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The strange fate of a person falling into a black hole
- guard-of-terra 11y agoYou can only get inside black hole after time ends. That's because universe-time stops at the horizon. The moment you fall in, Anne is dead eternally long ago. Also, you are incinerated by a billion years of starlight per your second, including energetic particles I guess. You will observe the end of universe and death of everything in it before diving.
- thomasahle 11y agoWell, it has to be slightly more complicated than that. After all you are going to be emitted as hawking radiation a lot earlier than the end of the universe.
- deleted 11y ago[deleted]
- guard-of-terra 11y agoLarge black holes have life expectancy so much larger than universe age that it's not even funny. They're not going anywhere AFAIK. No, you will stay there and watch. "The power in the Hawking radiation from a solar mass black hole turns out to be a minuscule 9 × 10−29 watts. It is indeed an extremely good approximation to call such an object 'black'."
- tfgg 11y agoLarger than the current life of the universe, not necessarily longer than the end of the universe, though that really depends on your model of how it'll all end. Some do involve black holes gradually boiling away to radiation being the last things being left.
- guard-of-terra 11y agoMaybe there would be an eternity of black holes boiling / protons decaying. I doubt that since something ought to lose stability in the long run.
- logfromblammo 11y agoIf spacetime continues to accelerate its expansion, a black hole at the future end of time might be like suddenly dropping the air pressure over a boiling pot of water--or maybe more like popping a blackhead pimple by stretching the skin on either side of it. I am not a theoretical physicist, though, so whenever I think too hard about how that would actually work, I give myself a headache and need a good lie-down in a very dark room.
- tvmalsv 11y agoIf that were the case, wouldn't that mean that the moment a black hole is formed, it would never become any larger? How have super-massive black holes formed in less than 14 billion years?
- guard-of-terra 11y agoThis is a very interesting question and I'm unaware of a definite answer.
- ars 11y agoThe answer is both simple and controversial: They have not. Black holes do not exist because they take an infinite amount of time to form. See the thread elsewhere on this page.
- oldmanjay 11y agoYou're making some awfully assertive statements for not having proved your case. Dismissal of all answers as "hand-wavy" does not actually make your non-argument more compelling.
- jdmichal 11y agoThe concept is known as "eternally collapsing objects", and has survived peer review just as much as any other concept discussed here. http://en.wikipedia.org/wiki/Magnetospheric_eternally_collapsing_object http://en.wikipedia.org/wiki/Magnetospheric_eternally_collap... This is actually something that is verifiable, given time, since traditional black holes may not sustain their own magnetic field, but MECOs can.
- repsilat 11y ago> The moment you fall in, Anne is dead eternally long ago. Nonsense. By this logic, if you cross the event horizon feet-first, your head will have died of old age before it gets inside!
- guard-of-terra 11y agoIt is not so, as the relative time difference between your feet and head is very small (for large black holes). There is no barrier in place of event horizon, but from the POV of external observer it takes infinite time for you to dive.
- repsilat 11y ago> the relative time difference between your feet and head is very small If there's nothing significant going on between your head and your feet, there's nothing significant between your head and an "external observer" two metres above your head. Say Anne is falling in behind you, and she either decides to "back out at the last minute" or just keep falling with you. As you fall, time is passing more or less the same for the both of you, so we can just go by your clock: You cross the event horizon at t=0, she makes her decision at t=1, and she either crosses at t=2 or doesn't cross at all. Now, if Anne "backs out", her clock does diverge sharply from yours as she stops her fall and accelerates away from the event horizon, but this clock divergence happens after you've crossed the event horizon, not as you cross it or before.
- guard-of-terra 11y ago"there's nothing significant between your head and an "external observer" two metres above your head." Of course, but when we talk about "external observer" far from the black hole, difference appears.
- deleted 11y ago[deleted]
- joelrunyon 11y agoArticles like these are great reminders to question everything you think you know.
- guard-of-terra 11y agoI find this "new age" mentality annoying. Yes there are things we don't know, but we should try to come up with precise questions, not to ponder about the meaning of black holes in philosophical way. Start small, figure things out.
- joelrunyon 11y agoIt's not really a new age mentality at all (I wouldn't classify myself as that at all). If anything, it's a strictly scientific mindset. It's more of a reminder to think that even when we start to understand some incredible things, there's still a TON out there we DON'T know. I think that's where the cool revelations come in, when you start to understand how much out there you don't know much about. That's where the wonder starts (which tends to bring up some of those specific questions).
- deleted 11y ago[deleted]
- guard-of-terra 11y agoIf you read comments to this article, it's hard to not notice that most commenters discuss angels dancing on the head of a pin.
- golgappi 11y agoWhat's wrong with imagination, hypothesis and a simple analogy that can reach out to the masses? One might argue that your approach to science as only a set of facts based on formula is boring at best. One needs to ponder the meaning behind the formula and results. Yes, we got a number, but what is the implication of it? After all, doesn't science exist to satisfy our curiosity about the world in the first place?
- racheldav 11y agoLOL, Is it great news on hackernews ?
- deleted 11y ago[deleted]
- repsilat 11y ago>there is no paradox, because no one person ever sees your clone. Anne only sees one copy of you. You only see one copy of you. You and Anne can never compare notes. Can't you? Why can't Anne "gather up your ashes" and send them into the black hole, where you can inspect them? Shouldn't that go against the "no cloning theorem"?
- kagamine 11y agoGiven the initial split in realities, Anne would create a new parallel universe when she placed your ashes in the black hole, one in which they exist outside the black hole and in a parallel universe where they exist inside the black hole, but this is not the same parallel universe you are experiencing, but a parallel parallel universe. Essentially, 2 instances of the black hole.
- caf 11y agoI think this is begging the question.
- repsilat 11y agoThe theory very explicitly does not posit a "split in realities" or "parallel universes" or anything of the sort. It says there is quantum information both inside the black hole and outside it, and this is ok because they're supposedly causally disconnected from one another.
- kagamine 11y ago> The instant you entered the black hole, reality would split in two. From the 3rd paragraph. However, yes the alternate universe comes into existence when you reach the singularity. Still, if you can exist both inside and outside, then your ashes can exist in both places alongside living you without causing a paradox because you simply will not exist in the same space as you ashes that will arrive very much later anyway as time slows at the edge of the black hole. You are more likely, having read the article, to have a post-life crises knowing that outside the black hole you are dead.
- Varkiil 11y ago"In a big enough black hole, you could live out the rest of your life pretty normally" Free falling in your ship and suit waiting for you to be crushed to death... pretty normally
- antimagic 11y agoIt depends on what you mean by "inside" a black hole. If this means "inside the event horizon", well, if the black hole is big enough, you can put yourself in orbit around it relatively easily, you'll just never be able to achieve escape velocity. If you take the Earth for example, a geosync orbit has a velocity of 3.07km/s, whereas escape velocity is 11km/s
- dvdkhlng 11y agoThere aren't any stable orbits within the event horizon of a black hole (due to General Relativity): https://en.wikipedia.org/wiki/Schwarzschild_metric#Orbital_motion https://en.wikipedia.org/wiki/Schwarzschild_metric#Orbital_m...
- antimagic 11y agoNot so, only one of the two solutions is unstable: https://en.wikipedia.org/wiki/Schwarzschild_geodesics#Circular_orbits_and_their_stability https://en.wikipedia.org/wiki/Schwarzschild_geodesics#Circul... Also, this applies only to circular orbits, and does not indicate that a powered ship could not maintain orbit.
- repsilat 11y agoThose orbits are all outside the event horizon. Inside it, all you can hope to do is fall inward as slowly as possible.
- dvdkhlng 11y agoBTW most of what I know about black hole physics is from Greg Egan's novel "Incandescence". Which covers quite a lot of science for a work of fiction (and overall extremely inspiring). http://gregegan.customer.netspace.net.au/INCANDESCENCE/Incandescence.html http://gregegan.customer.netspace.net.au/INCANDESCENCE/Incan...
- dvdkhlng 11y agoSomewhat related: there is a short story by Greg Egan, "The Planck Dive", describing a voyage (without return) into a black hole, in a scientifically not too absurd way. You can read it online: http://gregegan.customer.netspace.net.au/PLANCK/Complete/Planck.html http://gregegan.customer.netspace.net.au/PLANCK/Complete/Pla...
- jamesdelaneyie 11y agoHave yet to read this but huh – manually responsive web design!
- aesthetics1 11y agoThat's actually really interesting. Imagine having a feature like this built into browsers for dealing with long articles and text. Yes, we have 'zoom' but that typically breaks things at a certain point. Easily swapping the background and even the left/right bias of the text is a pretty neat tool to include, even though it isn't that intuitive on the site.
- alkonaut 11y agoWhat do we know about the nature of entanglement? Does it make sense to talk about entanglement between regions inside and outside of an event horizon? Couldn't it be the case that entanglement too breaks down somehow at the event horizon?
- BenderV 11y ago"That's the thing about black holes. They're not just annoying obstacles for space travellers. They're also theoretical laboratories that take the subtlest quirks in the laws of physics, then amplify them to such proportions that they can't be ignored." I also use this strategy to think about philosophy and science. People often think that because they are extremes, they are not relevant. However, they are as relevant! And they force us to think outside our natural instinct.
- DigitalSea 11y agoI recently saw the movie Interstellar starring Matthew McConaughey. It answers the question of what happens if you fall into a blackhole and it involves a bookcase, I don't want to spoil it for those who haven't seen it. Edit: Seems the people downvoting me are a bit sensitive and don't have a sense of humour. Sorry to anyone who was somehow offended.
- Avalaxy 11y agoVery interesting if you want some more background is the book 'the science of Interstellar'.
- ekianjo 11y agointerstellar was more a pile of nonsense than Science.
- Avalaxy 11y agoHave you read the book? That's solid science and contains good explanations on why things were done the way they were done.
- loqi 11y agoI haven't read the book, but from what I gather[1], the explanations were not all good. Getting to and from Miller's world should have required absurd amounts of energy. But as extreme luck would have it, there were "intermediate-mass black holes" positioned ever-so-conveniently to make those trips possible (along with some other stuff). Cherry-picking the physics you like and papering over the rest with a series of extremely implausible coincidences isn't good science or good storytelling. [1]: http://www.scottaaronson.com/blog/?p=2040 http://www.scottaaronson.com/blog/?p=2040
- jessaustin 11y agoThis is not an insightful response. Of the people I know who watched the movie, those who objected the most to the science were those with little scientific training. (Similar to a relative of mine who is certain that we will "never" have self-driving cars...) If you are knowledgeable, and have specific objections, those might be more insightful.
- jayman 11y agoI think we are in a black hole already. We just don't know it yet. :D
- gpvos 11y agoThere is actually a recent theory that says this is the case (in a way): http://scitechdaily.com/universe-may-emerged-black-hole-higher-dimensional-universe/ http://scitechdaily.com/universe-may-emerged-black-hole-high... .
- jetskindo 11y agoWhat a coincidence that I finish watching interstellar and the minute I check my phone this is the number one post. Maybe I made that happen.
- strictnein 11y agoSurprisingly, they only snuck in one Interstellar reference, and it was pretty vague: > "Alright, a l r i g h t, a l r i…" https://www.youtube.com/watch?v=FiTaK3Fyj0k https://www.youtube.com/watch?v=FiTaK3Fyj0k
- juliangregorian 11y agoHa, and here I thought maybe it was a reference to "Hey Ya"
- logfromblammo 11y agoBy my count, there are three. > What happens here, no one knows. Another universe? Oblivion? The back of a bookcase? It's a mystery. The back of a bookcase. That might also be a reference. > Let's start by asking your space companion — we'll call her Anne — who watches in horror as you plunge toward the black hole, while she remains safely outside. Perhaps the outside observer's last name is Hathaway?
- JonnieCache 11y agoI once saw a susskind lecture about the firewall problem where he explained that to check if someone falling into a black hole was incinerated, you'd have to fire so much energy at them, you'd end up incinerating them. Physics is weird. And, apparently, kinda passive aggressive. BONUS EDIT: here's a Greg Egan short story about transhumans diving into a black hole and trying to do physics on the way down: http://gregegan.customer.netspace.net.au/PLANCK/Complete/Planck.html http://gregegan.customer.netspace.net.au/PLANCK/Complete/Pla... also here's his page explaining the physics in the story: http://gregegan.customer.netspace.net.au/PLANCK/Planck.html#CONTENTS http://gregegan.customer.netspace.net.au/PLANCK/Planck.html#...
- pathdependent 11y agoThank you for this morning's diversion.
- AceJohnny2 11y agoIs that the story in which there's a discussion about whether space-time is continous or discreet, the former case allowing infinite computation as you dive into, the latter not?
- JonnieCache 11y agoI think I remember that coming up, amongst many other things.
- ankurdhama 11y agoMost of theoretical science and science fiction is complete bullshit. They use some analogy and run with their wild imagination to create anything utterly non nonsensical. The space time fabric etc is just an analogy to avoid people from the real mathematical equations of relatively and what people did with it created whole shit load of theoretical science around that analogy.
- rnhmjoj 11y agoRelevant xkcd: https://xkcd.com/895/ https://xkcd.com/895/
- PuffinBlue 11y agoI always assumed the differing 'views' of what would happen crossing into a black hole was a product of the interplay of the equivalence principle and 'relativity of simultaneity' that Special/General relativity already accounts for. I had thought that upon reaching the event horizon the outside observer sees time 'stand still' because no light from your continued motion the other side of the event horizon can reach them, effectively freezing the observers view. Or thought of another way, the curvature of spacetime at the event horizon reaches the equivalent velocity of c due to the extreme warping of spacetime, so light can't escape and 'time' stops for the observers view of the freefaller because light can't get to them, the freefallers then image freezes and slowly fades. Special relativity says the relativity of simultaneity is pronounced at high % of c, would it not be pronounced in an extreme gravitation field? A gravitational field is equivalent to acceleration so... If the curvature of spacetime at the event horizon has an equivalent velocity inwards of c, thereby preventing light escaping, would this not lead the outside observer to see one thing and the freefallers to experience another which special relativity's relativity of simultaneity explains? I say this becaue the light cone escaping the black hole must experience high gravitational fields (i.e equivalence principle) and the free faller continues on their geodesic experienceing 'no' force (save for tidal forces which in the case of a large black hole won't spegetify them just yet). So the _outside_ observer is seeing the effect of the freefaller and the freefallers observable light cone experiencing the equivalence principle which necessarily would cause relativity of simultaneity to become more pronounced. At the event horizon, with an equivalent spacetime curtavure of velocity c, surely this would mean that the outside observer would see no more regardless of what the freefaller observs and all that would be accounted for by relativity of simultaneity. I guess I thought of it as applying relativity of simultaneity to a gravitational field (by way of the equivalence principle) and not just velocity as the train thought experiment did. Is this line of reasoning incorrect - I'm assuming it is - why?
- Thrymr 11y ago> Is this line of reasoning incorrect - I'm assuming it is - why? You're trying to reason about black holes with special relativity, rather than general relativity. Special relativity explicitly ignores acceleration (and equivalently, gravitation). You mention the equivalence principle, which is relevant, but "spacetime curtavure of velocity c" makes no sense, because the curvature leads to acceleration, not velocity directly.
- PaulHoule 11y agoTalk about the moral decay of theoretical physics... This is just like one of those miller lite ads where somebody smacks a beer bottle on the table and on the TV they see a mix of dog racing and bikini mud wrestling. The trouble is that it is so hard to get established that the field is dominated by old fogies; as a kid in the 80s I was aware of this contradiction but it was censored from the physics literature. Instead the greybeards were worried about the information paradox which turned out to be no paradox at all.
- guard-of-terra 11y agoNobody prevents you from postulating your own theory, but those almost always turn out "tinfoil hats".
- jessaustin 11y agoThe trouble is that it is so hard to get established that the field is dominated by old fogies... That's interesting. Do you think it's better or worse in this respect than other sciences or other academic fields?
- mksndz 11y agoThis article reeks of phlogiston
- amongthe 11y agoSo, what if you built a shell around the black hole so that no new radiation whatsoever could reach the black hole, and then dumped enough matter into the black hole to absorb all the Hawking radiation orbiting it, and then jumped in. What would Anne see since you are no longer incinerated (she's inside the shell too)? Also, the article says that for the laws of quantum physics to be preserved, no information can be lost, which is why one clone['s ash] must remain outside the event horizion. But why doesn't the ash fall in the black hole after the one clone gets incinerated, thereby being permanently lost?
- tjake 11y agosounds cool, except before you even got close close to the black hole you would be ripped apart by the tidal forces.
- ceejayoz 11y agohttp://en.wikipedia.org/wiki/Spaghettification http://en.wikipedia.org/wiki/Spaghettification > The point at which tidal forces destroy an object or kill a person will depend on the black hole's size. For a supermassive black hole, such as those found at a galaxy's center, this point lies within the event horizon, so an astronaut may cross the event horizon without noticing any squashing and pulling, although it remains only a matter of time, as once inside an event horizon, falling towards the center is inevitable. For small black holes whose Schwarzschild radius is much closer to the singularity, the tidal forces would kill even before the astronaut reaches the event horizon.
- jessaustin 11y agoThat is the best word for a scientific phenomenon, ever.
- sfdrozdov 11y agoWhat would happen if Anne was holding a rope attached to you? Maybe a better question is what happens when something/someone is straddling the edge of the event horizon?
- entelechy0 11y agoFrom her perspective, you and the rope would burn up against the fire wall
- Frompo 11y agoThis was very confusing, and a prime example of the horrors of popularisation. Watch this talk about the firewall paradox instead, more technical but at least it makes sense! https://www.youtube.com/watch?v=tEtt4A7WsDg https://www.youtube.com/watch?v=tEtt4A7WsDg
- MrBuddyCasino 11y agoInteresting read, but I must say I was a bit disappointed by the ending. Resolving the paradoxon relies on the computational complexity of finding out with which other particle it is entangled with? Somehow that doesn't feel right.
- lottin 11y agoHow can something that doesn't really exist such as space and time possibly be warped? Physicists need to get a grip and understand that their model of the universe is completely wrong. There is no space or time and the universe has no shape.
- xyzzyz 11y ago> How can something that doesn't really exist such as space and time possibly be warped? Think of a surface of a ball: it locally looks flat, but globally is pretty warped. This is an example of a warped 2-dimensional space. The spacetime is just 4-dimensional analogue. http://en.wikipedia.org/wiki/Manifold http://en.wikipedia.org/wiki/Manifold
- drdeca 11y agoDo you have a line of reasoning for that? Models which take spacetime to be able to be warped, /to my understanding/, make what are currently the predictions which are most matched by experiment. I don't know why one would suppose that space and time do not exist, other than as some philosophical idea, but even if one does suppose that, it still appears to work well to model the universe as if they do exist. One would not expect a Berkeleyan Idealist to complain on every article about nuclear fusion because they do not believe that atoms exist. If space and time "do not exist", it seems like speaking of them as if they do would be a useful shorthand, in any case (Provided that they yield a useful model, which they seem to.).
- lottin 11y agoThe reasoning is very simple - If space does indeed exist, it must be somewhere, because everything that exists is somewhere, but space can't be anywhere, because if it's somewhere it must be contained in space. How can something be contained within itself? It can't.
- stromgo 11y ago"Matter contained in space contained in space" might be a problem, but "matter contained in space and space existing directly" should be ok, especially if your alternative is "matter existing directly".
- NoMoreNicksLeft 11y agoAnd if you ever start to think Doctor Who is a wishy-washy-weeny, someone once pissed him off and he did this to them. Moral of the story: don't fuck with time lords.
- deleted 11y ago[deleted]
- monocasa 11y agoSo I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience). How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It seems like you're fighting the upwards curve of a parabola to make that happen, and meanwhile you're releasing pressure from above via hawking radiation.
- contravariant 11y agoIndeed you won't ever be able to ever see something fall into it, but when you get down to it that's just because the light will take an infinitely long time to reach you. There are coordinate systems that are able to describe stuff falling past the event horizon in finite time, you just won't be able to see this happening until you fall into it yourself.
- monocasa 11y agoMy question isn't along the lines of how visible it is to an outside observer, it's more of how can a singularity itself form? It seems like you can't reach infinite density in finite time given gravitational time dilation.
- contravariant 11y agoIt only takes "infinite" time in that particular coordinate system, it takes finite time in other coordinate systems, such as one where you're in orbit around the black hole.
- deleted 11y ago[deleted]
- return0 11y agoIt takes a finite amount of proper time (time experienced by the particle) to reach the singularity.
- amluto 11y agoI don't think this article is representative of current serious thought about black holes. I'm a bit out of date on this stuff, and I was never any sort of expert, but let's see: 1. This reality splitting thing sounds wrong. I've never heard of it. Ignoring quantum effects, if you fall into a black hole and survive crossing the horizon, Anne will see you get closer and closer to the horizon, but she won't see you get there. She won't see you burnt up and she certainly won't collect your ashes. The only fundamental difference between what you see and what Anne sees is that by the time she gets bored of watching, you will only have perceived a tiny amount of time passing. 2. Free fall doesn't protect you from burnination. If the horizon is surrounded by enough fire and brimstone and you free fall through it, you're still going to burn to a crisp. 3. If I remember my old problem set correctly, a black hole big enough for you to live your life in would be truly huge. IIRC the supermassive black hole at the center of the Milky Way would give you about 0.1 ms before you hit the singularity.
- dvdkhlng 11y agoI think the "current serious thought about black holes" is about quantum theoretical effects at the event horizon. Seems there are some problems with reconciling quantum entanglement at the horizon with the fact that nothing can return from beyond the event horizon apart from Hawking radiation. This results in the "Firewall Paradox" [1]. One of the proposed resolutions of the paradox is the claim that directly at the event horizon, invisible to outside observers, a kind of ultra-thin particle inferno exists due to the breakdown of entanglement. This would make it effectively impossible to enter any black hole. (I don't really understand any of this, consult wikipedia and the referenced articles for more correct explanations). [1] https://en.wikipedia.org/wiki/Firewall_%28physics%29 https://en.wikipedia.org/wiki/Firewall_%28physics%29
- jerf 11y ago"This reality splitting thing sounds wrong. I've never heard of it." It's a strange scientific truth filtered through at least one scientist filtered through at least one journalist filtered through at least one editor. The reality is stranger... even if there's no firewall, there's still only one reality, with all the observers seeing all the different things. As for your 2, yes, it is likely there isn't a single black hole in the universe that meets our criteria for being able to "safely" fall into it, but at least in theory such a beast could exist, and barring any other unexpected existence failures, such a beast may exist in the far, far, far future. There's a lot of future and most of it is pretty boring....
- peter303 11y agoThere are minimal tidal forces for very large black hole. You would not be torn apart approaching or crossing the event horizon then. You would be unable to leave or signal out of the hole.
- peter303 11y agoNote the observable universe has an event horizon 13.8B years in time or 92GLY wide in space which we cannot communicate across. Some speculate the observable universe may also have the mass-energy of a black hole with an event horizon of that size. But the observable universe is not a singularity with all the mass-energy concentrated at a infinitely small "center". So in conclusion the observable universe SOME of the characteristics of being inside a black hole, but not all of them.
- gus_massa 11y agoI really don't understand this sentence: > So Anne takes her bit, A, and puts it through her handy entanglement-decoding machine, which spits out an answer: either B or C. (Note: I have a Ph.D. in Math and half a major in Physics that include a few quantum mechanics curses (for example, with the Sakurai book)) What is a entanglement-decoding machine? You cant use entanglement to send information. Just repeat after me: You cant use entanglement to send information. This is one of the most common misunderstandings about entanglement. When you make the measurement and get the collapse, you only get a random value (with a weighted probability). It's not possible to use that to get information about B or C.
- pcl 11y agohalf a major in Physics that include a few quantum mechanics curses I'm sure you meant "courses" but I like it more the way you wrote it.
- golgappi 11y agoThe article doesn't say that information from B or C is useful. All it explains is only 2 particles can be entangled with each other. So either A is entangles with B or it is entangled with C, not both. Which means that either Anne's reality is correct, or yours. The whole thing about the decoding machine is just described to oversimplify it for the benefit of the masses.
- gus_massa 11y agoNear the bottom of the article: > One clue might lie in Anne's decoding machine. Figuring out which other bit of information A is entangled with is an extraordinarily complicated problem. [...] In 2013 they calculated that, even given the fastest computer that the laws of physics would allow, it would take Anne an extraordinarily long time to decode the entanglement. By the time she had an answer, the black hole would have long evaporated, disappearing from the universe and taking with it the threat of a deadly firewall. The "machine" is an oversimplification, but I don't understand the equivalent experiment that can distinguish between B and C. Also, there are more complicated situations. You can entangle 3, 4, ... or more particles http://en.wikipedia.org/wiki/Multipartite_entanglement http://en.wikipedia.org/wiki/Multipartite_entanglement Usually the discussions are only about entanglement of 2particles, because that is weird enough, but the math for more particles is just a little more complicated.
- jkot 11y agoFalling into a black hole is booooring. I want technical details about ship which can deliver human near the event horizon.
- helyka 11y agoI guess I've always misunderstood blackholes. I was under the impression that they were simply a vacuum created as a by product of the every expanding "space". Sure they are sucking things up and growing, but space is always expanding.
- joshdance 11y agoThought it was weird in Interstellar that Cooper survived getting pulled into the black hole. Interesting that surviving is one of the 2 possibilities.
- yellowapple 11y agoDude, spoilers! :) But yeah, what I'd love to know is how he got out. Did it leave him behind when it evaporated (due to Hawking radiation)? Is Cooper a "particle" in that context that was emitted as Hawking radiation? Crazy stuff.
- nilkn 11y agoIt's hard to say exactly why as I'm not a scientist, but I find the credibility of this piece extremely suspect. It seems to be making a number of sensational claims (splitting of reality?) and I don't get the feeling that the author understands this material on anything other than a completely amateur level. Also, this seems to commit the famous mistake of thinking that you will be ripped to shreds by tidal forces the second you cross the event horizon. This is well-known to be false. For sufficiently large black holes you can peacefully pass beyond the horizon (unless there's something else going on, like a firewall).
- yellowapple 11y ago> For sufficiently large black holes you can peacefully pass beyond the horizon (unless there's something else going on, like a firewall). The article addresses this by pointing out that the "tidal forces" in question are only noticeable for smaller black holes (at which point "spaghettification" - which is, by the way, the formal technical term for this phenomenon - occurs); for larger ones, spaghettification forces are too small to even be felt. The Wikipedia article on spaghettification [0] has more details. The mechanics are similar to those of a body's Roche limit (the point where the tidal forces of one body will disintegrate a satellite body held together only by its own gravity; i.e. the reason why the gas giants tend to have rings). Granted, my own understanding of astrophysics isn't a whole lot better than an amateur level, either, but the article doesn't seem all that inconsistent with how people who do have expertise in astrophysics have described these sorts of things. [0]: https://en.wikipedia.org/wiki/Spaghettification https://en.wikipedia.org/wiki/Spaghettification
- nilkn 11y agoYou're right, I glossed over that the article does address that point. So I retract that criticism. I'm honestly at this point just exceedingly skeptical of mostly everything I read about theoretical physics unless it's coming directly from an expert.
- yellowapple 11y agoTo be fair, I'm pretty skeptical of stuff about black holes even when they do come from experts, since there's so much contradiction between general relativity and quantum mechanics in this particular context, and experts more well-versed in one field over the other will try to use that field's explanations over the other's. Black holes are fuckin' weird.
- selimthegrim 11y agoDidn't Patrick Hayden write a paper about this stating it was essentially an unphysical situation in the lifetime of the universe? I seem to remember this from the fundamental physics prize lectures....