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FWIW, it's not clear that SgA* is actually a canonical black hole (nor that even such a thing truly exists in nature.) The EHT image is taken as confirmation b

FWIW, it's not clear that SgA* is actually a canonical black hole (nor that even such a thing truly exists in nature.) The EHT image is taken as confirmation but the accuracy of that technique has been called into question: https://arxiv.org/abs/2205.04623 https://arxiv.org/abs/2205.04623 Edit: In response to the downvotes, here are 2 very good sources who at least argue against the existence of singularities and their event horizons. 1: https://arxiv.org/pdf/2312.00841 https://arxiv.org/pdf/2312.00841 2: https://uncnewsarchive.unc.edu/2014/09/23/carolinas-laura-mersini-houghton-shows-black-holes-exist/ https://uncnewsarchive.unc.edu/2014/09/23/carolinas-laura-me... I don't know exactly when science discussion turned into rigid dogma enforcement but we are certainly in that era presently.

sergent_moon 2y ago
I think some of the apparently dogmatic attitude is from exhaustion. Usually (I'm not implying you) someone calling commonly accepted science into question are just waiting for a moment to drop something about Jesus, or Chemtrails or some other nonsense.
- dotnet00 2y ago
  Or even more commonly with astronomy, are misinterpreting the material to prop up their pop science influenced preconceived notions. I think everyone in the hard sciences has had some experience of having to deal with someone with no technical insight, arguing a point that has already been discussed in far more detail by experts and claiming that scientists are just being dogmatic because they don't care to repeat the same points over and over again.
dekhn 2y ago
Neither of those are "very good sources". Further, they are basically mathematical modelling papers. We have a lot of experimental evidence about the nature of black holes. If you argument is just "black holes might not be a true singularity", well, nobody is strongly disagreeing with that, we just don't have evidence or good support for alternative models. People aren't being dogmatic, they just don't have any better models that explain the observations.
- TheBlight 2y ago
  Laura Mersini-Houghton and Roy Kerr seem like very good sources to me. Are you familiar with their work? It seems not. A "black hole" implies a singularity behind an event horizon not even light can escape from. There isn't any proof that such a thing exists in nature. You're correct in saying that we see the indirect gravitational effects of something that doesn't fit any model our imaginations have conjured up to date except for "black hole." That doesn't mean it's clear that black holes are a real thing.
  - wizzwizz4 2y ago
    > You're correct in saying […] a real thing. This is, indeed, how science works. "All models are wrong", as they say. I'm not sure what you're trying to push back against.
    - TheBlight 2y ago
      That would be perfectly lovely for me if that was actually the attitude of most people weighing in on these discussions. But in practice, when it's insinuated that a more beloved sci-fi model may perhaps be incorrect/incoherent it's met with people being upset that it's being pointed out.
      - deleted 2y ago
        [deleted]
      - dekhn 2y ago
        I would not be upset if black holes are not singularities although I would be surprised if they didn't have event horizons. IIUC you're basically talking about this: https://en.wikipedia.org/wiki/Nonsingular_black_hole_models https://en.wikipedia.org/wiki/Nonsingular_black_hole_models which don't seem to be fully mainstream, nor supported by any observed evidence.
        TheBlight 2y ago
cthalupa 2y ago
Kerr's paper is quite specifically about not believing in singularities, not about not believing in black holes. It's hardly a controversial opinion in the science community to believe that singularities in black holes are an artifact of our incomplete mathematical representation of how gravity works. That is not the same as suggesting that black holes or event horizons don't exist. Kerr's solution to the field equations involves two event horizons to begin with, and his argument in the new paper is based on Kerr black holes and explicitly talks about event horizons in multiple places. I'm very confused as to why you believe that paper provides significant argument as to why calling SgA* a black hole would be jumping the gun.
- TheBlight 2y ago
  See this comment: https://news.ycombinator.com/item?id=40381317 https://news.ycombinator.com/item?id=40381317

sergent_moon 2y ago

I think some of the apparently dogmatic attitude is from exhaustion. Usually (I'm not implying you) someone calling commonly accepted science into question are just waiting for a moment to drop something about Jesus, or Chemtrails or some other nonsense.

dotnet00 2y ago
Or even more commonly with astronomy, are misinterpreting the material to prop up their pop science influenced preconceived notions. I think everyone in the hard sciences has had some experience of having to deal with someone with no technical insight, arguing a point that has already been discussed in far more detail by experts and claiming that scientists are just being dogmatic because they don't care to repeat the same points over and over again.

dekhn 2y ago

Neither of those are "very good sources". Further, they are basically mathematical modelling papers. We have a lot of experimental evidence about the nature of black holes. If you argument is just "black holes might not be a true singularity", well, nobody is strongly disagreeing with that, we just don't have evidence or good support for alternative models. People aren't being dogmatic, they just don't have any better models that explain the observations.

TheBlight 2y ago
Laura Mersini-Houghton and Roy Kerr seem like very good sources to me. Are you familiar with their work? It seems not. A "black hole" implies a singularity behind an event horizon not even light can escape from. There isn't any proof that such a thing exists in nature. You're correct in saying that we see the indirect gravitational effects of something that doesn't fit any model our imaginations have conjured up to date except for "black hole." That doesn't mean it's clear that black holes are a real thing.
- wizzwizz4 2y ago
  > You're correct in saying […] a real thing. This is, indeed, how science works. "All models are wrong", as they say. I'm not sure what you're trying to push back against.
  - TheBlight 2y ago
    That would be perfectly lovely for me if that was actually the attitude of most people weighing in on these discussions. But in practice, when it's insinuated that a more beloved sci-fi model may perhaps be incorrect/incoherent it's met with people being upset that it's being pointed out.
    - deleted 2y ago
      [deleted]
    - dekhn 2y ago
      I would not be upset if black holes are not singularities although I would be surprised if they didn't have event horizons. IIUC you're basically talking about this: https://en.wikipedia.org/wiki/Nonsingular_black_hole_models https://en.wikipedia.org/wiki/Nonsingular_black_hole_models which don't seem to be fully mainstream, nor supported by any observed evidence.
      - TheBlight 2y ago

cthalupa 2y ago

Kerr's paper is quite specifically about not believing in singularities, not about not believing in black holes. It's hardly a controversial opinion in the science community to believe that singularities in black holes are an artifact of our incomplete mathematical representation of how gravity works. That is not the same as suggesting that black holes or event horizons don't exist. Kerr's solution to the field equations involves two event horizons to begin with, and his argument in the new paper is based on Kerr black holes and explicitly talks about event horizons in multiple places. I'm very confused as to why you believe that paper provides significant argument as to why calling SgA* a black hole would be jumping the gun.

TheBlight 2y ago
See this comment: https://news.ycombinator.com/item?id=40381317 https://news.ycombinator.com/item?id=40381317