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Einstein and his peers were resistant to black holes
- IIAOPSW 2y agoGiven he was clearly convinced in the end by sound arguments, was it really irrational or was he just a hard sell for good reasons?
- jerf 2y agoI think there's plenty of reasons to be a hard sell on relativity's take on black holes. After all, it's still a plenty hard sell today. The evidence that things that looks like black holes on the outside exist is pretty solid, but the evidence we have about the insides is zero. I don't particularly "believe" in the relativity take on black holes either, which is to say, I have very high confidence that a real and effectively-correct theory of quantum gravity will remove the singularities. I'd love to pull off the trick of being extremely easy to convince about true things and only true things, and being very stubborn about everything else, but that's basically epistemologically begging the question. It's too much to ask of anyone.
- mistermann 2y ago> It's too much to ask of anyone. Ternary logic is available (physically at least).
- zeroxfe 2y ago> I have very high confidence that a real and effectively-correct theory of quantum gravity will remove the singularities. What gives you this confidence?
- vecter 2y agoThe general belief that singularities are “unphysical” and reflect a flaw in our models than actual reality. Hard to prove definitely right now of course.
- hparadiz 2y agoI always thought the concept of a singularity here was just to make the math slightly simpler. That is to say that a black hole is still a spherical body with a set diameter. We just can't see it so there's no way to verify other than the fact that we can see the border of the event horizon.
- atombender 2y agoAs far as I know, that very much isn't the case. The singularity is a result of the math, not a trick to simplify it. My understanding is that many researchers do think it's a "placeholder" representing our lack of insight into how physics behave at those scales, and not a real physical phenomenon, and that it will one day be possible to work past it. I believe Kerr and Penrose (both of whom did some of the most foundational work on black holes) believe it's a mathematical artifact.
- hparadiz 2y agoMy random thoughts on this: - Is the math referring to the center of gravity as the singularity? Because even a sub black hole mass object would have that. - Why is there an assumption that just after a mass becomes a black hole the matter inside it suddenly compresses further when the actual gravity of the object has only slightly increased? - Is there a maximum density of matter in the universe and if the black hole even reaches that? - Wouldn't you need that number to be infinite if the black hole itself is infinitely small? - If the black hole does have a mass inside it... Do the light particles trapped inside the black hole form a blanket around the existing matter?
- Dylan16807 2y ago> - Why is there an assumption that just after a mass becomes a black hole the matter inside it suddenly compresses further when the actual gravity of the object has only slightly increased? Yeah, that seems like an important thing to address. Black holes don't even have to be high density, or have much matter in the center at the time of formation. If you arrange enough big chunks of metal into a spherical-shell constellation, then drop them all toward their mutual center, they can reach the threshold to become a black hole before they even start colliding. What happens around that time, and what specifically does "singularity" mean (because I see people using it in very different ways). > - Is there a maximum density of matter in the universe and if the black hole even reaches that? > - Wouldn't you need that number to be infinite if the black hole itself is infinitely small? Black holes are the benchmark for maximum density. The event horizon is always exactly at the limit. By "black hole itself" do you mean something other than the event horizon? But that maximum density depends on size, smaller things can be denser and bigger things have to be less dense.
- ikiris 2y agothe dunning kruger effect
- jerf 2y agoTo the best of my knowledge, none of the competing theories for integration have singularities in them. It is difficult to know what a "singularity" would look like in a universe that doesn't seem to have 0-dimensional mathematical points in it. It isn't that surprising that continuous theories have singularities in them. Reality doesn't seem to be continuous in the sense that real numbers are. It is unknown if Navier-Stokes can develop singularities in finite time, but in the real universe it won't matter because they won't lead to singularities in the real universe because it is ultimately just an approximation. "Interesting things" may happen around whatever those conditions are but nothing will be accelerated to infinite speed in the real universe. It is another theory that is a real-number-based continuous approximation made useful by the fact that real numbers are easier to do math with than physical quantities, but the real universe does not have plain real numbers in it. (This is subtly different than the controversial statement that it isn't made out of real numbers at all. But it does not have "plain" real numbers. You certainly can not expect to pull out a microscope and peer at the universe at a scale of 10^-10000 meters and see a universe that behaves exactly the same, just at a smaller scale. Our universe is definitely not scale-invariant.) I think this is likely to be a rather accurate metaphor. To be honest, I don't see a lot of positive reason to assume that the singularities are going to be "real". I think physicists initial reactions to the idea were correct and remain correct. I think the reasons why people think otherwise are emotional rather than logical. They've gotten attached to all the stories around black holes and all the science fiction and all the crazy ideas (parallel universes! white holes! wormholes!) and a general sense of "woo" that I for one do not find very appealing, and what people are reacting to is the loss of that, not the idea that the universe probably won't have any infinitely dense points... when the universe doesn't seem to have any points in it in the first place. (To forstall another common rabbit trail, I don't think the universe is continuous... but that doesn't mean I automatically think it must be discrete: https://news.ycombinator.com/item?id=38433917 https://news.ycombinator.com/item?id=38433917 )
- zmgsabst 2y agoAlternative: Quantum theories arise because the singularities in black holes create a topological regime within their vicinity — and for SMBs, that’s a whole galaxy. I think it’s interesting that different people feel different things are “natural”.
- datavirtue 2y agoIn layman's terms, isn't the take that the area of a black hole is devoid of space? Therefore you can never see or measure it except for forces generated by it within our space.
- ajkjk 2y agoThe claim of general relativity is that a black hole is a singularity in spacetime, meaning that space effectively "ends" there. A very crude model would be cutting a hole out of fabric and then sewing the circle up into a point. The area of the hole is "gone" --- it's not like it's there and you can't see it, it's just not there. I guess that it is what you mean by "devoid of space". Then the rest of the fabric is bent in weird ways around the fact that there's a chunk missing, which in physics manifests as as everything being pulled towards it (and there is a point, the event horizon, at which things are no longer possible to interact with, like you're too deep in the hole to get out again.
- ajkjk 2y agoI see no epistemic problem with a singularity existing. After all electron are singularities in the EM field, of a sort. Why shouldn't a lot of electrons together form a giant singularity?
- Analemma_ 2y agoI'm not at all an expert in this, but my limited understanding is that electrons are only "singularities" in classical EM; in quantum field theory they're just solitons of the underlying quantum field and can be analyzed with no infinities present. We haven't found a QFT equivalent for gravity yet, but I think the broad consensus is that the gravitational singularities will disappear once we do.
- ajkjk 2y agoAfaik even in qft they are effectively singularities, but I'm not an expert in that yet. It's not that they are infinities, it's that they're point discontinuities in the A field.
- Jensson 2y agoIn qft there are no singularities, everything are fields. Particles are just such fields, a singularity in qft would mean you have a Dirac delta shaped field, I don't think such a field exists in reality and I don't think many working physicists would believe in them either. The big reason they can't even come up with math for the black hole singularities is just because the theory doesn't support working with such Dirac shaped fields. Edit: When they say electrons doesn't have a size, what they mean is that there is no limit to how small you can make an electron, not that it is always compressed into a point.
- antognini 2y agoTruth be told, we don't really know that electrons are singularities in the EM field. Classically that's the case, of course. But in QFT, as you start to probe to shorter distances (and higher energies), our theories eventually break down because gravitational effects cannot be ignored. (For instance, how do you describe the EM field at distances shorter than a Planck length? The energies needed to probe to that limit would collapse the system into a black hole.)
- bmitc 2y agoThat doesn't really follow, because it seems that people were and are wanting black holes to be something else that they are both not observed to be and not described by any theory of them. Also, I think it gets lost in physics that theories are models of reality. They are not reality themselves. General relativity is about as good as a model gets. Alongside the standard model, it's one of the most tested models around. A singularity has a meaning in physics in terms of math, which is dividing by zero or something approaching zero in the denominator. A singularity has a physically modeled aspect in that it's the name assigned to whatever becomes of the matter that gets squished down. A black hole is effectively not a thing in itself but rather an effect of what happens when mass is squeezed beyond all known limits. What's inside a black hole is not the only thing in the universe we can't see. The actual universe is far bigger than the visible universe, but we can't see outside of the visible universe due to how light works. So it basically doesn't even matter what's going on there. The question is if anything happening at the boundaries can tell us something about that which we can't see. It doesn't make sense to dismiss what we observe on the outside based upon what we literally cannot know of the inside. And after all, general relativity is a classical theory. Is it really all that "weird"? It all feels somewhat mechanical and natural as you start learning it and turn off your biased intuition.
- Jensson 2y agoWe have observed one black hole from the inside, the big bang. The reality we see today doesn't really look like what general relativity math says the inside of a black hole should look like. The pro singularity people must then believe the black hole evaporated really quickly into a big bang to rejoin the out universe, but a more rational answer is that the big bang is what happens inside black holes rather than a singularity forming. Space inflation after the big bang would just be the black hole expanding as it ate more material in its near vicinity.
- xorbax 2y agoThat seems more like a fun sci-fi speculation
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- hubgrei 2y ago[dead]
- somat 2y agoI am halfway convinced a singularity will never actually reach the singularity form due to time dilation effects. that is, it ends up taking forever to actually reach zero size(not that time or space have much meaning inside such an environment)
- rbanffy 2y agoYou should also never see anything falling into a black hole because time is so stretched near the horizon it’d take almost literally forever to reach it. The bright light we see is the tidal force tearing matter apart as it approaches the horizon.
- burnished 2y agoRead the article, resistance came from a sense of personal repugnance and concluded in the form of personal attacks. It was irrational.
- empath75 2y agoThere was one insulting dismissal of one physicists grasp of physics at one point, but Einstein didn't end the conversation with LeMaitre then and eventually conceded that he was wrong, so it wasn't a 'conclusion', either.
- burnished 2y agoThis occurred over decades. It was not a simple insult mid conversation.
- NoMoreNicksLeft 2y agoFor any given radical-but-rational concept, people must instantaneously accept the proposition (instantaneously being less than 0.1 seconds after becoming aware of the concept). Anything else constitutes science denialism.
- mistermann 2y agoThe Scientismic Method is powerful, and broadly distributed!
- alkyon 2y agoI wonder if any mass could even colapse beyond Planck length? Maybe theory unifying quantum mechanics with Einstein's general relativity would have more definite answers.
- dang 2y agoHow about we finesse that by taking out the baity bit from the title above.
- shadowgovt 2y agoTBH, "irrationally" is a value judgment that I can't agree with. Einstein's approach to physics was to reason out the consequences of observable phenomena. He approached understanding of the nature of the speed of light by realizing that a universe where you could travel as fast as (or faster than) a light ray would have consequences that we didn't see. So when the math tells him "gravity causes some regions of space to blow up to become inescapable," and we hadn't seen black holes yet, I think his first intuition being that we'd missed a trick that made the math fail to match reality was a fine intuition. Math is only useful to physics to the extent that it actually models reality, and not all the extrapolations it makes turn out to have practical grounding; sometimes chasing the extrapolation reaches a contradiction that demands adjustments to math to fix the model. Chasing such adjustments in light of evidence is how we reached relativity in the first place.
- rightbyte 2y ago> He approached understanding of the nature of the speed of light by realizing that a universe where you could travel as fast as (or faster than) a light ray would have consequences that we didn't see. A sound wave could be outrun though. I don't see any step in why a such an philosofical approach would apply to light but not sound?
- xorbax 2y agoBecause photons behave in a fundamentally different way than sound. See the Michelson-Morley experiment.
- shadowgovt 2y agoThe relevant quote from his Autobiographical Notes is "...a paradox upon which I had already hit at the age of sixteen: If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as an electromagnetic field at rest though spatially oscillating. There seems to be no such thing, however, neither on the basis of experience nor according to Maxwell's equations. From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest. For how should the first observer know or be able to determine, that he is in a state of fast uniform motion? One sees in this paradox the germ of the special relativity theory is already contained." In short, he realized that if things could travel at lightspeed, we should be moving relative to something out there at lightspeed, so we should be experiencing its light as this weird "electromagnetic field at rest though spatially oscillating" (i.e. a field coming from apparently nowhere that changes in intensity as you move around in space but not in time)... but nobody had ever seen that phenomenon. Einstein seems to have put a lot of stock in "If physics allows it, we should be seeing it" as a razor of sorts, so it makes sense that when the math said black holes should exist but they hadn't been seen, his default position was to be skeptical of the math and the intuition. Such skepticism had served well in the past for him. (Worth noting for completeness: The "variable speeds of light predict stationary waves, but we never observe such things" objection is just one objection that comes up in Einstein's thought experiments. A more complete treatment of the subject is given in at https://sites.pitt.edu/~jdnorton/Goodies/Chasing_the_light/ https://sites.pitt.edu/~jdnorton/Goodies/Chasing_the_light/).
- baxtr 2y agoI don’t want to open another box, but how exactly do people distinguish between rational vs irrational behavior? You might define it as quick system 1 vs thoughtful system 2 reaction. But I’m pretty sure Einstein had thought this through and had good, rational reasons at that time to “resist” the idea of black holes.
- lucianbr 2y agoThere may be exceptions, but most of the time I find people call "irrational" any reasoning they disagree with.
- lukan 2y agoRationality is apparently relative.
- circuit10 2y agoIt’s still possible to have biases when thinking something through deeply
- baxtr 2y agoAbsolutely. But then what exactly is being rational
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- treflop 2y agoI think pretty much everyone is rational. However, our access to facts and information is vastly different between two different people. That's because we grow in different spaces, meet different people, and have vastly different experiences. Then you fall into this trap where you think you are right. You ARE right, but only in the context of your experience. Since it's rarely possible to ever know if you are universally right, you have to keep an open mind, which can be difficult.
- MacsHeadroom 2y agoAn irrational belief is one you did not come to through reason. Irrational doesn't mean bad or wrong. It just means it did not come from a rationale. Many beliefs we have are presuppositions which we demand strong rationale for changing, despite not needing similar rationale to arrive at the presupposed belief. Believing the earth is flat because it looks flat is an example of an irrational belief practically everyone holds until taught otherwise. Some people hold onto the belief even after being given good reason to abandon it. We call that irrational behavior.
- brcmthrowaway 2y agoWhat is the function of the blackholes in a rational universe?
- akira2501 2y agoMaybe enforcing the second law of thermodynamics? Or they're a consequence of the same. It's a region of space where the conditions that existed before the big bang have ostensibly reestablished themselves, which is why it appears as a 2d boundary phenomenon to us. I am a total crank.
- brcmthrowaway 2y ago1/1,000,000 cranks will be right.
- pixl97 2y agoThere are theories that our universe is the inside of a black hole. >https://en.wikipedia.org/wiki/Black_hole_cosmology https://en.wikipedia.org/wiki/Black_hole_cosmology If that is the case, then black holes are giant entropy recycling machines.
- newpavlov 2y agoPlenty of physicists are still "resistant" to the idea of black holes having a real singularity. The recent Kerr paper [0] only adds fuel to this resistance with its hilarious statement "Faith, not science!" about singularity proponents. [0]: https://arxiv.org/abs/2312.00841 https://arxiv.org/abs/2312.00841
- lawlessone 2y agoInfinite density is pretty crazy though. Would it change much from the outside perspective if there was something more like an ultra compact neutron star at the center?
- newpavlov 2y agoA very simplified idea is that the denser you get, the slower time flows (for an "outside" observer). So while for an "inner" observer density rises "fast" to the point of singularity, for an "outside" observer time just freezes inside the forming black hole. Finally, if there is a way for black holes to "evaporate" (e.g. Hawking radiation), the "inner" observer will be able to observe shrinking black hole.
- pdonis 2y agoNo, this doesn't work. The "slower time flows" you is an optical illusion caused by the curvature of spacetime. It is not a way to avoid the formation of a black hole.
- newpavlov 2y agoAre you talking about the Hawking-Penrose theorems? Have you read the Kerr paper?
- pdonis 2y ago> Are you talking about the Hawking-Penrose theorems? No. Your wrong claim about the slowing of time flow has nothing to do with those. > Have you read the Kerr paper? Yes. It doesn't say anything like what you were saying. I have commented on it elsewhere in this discussion.
- umvi 2y agoThis article seems like a rehash of the recent Veritasium video: https://www.youtube.com/watch?v=6akmv1bsz1M https://www.youtube.com/watch?v=6akmv1bsz1M For example, compare the picture of Karl Schwarzschild in the article to 7:54 in the Veritasium video. Just a coincidence?
- empath75 2y agohttps://today-in-wwi.tumblr.com/post/144234528063/karl-schwarzschild-dies https://today-in-wwi.tumblr.com/post/144234528063/karl-schwa... Looks like the BBC used this photo as reference for the drawing.
- rosmax_1337 2y agoTo this day I believe black holes remain a mostly theoretical phenomena. Which also happens to deal with infinity-mathematics in the singularity, something we don't see in reality otherwise. Yes, observations have been made to their advantage, through LIGO and more recently the image from 2022 of a black hole made by the Event Horizon Telescope. But I would stress that the ""image"" is much more complex than simply a photo from really good ""telescope"", it's a image made of combined data from radio telescopes all around the world. There is enough weird hoops that they need jump through that the observation can reasonably be doubted in my opinion, which isn't to say that what they've attempted is awesome and inspiring. Please correct me if you have other information.
- empath75 2y agoThey've been detected with gravity waves, radio telescopes and optical telescopes and explain a wide variety of phenomena in the center of galaxies. What evidence would you require to confirm that they exist?
- pdonis 2y agoThe objects we have detected look like classical GR black holes, yes. The problem is that, theoretically, there are other possible objects that look like classical GR black holes from the outside for a very, very long time, but still aren't classical GR black holes. We have no direct way of telling from observation whether the objects we have detected really are classical GR black holes, or whether they are one of the other possibilities.
- pdonis 2y ago> black holes remain a mostly theoretical phenomena The fact that there are compact objects in our universe that, from the outside, look like the black holes that GR predicts, is not "theoretical", it's observation. The theoretical question is whether these objects really are classical GR black holes "all the way down", so to speak, or whether there is some new physics that comes into play deep inside them (which many physicists think will involve some form of quantum gravity) that changes things. Even if the latter is the case, the objects might still look like classical GR black holes from the outside for a very, very long time, on the order of the Hawking evaporation time (10^67 years for a one solar mass hole, and the time goes up as the cube of the mass). So for all practical purposes, treating them as classical GR black holes works fine now and for the foreseeable future.
- sega_sai 2y agoWhen there is no experimental evidence for black holes, it makes perfect sense to be resistant/skeptical to new type of objects with solutions involving infinities (singularity). Whether that's being irrational or not is up to debate. I'd say that's a good prior when there is no data (as there wasn't at the beginning of 20th century).
- davidcuddeback 2y agoCase in point: the same equations predict white holes, which today are widely believed to not exist.
- chgs 2y agoI’ve never seen one before — no one has — but I’m guessing it’s a white hole.
- iamgopal 2y agoWhat is white hole ?
- Retric 2y agoA region of space time matter/light/information can exit but you can’t send anything to. https://en.wikipedia.org/wiki/White_hole https://en.wikipedia.org/wiki/White_hole
- jyunwai 2y agoA person with a better astronomy background can jump in, but I'll start by quoting a couple trusted astronomy publications. In short, a white hole is an astronomical object with the property that light cannot enter it. From the Universe Today (at https://www.universetoday.com/122715/what-are-white-holes/ https://www.universetoday.com/122715/what-are-white-holes/ ): "Black holes are places in the Universe where matter and energy are compacted so densely together that their escape velocity is greater than the speed of light. […] Fully describing a black hole requires a lot of fancy math, but these are real objects in our Universe. […] So then what’s a white hole? "White holes are created when astrophysicists mathematically explore the environment around black holes, but pretend there’s no mass within the event horizon. What happens when you have a black hole singularity with no mass? […] "Now if white holes did exist, which they probably don’t, they would behave like reverse black holes – just like the math predicts. Instead of pulling material inward, a white hole would blast material out into space like some kind of white chocolate fountain. […] One of the other implications of white hole math, is that they only theoretically exist as long as there isn’t a single speck of matter within the event horizon. As soon as single atom of hydrogen drifted into the region, the whole thing would collapse." And from Space.com (at https://www.space.com/white-holes.html https://www.space.com/white-holes.html ): "White holes are theoretical cosmic regions that function in the opposite way to black holes. Just as nothing can escape a black hole, nothing can enter a white hole. […] "To a spaceship crew watching from afar, a white hole looks exactly like a black hole. It has mass. It might spin. A ring of dust and gas could gather around the event horizon — the bubble boundary separating the object from the rest of the universe. But if they kept watching, the crew might witness an event impossible for a black hole — a belch. "Physicists describe a white hole as a black hole's "time reversal," a video of a black hole played backwards, much as a bouncing ball is the time-reversal of a falling ball. While a black hole's event horizon is a sphere of no return, a white hole's event horizon is a boundary of no admission — space-time's most exclusive club. No spacecraft will ever reach the region's edge. Objects inside a white hole can leave and interact with the outside world, but since nothing can get in, the interior is cut off from the universe's past: No outside event will ever affect the inside."
- VagabundoP 2y agoThis stuff was cosmic horror to all these folk. It caused existential crisis when you try imagine what is happening in and around a black hole. I'm not surprised they did everything they could to deny and disprove it. Most would have had religious convictions that were really challenged by the physical reality of the universe.
- dhosek 2y agoThe edited headline we have now makes it sound like twentieth-century physicists had some sort of anti-gravity thing going on.
- pharrington 2y agoWhy was "irrationally" edited out of the submission title?
- CHB0403085482 2y agoIf you prefer the video version of the theory.... https://www.youtube.com/watch?v=6akmv1bsz1M https://www.youtube.com/watch?v=6akmv1bsz1M