Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: annie123 on 25/09/2014 20:47:56
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Laura Mersini Houghton says she has evidence that black holes don't exist. Does anyone out there have views about this? Surely, if true, and she says she has evidence(can you check it anyone?) then a lot of people might lose tenure . . . I wonder what SHawking has to say about this.
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Quote from media this week
Carolina’s Laura Mersini-Houghton shows that black holes do not exist
The term black hole is entrenched in the English language. Can we let it go?
(Chapel Hill, N.C. – Sept. 23, 2014) Black holes have long captured the public imagination and been the subject of popular culture, from Star Trek to Hollywood. They are the ultimate unknown – the blackest and most dense objects in the universe that do not even let light escape. And as if they weren’t bizarre enough to begin with, now add this to the mix: they don’t exist.
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She certainly has a different take on most of cosmology, but proof of nonexistence demands considerable rigour.
I guess the simple question is whether we have any evidence of their existence. http://www.damtp.cam.ac.uk/research/gr/public/bh_obsv.html suggests we do.
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Laura Mersini Houghton says she has evidence that black holes don't exist. Does anyone out there have views about this? Surely, if true, and she says she has evidence(can you check it anyone?) then a lot of people might lose tenure . . . I wonder what SHawking has to say about this.
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Quote from media this week
Carolina’s Laura Mersini-Houghton shows that black holes do not exist
The term black hole is entrenched in the English language. Can we let it go?
(Chapel Hill, N.C. – Sept. 23, 2014) Black holes have long captured the public imagination and been the subject of popular culture, from Star Trek to Hollywood. They are the ultimate unknown – the blackest and most dense objects in the universe that do not even let light escape. And as if they weren’t bizarre enough to begin with, now add this to the mix: they don’t exist.
I read it and it's nonsense. Her error is in this statement
Before a black hole can form, the dying star swells one last time and then explodes. A singularity never forms and neither does an event horizon. The take home message of her work is clear: there is no such thing as a black hole.
This person is not an astrophysicist so she's not familiar with what happens to all kinds of dying stars. That's part of her mistake.
All that needs to happen is for matter to be confined within a finite region of space which is determined by the amount of mass of the material. The singularity is never observed from outside the black hole and can't be said to form by observers outside the black hole. And what this woman is neglecting is that black holes have been observed. She's also forgetting about the micro black holes formed at the creation of he big bang. She's also forgetting galactic black holes which don't form my dying stars.
See http://hubblesite.org/reference_desk/faq/answer.php.id=56&cat=exotic
If the core remaining after the supernova is very massive (more than 2.5 times the mass of the Sun), no known repulsive force inside a star can push back hard enough to prevent gravity from completely collapsing the core into a black hole.
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I doubt she's exactly right either. What if, at the point that the mass collapses to its event horizon, the magnetic flux is completely contained within the mass and it and the electric field swap places? What effect would such a change have on further collapse?
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I doubt she's exactly right either. What if, at the point that the mass collapses to its event horizon, the magnetic flux is completely contained within the mass and it and the electric field swap places? What effect would such a change have on further collapse?
After all. How are we to make that jive with this
http://www.nbcnews.com/science/space/surprise-giant-black-hole-discovered-dwarf-galaxy-n205896
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Laura Mersini Houghton says she has evidence that black holes don't exist. Does anyone out there have views about this?
Yes, I do. I've read about this, and IMHO there's some sensationalism going on, and some bad science too. One of the things I saw was "singularities don't exist therefore black holes don't exist". That just isn't true. In Oppenheimer's day the black hole was described as a frozen star. Light couldn't get out, but there was no point singularity. You can see a mention of this here (http://mathpages.com/rr/s7-02/7-02.htm):
"Remember that historically the two most common conceptual models for general relativity have been the "geometric interpretation" (as originally conceived by Einstein) and the "field interpretation" (patterned after the quantum field theories of the other fundamental interactions). These two views are operationally equivalent outside event horizons, but they tend to lead to different conceptions of the limit of gravitational collapse. According to the field interpretation, a clock runs increasingly slowly as it approaches the event horizon (due to the strength of the field), and the natural "limit" of this process is that the clock just asymptotically approaches "full stop" (i.e., running at a rate of zero) as it approaches the horizon. It continues to exist for the rest of time, but it's "frozen" due to the strength of the gravitational field. Within this conceptual framework there's nothing more to be said about the clock's existence. This leads to the "frozen star" conception of gravitational collapse. In contrast, according to the geometric interpretation..."
There are some very massive things out there, and they are black. Light can't get out. Whilst we can't see them directly, we can see that they're there, because of fast-moving stars and gamma-ray bursts etc. They're black holes. They exist.
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I agree, there are black holes and the Supermassive ones are magnetic hubs which will be found at the centre of all galaxies. But if matter particles get spun into then; they will be accelerated and fusioned to be re-emitted as light magnoflux energy at right angles to the spin of magnetic hub. That's what I think will happen?
CliveS
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Thanks for interesting replies.
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One thing she says that strikes a note of interest for me is:
“But the real motivation is that black holes are supposed to contain this singularity at the center, which is an incredibly exotic object. We can’t make sense of it with our physics.”
http://www.newsobserver.com/2014/09/30/4196212/unc-professor-pokes-theoretical.html#storylink=cpy
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black holes are formed when a massive star about 3 times the mass of our sun after supernova continues to contract and eventually to form black hole is gravity is so massive that the light whose velocity is 3*10^8m/s is also not close to its escape velocity which is much more.and therefore everything is sucked in to it just like the bath tub s hole or avaccum clener such that even light cannot escape from it and eventually it is invisible to see. we get to know about only from the x rays emitted by them whn it sucks something into it
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Gravity is an enigma, black holes suck and suck some more and never die eventually ulling in other black holes and everything.
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Not so long age the popular press were claiming that Stephen Hawking was denying the existence of black holes. It turned out that that was not exactly what he was saying.
Does anyone wonder if the Mersini-Houghton claims are being exaggerated; particularly in view of her having said:
“For the foreseeable future, it’s black holes.”
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She's also forgetting about the micro black holes formed at the creation of he big bang. She's also forgetting galactic black holes which don't form my dying stars.
I take your point, Pete, but from a brief skim through the article I had the impression she was talking about those black holes that apparently form as a result of the collapse of stars.
I'm sure there are plenty of things in her work that will merit criticism, but isn't that part of the point of publishing new ideas?
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One thing she says that strikes a note of interest for me is:
“But the real motivation is that black holes are supposed to contain this singularity at the center, which is an incredibly exotic object. We can’t make sense of it with our physics.”
http://www.newsobserver.com/2014/09/30/4196212/unc-professor-pokes-theoretical.html#storylink=cpy
See what I said above about Oppenheimer's original "frozen star" black hole. We don't need to make sense of the singularity at the centre. Instead we need to understand that black holes don't have to have a singularity in the centre. But that the lack of this doesn't mean that black holes don't exist.