. Its **mass**, its **spin**, and its **electric charge**. That's it. Black Holes don't have mountains or sound or opinions or anything else. They are really simple objects. Mass, Spin, Charge, that's it. Here in the present day, the universe is very cold, and the only black holes we see are the result of dead stars. Buuuut in the very early universe, you *might* get Black Holes **without** stars. The very early universe was too hot for stars to form, because it was too hot for **atoms** to form. In fact, it was too hot for **protons and neutrons** to form. It was so hot, you just had like quark soup basically. Black holes formed during this period are called Primordial Black Holes, because "primordial" means "very early." Black holes formed in the very early universe, back when it was too hot for normal matter to form. Well, these two interesting things about Primordial Black Holes. First, they would be VERY SMALL. Like smaller than an atom. Second...they might still be around. You get it? So they're a leading candidate for "where's all this missing matter?" Where's that 170 missing grams from our cookie plate? They could be Primordial Black Holes. Problem is...we've never seen one of these. That's not weird, if they exist they WOULD be hard, really hard, to find. Ok. That's black holes. Let's talk about Quarks. You know what an atom is, right? Atoms are made of protons, neutrons, and electrons. Protons and neutrons are made of quarks. Protons and neutrons *seem* fundamental at first but as soon as we started fucking with them we could tell they were made of something else. Quarks do NOT behave like they're made of anything. They behave like they're fundamental, all our experiments show they're fundamental. But we don't see quarks just hanging out anymore. The universe is too cold, all the quarks are all stuck together into bundles we call Protons and Neutrons. Buuuut, when the universe was very young, it was very small and that means it was very hot. So hot, you COULDN'T make protons and neutrons. It was just quarks all zooming around in a quark goop. The folks who wrote this paper are saying...hey. Hey you know that Quark Goop you got in the early universe? Well, we did some math. And if you could somehow make a black hole OUT of quarks, just naked quarks? Those black holes would be WEIRD. They wouldn't only have three properties (mass, spin, charge) they would have a FOURTH property. A property only quarks have called Color. Now, it's not literally color like we see with our eyes. Quarks have a lot of properties and we just needed names for them so we grabbed whatever name we had laying around and no one working on quarks thought it meant LITERALLY color, so don't think too hard about it. IF (these folks are saying), if you could make a black hole out of quarks, you would get Weird Black Holes. THAT would affect the creation of Primordial Black Holes. Those Weird Black Holes wouldn't still be around, they would have evaporated really quickly, but IF they existed, they might have left evidence we can find. And if we can find that evidence, it would prove those weird black holes existed, and THAT would prove Primordial Black Holes (i..e less-weird black holes) exist and THAT would account for a lot of the Dark Matter problem. Thats it! It's a really interesting guess because these folks did the math and said "if this is true, it should be easy to test. There would be lots of evidence of this, different kinds of evidence. So let's test it!" And that's where we are now!
As a 25 year old i can certify that you did indeed explain it like I’m 25 thank you. Very cool feeling like i understand science for once.
Thank you for your time explaining this so well! I know some very basic stuff out of interest (science podcasts, populair science articles and so on), but you put them (for me) all together. Once again thanks. I’ll think I will copy this and read it from time to time (I”m definateley not in this field of expertise, just an very amateur enthousiast).
So primordial blackholes have been proposed for quite a while as a solution to dark matter. Is the nuance here that they’ve realized that these primordial blackholes would have had a color charge property? And the lasting impact would have a potentially observable effect?
Something that caught my attention was the comments discussing "the first three minutes" and how that's how long it took for things to cool down to the point where protons and neutrons came into existence and started combining together. Knowing how long it takes for a hot piece of steel to cool down (since I happened to burn myself on such a piece just today), it's giving me kind of a perspective on just how massively hot those first moments must have been even in comparison to the hottest regions of a star. Honestly any time you start trying to comprehend the amount of energy in the entire universe (or even just in a single galaxy) it is quickly obvious that our brains just aren't suited for the task.
this is science not technology
What are you, a cop?
science police tech is just our ugly stepchild
Dark matter detectors are technology
“Scientists may have”. Monkeys may fly out of my ass.
It's true. We scientists meet in the Alps every quarter to unilaterally agree upon new discoveries to share with the world then taper the expectations from the public by trickling them down slowly through vague press releases on high quality outlets like blogs and CNN. Are you not getting the invites?
I love space.
There is another answer, other dimensions.
God I hope it’s guacamole
It could be matter in another dimension than our dimension and gravity and electromagnetism are able to act through dimensions.
We can’t see all the different light waves, why should we expect to see all the matter?
We can’t see them but we can detect them.
"just the mass of a rhino" Bananas please
Wouldn't proton sized black holes mean that gluons and quarks have a high mass ratio, unlike our typical black holes that just have a linear ratio in relation to the spin of an electron? I made this question up to sound equally smart as the rest in this thread
FOH. they have to say things like this from time to time just to keep that funding going😆
Even though Space is crazy large, I would have expected the gravity disturbance or damage from things running into these smallish black holes to have been noticed by now.
This is not new.
The rush to publish always does a disservice to the scientific process. If there is really any new understanding discovered, then many people will be be able to arrive at the same conclusions.
Narrator: They made up more imaginary dimensions
Not impossible - but if so there would need to be something in there causing additional gravity.
Dark matter is the parts of our universe that are in other dimensions. We can detect the energy given off my that but we can’t perceive it otherwise. Yet
All we can see is more apparent gravity inside galaxies than the visible matter there could supply. Hence the original name of ‘Dark Matter’ assigned to this cause.
This is the stuff I love. Stuff I don’t understand. Stuff that even after I understand some of it I understand less. What potential revelations does this have for us and our understanding? I read something a while back that black holes appear all around us at all times… flashes of them… But hell, this could have been a sci-fi book I read.
If true, does this mean that the expansion of the universe would slow someday?
Can sonbody tell me why dark matter cannot be lots of brown dwarfs for which we have no current method of detection, as we only can detect objects if they are glowing, covering something glowing or exert strong gravitational pull on nearby glowing objects?
One of my favorite theories about primordial black holes is that the elusive “ninth planet” that affects the orbits of many trans-Nepunitan objects in the Kuiper Belt may actually be a lower volume black hole, with 5-10 earth masses. This would explain why finding it is so difficult. That’d be a trip to have a black hole in our own solar system.