8 ms·

Given 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 ago
I 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 ago
    The 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 ago
      I 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 ago
        As 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 ago
        My 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.
    - vlovich123 2y ago
      All we know is that we’ve made a lot of crazy predictions about the structure and behavior of black holes well before we measured them and so far they’ve aligned remarkably close to the predictions. If there is a difference, it’s about the interior not how it shows up in our universe. And since we can never see inside the black hole, any alternative model would have to better explain some phenomena our existing models can’t or be even easier than relativity and explain the same things. We know string theory is hard to make consistent and it struggles to create falsifiable experiments. I would bet on relatively remaining a very very long time until we figure out how to unify quantum and relativity.
  - ikiris 2y ago
    the dunning kruger effect
  - jerf 2y ago
    To 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 ago
  Alternative: 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 ago
  In 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 ago
    The 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 ago
  I 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 ago
    I'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 ago
      Afaik 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 ago
        In 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 ago
    Truth 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 ago
  That 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 ago
    We 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 ago
      That seems more like a fun sci-fi speculation
      - 2y ago
- hubgrei 2y ago
  [dead]
- somat 2y ago
  I 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 ago
    You 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 ago
Read the article, resistance came from a sense of personal repugnance and concluded in the form of personal attacks. It was irrational.
- empath75 2y ago
  There 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 ago
    This occurred over decades. It was not a simple insult mid conversation.
NoMoreNicksLeft 2y ago
For 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 ago
  The Scientismic Method is powerful, and broadly distributed!
alkyon 2y ago
I 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 ago
How about we finesse that by taking out the baity bit from the title above.

jerf 2y ago

I 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 ago
  The 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 ago
    I 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 ago
      As 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 ago
        My 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.
  - vlovich123 2y ago
    All we know is that we’ve made a lot of crazy predictions about the structure and behavior of black holes well before we measured them and so far they’ve aligned remarkably close to the predictions. If there is a difference, it’s about the interior not how it shows up in our universe. And since we can never see inside the black hole, any alternative model would have to better explain some phenomena our existing models can’t or be even easier than relativity and explain the same things. We know string theory is hard to make consistent and it struggles to create falsifiable experiments. I would bet on relatively remaining a very very long time until we figure out how to unify quantum and relativity.
- ikiris 2y ago
  the dunning kruger effect
- jerf 2y ago
  To 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 ago
Alternative: 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 ago
In 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 ago
  The 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 ago
I 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 ago
  I'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 ago
    Afaik 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 ago
      In 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 ago
  Truth 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 ago
That 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 ago
  We 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 ago
    That seems more like a fun sci-fi speculation
    - 2y ago
hubgrei 2y ago
[dead]
somat 2y ago
I 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 ago
  You 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 ago

Read the article, resistance came from a sense of personal repugnance and concluded in the form of personal attacks. It was irrational.

empath75 2y ago
There 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 ago
  This occurred over decades. It was not a simple insult mid conversation.

NoMoreNicksLeft 2y ago

For 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 ago
The Scientismic Method is powerful, and broadly distributed!

alkyon 2y ago

I 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 ago

How about we finesse that by taking out the baity bit from the title above.