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We have observed matter falling into a black hole. We've watched "hot spots" in orbit of a black hole in the accretion disk shine their light at us as they orbi

We have observed matter falling into a black hole. We've watched "hot spots" in orbit of a black hole in the accretion disk shine their light at us as they orbited the black hole. We've watched as the orbit got tighter and tighter and the light was dimmed by gravitational red shifting, then we've watched the light blink out and disappear as the blob of gas fell below the event horizon. The evidence for the existence of black holes is incredibly strong at the moment. In fact in some ways it's stronger than the evidence for the existence of atoms about a century ago. Nobody except cranks or extreme contrarians seriously disputes the theory these days.

roywiggins 8y ago
I believe the argument is that event horizons exist but inside is not a singularity, but an eternally collapsing mass of the original star. From the point of view of the star, it does collapse all the way, but from our point of view that final singularity collapse is in the indefinite future. https://en.m.wikipedia.org/wiki/Magnetospheric_eternally_collapsing_object https://en.m.wikipedia.org/wiki/Magnetospheric_eternally_col...
- roywiggins 8y ago
  Update: I am mistaken. The classic GR black hole behaves this way. MECOs supposedly never fully collapse into a singularity, even for infalling observers. That's the difference. I rather think we'd have noticed the difference from LIGO gravitational wave measurements of BH mergers, but maybe not?
perl4ever 8y ago
From your point of view, if so-called black holes are "fuzzballs"[1] is that a vindication or a refutation of the existence of black holes? Without a deep understanding of physics, I have the general attitude that infinities must be a mathematical error, and therefore something must stop black holes from collapsing totally, but whether they "exist" is only a matter of definitions. [1]https://en.wikipedia.org/wiki/Fuzzball_(string_theory) https://en.wikipedia.org/wiki/Fuzzball_(string_theory)
- roywiggins 8y ago
  I tend to agree with you. Are mathematical singularities physical? We just don't know. I think probably not on philosophical grounds. But we can't peek inside an event horizon to find out, and these event horizons seem to exist, so whatever the structure of the insides of them are, they're still black holes.
TeMPOraL 8y ago
Then there's this video ESO's Very Large Telescope shot[0], of stars orbiting something that's a) very massive, and b) invisible. Does that constitute a direct observation of a black hole? -- [0] - https://www.youtube.com/watch?v=TF8THY5spmo https://www.youtube.com/watch?v=TF8THY5spmo
oldandtired 8y ago
No. Incorrect. Wildly inaccurate. We have made certain observations that are assumed to be the result of matter falling into a "Black Hole". We do not have any observations that show us this as a fact. Read the observational material very carefully. Go back over the last few decades and see how many times it is declared "we have seen x for the first time", where x is the is the same entity each time, in this particlualr case "Black Holes". Men (women, children) want to believe that they have a certain handle on the truth and reality. What is very unpleasant to most is not having that certainty. This applies to all people across the board and even more so to those whose expertise is dependent on their being right. Many scientists are in this category. It is often difficult to sit in the place of recognising that we just don't know. We have some ideas which, on the evidence, give a handle to investigate further, but we should understand that our understanding can be turned on its head. The evidence for the existence of something is there, yes. But, is it a "Black Hole" of the theory presented, hmmm, that is unknown and for the time being, unknowable. As we cannot get out there and actually do the appropriate experiments to test this. We can only do remote observations and these can be easily misinterpreted. >>Nobody except cranks or extreme contrarians seriously disputes the theory these days. The problem here with this view is that it has been "cranks" and "extreme contrarians" who have brought about the biggest changes in science. There are Nobel Prize winners amongst them. All views about the nature of our universe should have those who dispute it. This should spur on our investigations into the nature of the universe. If we are unable to handle someone disputing our models and theories of the universe, then what are we doing? We are not serious about expanding our knowledge, we are serious about our reputations and being right. The biggest problem for science today is that people don't trust it because it keeps getting things wrong, yet all the while saying that it is the only source of truth. Science is one of a group of tools we can and should use to investigate the universe around. It has its limitations as does all the other tools we have and we need to recognise that though this tool is helpful in understanding, it is not the tool that gives us the truth.
- InclinedPlane 8y ago
  If you're trying to get me to take you seriously you've failed. Do you think that condescension mingled with evidence free assertions are the way to support an argument? Is that science in your eyes?

roywiggins 8y ago

I believe the argument is that event horizons exist but inside is not a singularity, but an eternally collapsing mass of the original star. From the point of view of the star, it does collapse all the way, but from our point of view that final singularity collapse is in the indefinite future. https://en.m.wikipedia.org/wiki/Magnetospheric_eternally_collapsing_object https://en.m.wikipedia.org/wiki/Magnetospheric_eternally_col...

roywiggins 8y ago
Update: I am mistaken. The classic GR black hole behaves this way. MECOs supposedly never fully collapse into a singularity, even for infalling observers. That's the difference. I rather think we'd have noticed the difference from LIGO gravitational wave measurements of BH mergers, but maybe not?

perl4ever 8y ago

From your point of view, if so-called black holes are "fuzzballs"[1] is that a vindication or a refutation of the existence of black holes? Without a deep understanding of physics, I have the general attitude that infinities must be a mathematical error, and therefore something must stop black holes from collapsing totally, but whether they "exist" is only a matter of definitions. [1]https://en.wikipedia.org/wiki/Fuzzball_(string_theory) https://en.wikipedia.org/wiki/Fuzzball_(string_theory)

roywiggins 8y ago
I tend to agree with you. Are mathematical singularities physical? We just don't know. I think probably not on philosophical grounds. But we can't peek inside an event horizon to find out, and these event horizons seem to exist, so whatever the structure of the insides of them are, they're still black holes.

TeMPOraL 8y ago

Then there's this video ESO's Very Large Telescope shot[0], of stars orbiting something that's a) very massive, and b) invisible. Does that constitute a direct observation of a black hole? -- [0] - https://www.youtube.com/watch?v=TF8THY5spmo https://www.youtube.com/watch?v=TF8THY5spmo

oldandtired 8y ago

No. Incorrect. Wildly inaccurate. We have made certain observations that are assumed to be the result of matter falling into a "Black Hole". We do not have any observations that show us this as a fact. Read the observational material very carefully. Go back over the last few decades and see how many times it is declared "we have seen x for the first time", where x is the is the same entity each time, in this particlualr case "Black Holes". Men (women, children) want to believe that they have a certain handle on the truth and reality. What is very unpleasant to most is not having that certainty. This applies to all people across the board and even more so to those whose expertise is dependent on their being right. Many scientists are in this category. It is often difficult to sit in the place of recognising that we just don't know. We have some ideas which, on the evidence, give a handle to investigate further, but we should understand that our understanding can be turned on its head. The evidence for the existence of something is there, yes. But, is it a "Black Hole" of the theory presented, hmmm, that is unknown and for the time being, unknowable. As we cannot get out there and actually do the appropriate experiments to test this. We can only do remote observations and these can be easily misinterpreted. >>Nobody except cranks or extreme contrarians seriously disputes the theory these days. The problem here with this view is that it has been "cranks" and "extreme contrarians" who have brought about the biggest changes in science. There are Nobel Prize winners amongst them. All views about the nature of our universe should have those who dispute it. This should spur on our investigations into the nature of the universe. If we are unable to handle someone disputing our models and theories of the universe, then what are we doing? We are not serious about expanding our knowledge, we are serious about our reputations and being right. The biggest problem for science today is that people don't trust it because it keeps getting things wrong, yet all the while saying that it is the only source of truth. Science is one of a group of tools we can and should use to investigate the universe around. It has its limitations as does all the other tools we have and we need to recognise that though this tool is helpful in understanding, it is not the tool that gives us the truth.

InclinedPlane 8y ago
If you're trying to get me to take you seriously you've failed. Do you think that condescension mingled with evidence free assertions are the way to support an argument? Is that science in your eyes?