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Can we make a black hole? And if we could, what could we do with it?
- dmje 4y ago
- zw123456 4y agoI dunno what you could do with it but the black hole laser bit blew my mind https://arxiv.org/abs/1409.6550 https://arxiv.org/abs/1409.6550
- deleted 4y ago[deleted]
- bell-cot 4y agoExtremely Understated summary answer (to the first question), from the article: > So some engineering challenges that remain to be solved.
- sylware 4y ago"indeed, we need to fit half the universe in a grain of sand, more funding is required to overcome this challenge". ...
- samstave 4y agoTwitter takeover funding has entered the chat.
- catmanjan 4y agoHow many story points would you allocate for this one?
- toxicFork 4y ago12.1
- adbachman 4y agoAnything over 8 is probably an epic.
- deforciant 4y agoCould you please split it into multiple tickets that we no bigger than 3 points
- sharkweek 4y ago“If you wish to make an apple pie from scratch, you must first invent the universe”
- Victerius 4y ago> Roger Penrose already pointed out in the early 1970s that it’s possible to extract energy from a big, spinning black hole by throwing an object just past it. This slows down the black hole by a tiny bit, but speeds up the object you’ve thrown Black hole railguns/artillery? Or, in the name of safety, mobile satellites in low earth orbit armed with hard tungsten rods, accelerated by temporarily generated black holes to relativistic velocities for prompt global strikes on time sensitive targets. Could make for a good movie.
- flatiron 4y agosmall black holes are there for nanoseconds, im not really sure you could find a good method to "shoot" them the whole "you can shoot somin near a black hole and speed it wayyyyy up" reminded me of the three body problem. some advanced species just tossing crap at black holes and blowing up stars
- Jenk 4y agosurely the law of conservation applies, in that it would be more efficient to take the energy used to generate the black hole and apply it directly to launching the projectile instead?
- Out_of_Characte 4y agoWell, its essentially a black hole railgun. Exept a railgun uses the magnetic force instead of gravity. and black holes are 'theoretically' really efficient at converting mass to energy.
- XorNot 4y agoIt would, although the utility of using a black hole has a universal mass-energy converter would be substantial. Take any matter you want, toss it in to be crushed and then extract it back out as kinetic energy you can use to make electrical power.
- samstave 4y agoHow would one "rods from god" on a timely manner.. You cannot harvest the energy given to you by a blackhole... unless the impacts of tungsten objects yield harvestable energy.
- ajuc 4y agoSome other uses of black holes: - space propulsion https://www.youtube.com/watch?v=oAocMzxPjjo https://www.youtube.com/watch?v=oAocMzxPjjo - colonization and energy source https://www.youtube.com/watch?v=Qam5BkXIEhQ https://www.youtube.com/watch?v=Qam5BkXIEhQ - weapons https://www.youtube.com/watch?v=zTMxO1nJaA4 https://www.youtube.com/watch?v=zTMxO1nJaA4 I highly recommend the whole channel.
- jacquesc 4y agoAlso a great (short) one by Kurtzgesagt https://youtu.be/ulCdoCfw-bY https://youtu.be/ulCdoCfw-bY
- hammock 4y agoWe could throw garbage or nuclear waste into it
- restalis 4y agoFrom the article: "if the black hole’s temperature is high, the radiation is composed of all elementary particles, photons, electrons, quarks, and so on. It’s really unhealthy. And a small black hole converts energy into a lot of those particles very quickly. This means a small black hole is black basically a bomb." The nuclear waste thrown into it may be much cleaner than the stuff it will throw back out.
- sliken 4y agoTrue, but that's tunable, the bigger it is the less comes out.
- ben_w 4y agoThanks for reminding me I needed to blog about why I think Hawking radiation drives aren’t really as good as they look: https://kitsunesoftware.wordpress.com/2022/05/14/no-a-black-hole-cant-be-used-as-a-rocket/ https://kitsunesoftware.wordpress.com/2022/05/14/no-a-black-... (I agree that Isaac Arthur’s channel is good).
- CryptoPunk 4y ago
- _jal 4y ago"Io, corner pocket."
- h2odragon 4y agothere's a potential video game there. planet pool. dropping things into the sun would be a "scratch"?
- bjt2n3904 4y agoOne question I had, prompted by a fever dream in which a black hole spawned in my house... If a black hole were to come into sustained existence, assume the smallest one. How long could we stand near it before being unable to escape? And how far is that distance?
- helldritch 4y agoThe equation for escape velocity is: v = √(2GM/R) R = distance (radius, really) M = Mass of the body G = Universal gravitation constant We can modify this equation to find for the distance at which you can escape: r = 2GM/v^2 The answer is largely: it depends on how fast you can go, at the speed of light you can escape from further away, since the pull will increase the closer your are to the "event horizon". I'm in a car right now (as a passenger ofc) doing this from my phone so not in a situation where I can put together a model, but you should be able to plug in some numbers and estimate a result, just make sure you convert to SI units so you don't accidentally end up 3 orders of magnitude off. A black hole with the mass of the earth would have a radius of about 2cm, so things less massive than a planet start to get very small, very fast, and you end up fighting quantum effects which become less intuitive.
- DJBunnies 4y agoThat's called the event horizon, which is proportional to its mass.
- justsomeshmuck 4y agoIt's theorized that there is a grapefruit-sized black hole orbiting our sun in the outer reaches of our solar system with a mass of 5 to 10 earths. A black hole spontaneously appearing in your home small enough to not rip apart the entire planet immediately would probably be too small to notice without some sort of detection equipment.
- codethief 4y ago> It's theorized that there is a grapefruit-sized black hole orbiting our sun in the outer reaches of our solar system with a mass of 5 to 10 earths. Source: https://arxiv.org/abs/2004.14192 https://arxiv.org/abs/2004.14192 (There was also a pretty good discussion about it here on HN.) > would probably be too small to notice without some sort of detection equipment. What makes you think that?
- PaulHoule 4y agoIf a ‘Type III’ civilization is meaningful it could be one that uses a quasar the way we use a star.
- Aeronwen 4y agoThey should harness it's energy instead.
- Mizza 4y agoWhen I was a kid I was really afraid that particle colliders would create a black hole that would sink to the center of the earth and eventually eat us all, so I find this article quite soothing.
- sohkamyung 4y agoCosmic rays with higher energies than that from human particle accelerators hit the Earth on a regular basis. If Black holes could have been formed by them, we wouldn't be around to ask, so actually not much to worry about particle accelerators generating Black holes. > https://www.pbs.org/wgbh/nova/article/the-astronomical-particle-colliders-that-put-our-own-to-shame/ https://www.pbs.org/wgbh/nova/article/the-astronomical-parti...
- tzs 4y agoYou can't infer from our failure to not exist that cosmic rays hitting Earth never create black holes. All you can infer is that any such black holes aren't dangerous. That still is sufficient to support your overall thesis that since cosmic ray black holes are not a problem we don't have to worry about black holes from colliders so your overall point stands. Black holes formed by cosmic rays hitting Earth would not be dangerous because they would be very very small. Most likely they would very quickly decay via Hawking radiation, but even if they did not decay for some reason they would be so small that very little would actually fall into them. Small black holes created in the early universe, big enough to not noticeably decay in the billions of years since and so much bigger than those cosmic rays hitting Earth might create, are actually taken seriously as one of the candidates for dark matter. Even those, which would be much larger than anything cosmic rays or colliders might make, would be sufficiently hard for things to actually fall into that they could pass right through you without you noticing.
- deleted 4y ago[deleted]
- xwdv 4y agoIt’d be cool if we made a black hole type bullet that would suck someone or something in completely on impact and dissolve. Not sure if feasible though.
- InCityDreams 4y agoSome parts of heyjackass.com immediately sprang to mind.
- h2odragon 4y agoVastly increasing the target's density would do for that; no need to go past that into full singularity. cf "Neutronium Alchemist" in Peter F Hamilton stories. It'll never be as simple or satisfying as the old school hammer.
- pas 4y agoyes, but no :) so as the blackhole gets smaller the more energy it radiates, eventually basically blowing up. so simply put a small BH in a magnetic trap next to someone. but if you shoot it it'll go too fast to stay put. though it might be possible to release a small one next to someone slowly. small means ~ 1 million kg, which evaporates in 84 seconds, though it will emit so much energy that... well it will turn a city into plasma almost instantly https://www.omnicalculator.com/physics/black-hole-temperature https://www.omnicalculator.com/physics/black-hole-temperatur... basically the problem is that either general relativity and Hawking are correct, which mean that there is simply no way to have a small (compared to human mass, so like a big bomb, eg a few metric tons) black hole that doesn't violently want to turn back into a non-blackhole, or if it's possible then our theories are incorrect and all bets are off :)
- sliken 4y agoSeems just like a grenade. You time the throw so your target gets destroyed. Incredibly efficient, since unlike nuclear or fusion nukes 100% of the matter gets turned into energy.
- shusaku 4y agoOutlaw Star had it!
- gentleman11 4y ago> what could we do with it Putin merely has access to nuclear weapons. I suppose the “I win or the earth gets it” is the same whether we’re talking nukes or a black hole
- amelius 4y agoWe could put a black hole over Russia, so that any ballistic missiles they launch get sucked up in it.
- mrkramer 4y agoMaybe we could make Black Hole Computers[0]? [0] https://cse.buffalo.edu/~rapaport/111F04/lloyd-ng-sciam-04.pdf https://cse.buffalo.edu/~rapaport/111F04/lloyd-ng-sciam-04.p...
- deleted 4y ago[deleted]
- sidlls 4y agoOne of my favorite science fiction stories, "The Krone Experiment", has this question as a central plot element. https://www.goodreads.com/book/show/16032842-the-krone-experiment https://www.goodreads.com/book/show/16032842-the-krone-exper...
- nyc111 4y ago> So, if you hold the mass fixed and compress an object into a smaller and smaller radius, then the gravitational pull gets stronger. Eventually, it becomes so strong that not even light can escape. You’ve made a black hole. In Newtonian doctrine, a spherical object, like earth, attracts -as if- all its mass is concentrated at its center. So, if her reasoning is correct, the earth must already be a black hole, because all its mass is supposed to be concentrated at its center.
- al2o3cr 4y agoattracts -as if- all its mass is concentrated at its center That's only 100% true for a radius _outside_ of the object. At a radius _inside_ the object, only the mass closer to the origin counts so the "effective" mass of the object drops smoothly to zero.
- sliken 4y agoActually it's something like 2 radius, unlike the earth there's no stable orbits under 1.5 or 2 radii (I forget which). Outside of 2 radii there's no differences.
- jfengel 4y agoNo, because that approximation only works when you're outside the object. Once you're inside the object, any shell of mass outside your distance from the center cancels itself out (produces zero net force). So the escape velocity from earth at its surface is well below the speed of light. And below the surface, gravity is even less. Only a black hole packs enough mass into a small enough place to get the escape velocity above the speed of light.
- _Microft 4y agoIf GP wants to read about this, the name is actually "shell theorem": https://en.wikipedia.org/wiki/Shell_theorem https://en.wikipedia.org/wiki/Shell_theorem
- marcosdumay 4y ago
- gradschool 4y agoI admit I know next to nothing about this stuff, but something doesn't add up. If everything has a Schwarzchild radius determined by its mass, then should we conclude that particles like electrons and protons also have a (very small) Schwarzchild radius? If the smaller it is, the sooner it explodes, then shouldn't atomic particles have all finished exploding a long time ago? When they explode, what do they eject, if not more subatomic particles like themselves? Alternatively, is the explanation that atomic particles are extended bodies whose sizes exceed their Schwarzchild radii instead being of point masses? If so, then what kind of stuff fills the interior of an electron? I don't have any answers but I have a feeling we're on shaky ground when we start trying to extrapolate general relativity concepts to atomic scales. edit: typo
- vbezhenar 4y agoAccording to my calculations, schwarzschild radius of electron is 1.4e-59 m, and electron radius is 2.82e-15 m, so electron is huge and electron density (if such thing exists) is not enough to form black hole.
- platz 4y agoyour "electron radius" is the "classical electron radius" which is a ficticious radius one uses i lf disires. in modern theory electrons have no radius.
- codethief 4y ago> If everything has a Schwarzchild radius determined by its mass, then should we conclude that particles like electrons and protons also have a (very small) Schwarzchild radius? https://en.m.wikipedia.org/wiki/Black_hole_electron https://en.m.wikipedia.org/wiki/Black_hole_electron > If the smaller it is, the sooner it explodes, then shouldn't atomic particles have all finished exploding a long time ago? See my other comment here: https://news.ycombinator.com/item?id=31378092 https://news.ycombinator.com/item?id=31378092 > I have a feeling we're on shaky ground when we start trying to extrapolate general relativity concepts to atomic scales. Correct. We know nothing about how to marry General Relativity with atomic-scale physics (quantum mechanics). That's why everyone and their dog are looking for a theory of quantum gravity.
- daniel-thompson 4y agoThis is the kind of question that makes me believe in the Great Filter¹. ¹https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter
- codethief 4y agoCame here to post this but couldn't remember the name "Great filter", thank you. :)
- BiteCode_dev 4y agoThis is the kind if questions which justifies the need for humanity to colonize multiple planets if it doesn't want to go extinct.
- morekozhambu 4y ago
- deleted 4y ago[deleted]
- ck2 4y agoThe horrible but obviously accurate answer is it would be weaponized. This is what I worry about with fusion, it's not going to be used for free power for the world, it's going to be used to power war-machines.
- XorNot 4y agoWhy though? The only value of a black hole you can build would be as a doomsday weapon: do what we want or we end the world. Except...that's been the case since the Cold War with regular nuclear weapons. As for fusion: you need to do more research. We've had fusion bombs since 1952. Practical fusion power for electrical generation is what we don't have since the constraints are very different.
- ravi-delia 4y agoIt's handier interstellar if you can find a way to accelerate it at any real velocity I guess. At that point I can't imagine it's easier than just chucking a projectile at some absurd fraction of c
- rolph 4y agoyou are suggesting singularity munitions, as others have before. the process is not known but the desired product is- arbitrarily create an unstable singularity that converts surroundings out to a radius into energetic content leading to explosive "jetting" and gravity wave propagation until spacetime re-normalizes.
- donutshop 4y agoWould be neat to suck up all the garbage
- sliken 4y agoSure, but the weight would still be there, and whatever containment you had would be more stressed, till it fell into the local gravity well, which near earth would be bad.
- xg15 4y ago> So, if you hold the mass fixed and compress an object into a smaller and smaller radius, then the gravitational pull gets stronger. I find this bit interesting because I'm pretty sure I've read the exact opposite before. My previous understanding was that the gravitational pull is only determined mass - but a black hole can put an almost arbitrary amount of matter into the same space, therefore the gravitational pull is factually much stronger than for any "ordinary" object of the same radius. However she is saying the compression itself is already increasing the pull. So as an example, suppose our sun got replaced by a black hole of identical mass (but much smaller radius). Would this cause orbits of the planets to shrink (increased gravitational pull) or stay the same (identical gravitational pull)?
- lilgreenland 4y agoMass and energy are same thing. They effect gravitational pull the same. If you compressed the Earth the energy it takes to compress the Earth would increase the mass-energy of the Earth, and this would change the orbits of planets.
- deleted 4y ago[deleted]
- zmgsabst 4y ago> If you remember Newton’s gravitational law, then, sure, a higher mass means a higher gravitational pull. But a smaller radius also means a higher gravitational pull. So, if you hold the mass fixed and compress an object into a smaller and smaller radius, then the gravitational pull gets stronger. Eventually, it becomes so strong that not even light can escape. You’ve made a black hole. I think this is discussing the gravity on itself — or the peak gravitational pull, for nearby objects. Compressing the Earth wouldn’t make far away objects experience it differently, but compressing Earth would increase the peak pull nearby — to the point of creating a black hole. Much more gravitational pull than anywhere on Earth experiences now. But that radius would be far, far inside of where the surface currently is. Density increases nearby gravity by focusing mass.
- xen0 4y agoGravitationally, nothing would change if the sun was replaced by a black hole of the same mass, at least for objects above the surface of the current sun. But being 1 kilometer above the event horizon of that black hole would be very different to being 1 km above the surface of the sun. As the radius of a object shrinks (but with mass held constant), the _surface_ gravity increases. Remember that the pull of gravity decreases with the square of the distance away from the object. With a smaller object, you can get a lot 'closer' to all that mass, so gravity is stronger at its surface.
- DerekBickerton 4y ago♩ ♪ ♫ ♬ Black hole sun, won't you come And wash away the rain? Black hole sun, won't you come? Won't you come? Won't you come? ♩ ♪ ♫ ♬ https://www.youtube.com/watch?v=efc7njKAfgo https://www.youtube.com/watch?v=efc7njKAfgo
- andrekandre 4y ago> Slight problem with this is that you can’t touch black holes, so there’s nothing to hold them with. A black hole isn’t really anything, it’s just strongly curved space. They can be electrically charged but since they radiate they’ll shed their electric charge quickly, and then they are neutral again and electric fields won’t hold them. So some engineering challenges that remain to be solved. im not even sure how to begin there... probably the only wait contain a black hole would be... warping space-time negatively? like kind of warp bubble?
- XorNot 4y agoIt's just a gravitationally attractive body: it moves towards the net gravitational force acting on it. So you could control it by trucking sufficiently large masses closer or farther away within a suitably large containment area, provided it wasn't too massive. Easiest thing to do though would be to build it in orbit.
- GlenTheMachine 4y agoGood way to clean up space junk
- swayvil 4y agoUnlike the trash bucket in Linux. 1 time out of 20 you go back and restore that thing you trashed. And damn glad you are to have that power. Black holes, otoh, are forever.
- platz 4y agothey are not forever.
- swayvil 4y ago
- hammyhavoc 4y ago
- swayvil 4y agoIf we had "reverse centrifugal force" you could create a black hole by "spinning" the thing really fast.
- tsukurimashou 4y agoJust spin it the other way around :^)
- techdragon 4y agoSurprised no one has mentioned the Kugelblitz yet, so I’ll drop this fun hit of exotic theoretical engineering here. https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics) https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics)
- cletus 4y agoBlack holes created from energy are called Kugelblitz black holes [1]. The article correctly points out the difficulty of doing so with traditional lasers. But if we can ever figure out a way to reflect (and thus lase) gamma rays (or some other much higher energy radiation) this then becomes possible. Of course we don't even have a plausible theory on how we might construct "grasers" [2]. [1]: https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics) https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics) [2]: https://en.wikipedia.org/wiki/Gamma-ray_laser https://en.wikipedia.org/wiki/Gamma-ray_laser
- thfuran 4y agoAre free electron lasers fundamentally incapable of operating up into gamma? Maybe we just need to wiggle harder.
- doodlebugging 4y agoI remember back in the day when cartoons had black holes you pull out of a pocket and throw down to use either as a portal to a different part of the cartoon or as a way to send your antagonists somewhere else. I think that's where we should start in looking at potential use cases for personal, instant black holes. I'm not young any more so I would volunteer to help in development and testing of any portals as long as I get good Cajun coffee and a smoked brisket sandwich in the lunchbox with a blood orange and a slice of Mom's apple pie.
- imiric 4y agoNow you're thinking with portals.
- a1369209993 4y agoWhile that is a hole, and is black, it's a totally different and unrelated kind of black hole from what TFA is talking about (and is more commonly called a "portable hole", after the version in Dungeons and Dragons).
- doodlebugging 4y agoI understand that there may be other things to consider here. But, if given the opportunity to dink around with the physics and end up with an instant pocket portal that can do the cool cartoony stuff I am willing to give it a whirl. I can see where it could be used in hot climates to help avoid energy waste. Buildings could be built with no doors and using UV reflecting glass for windows and people would enter and exit with their own personal pocket portals. Had enough for one day and feel like a cold brew? Flip that pocket portal like a disc golf disc and when it sticks to the wall just jump thru it to the street. It closes up behind you allowing for the absolute lowest conditioned air loss situation. No more door and threshold gaskets to replace, ever. Just keep your portal tuned to the right energy level and make sure that you never let it work like your money, burning a hole in your pocket.
- a1369209993 4y ago
- llIIllIIllIIl 4y agoSend trash in it.
- amelius 4y agoFirst two sentences of the article: > Wouldn’t it be cool to have a little black hole in your office? You know, maybe as a trash bin.
- devoutsalsa 4y agoNot from the video… What blew my mind was to learn that a black hole get bigger when it absorbs light. Light from a campfire you had as a kid could be feeding a black hole right now.
- beeforpork 4y agoWell, yeah, it is weird at first. But once you think about it, it is not unintuitive: if the light was just gone, that would be wrong, too, right? Also, energy == mass, so of course, it is equivalent to throw mass into a black hole or energy. The longer I think about it, the more it is mass that is the weird thing. What is mass? Something like frozen energy...
- abhaynayar 4y ago> Light from a campfire you had as a kid could be feeding a black hole right now. I don't think we have a close enough black hole for this to be true for anyone reading this right now.
- sliken 4y agoMaybe, there's a theory that the 9th planet is a black hole, and that's why it's very hard to detect outside of the gravitational effects. Amusingly there's a diagram in the paper that's a 1:1 diagram (life size) in the paper. Would be crazy if true, we could verify all kinds of things by tinkering with a live black hole.
- samatman 4y agoThe Earth gets bigger as well, and by the same mass per photon, when it absorbs light. It loses this mass through radiation, but then, so does a black hole. That's fancy Proper Noun Hawking Radiation, but radiation it remains. Not trying to be a downer, I find the fact that a photon doesn't /have/ mass but still /is/ mass endlessly fascinating.
- juanani 4y ago
- _8j50 4y agoI think this discussion is too focused towards stable blackholes. How useful can unstable (even nanosecs) blacholes be?
- dioramayuanito 4y agoAwesome