Discussion in 'Physics & Math' started by RJBeery, Jan 24, 2014.
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Black holes do exist. There are things out there that are very very massive, and very very small. And we can't see them. Because they are... black.
That's not to say that point singularities exist. See Kevin Brown's Formation and Growth of Black Holes where he refers to two different interpretations of GR, one where the point singularity doesn't exist. He doesn't favour it, but he does refer to it:
"Incidentally, I should probably qualify my dismissal of the "frozen star" interpretation, because there's a sense in which it's valid, or at least defensible. 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".
It seems that Hawking is echoing this another way, which I think is OK. There's always room for a different interpretation. But I was disapoointed that there was no mention of Friedwardt Winterberg's original firewall. See wiki:
"In another article these same authors claimed similar concepts have been proposed in the past. Of these Winterberg's proposal has priority.
In a nutshell: the coordinate speed of light varies in a non-inertial reference frame. If you drop an electron into a black hole it falls faster and faster. Meanwhile the coordinate speed of light is getting lower and lower. The electron cannot fall faster than the local speed of light. It gets destroyed. Hence gamma-ray bursters. If Winterberg is right then black holes still exist, and so do event horizons. But the AMPS firewall doesn't exist, and nor does Hawking radiation.
I've held that neither singularities nor event horizons exist...to considerable resistance.
A giant gas cloud is on a collision course with our galaxy's black hole. You can watch it in real time, if you'd like.
Black hole's 'big meal' could spark fireworks
RJ: the event horizon is said to be a singularity of sorts. Most people will tell you it's a mere artefact, because most people favour the "other" interpretation where the singularity is a point singularity. I'm happy with the event horizon and the black hole, but not the point singularity.
Thanks, interesting event coming up. Did you see the previous threads on the stars orbiting about the central black hole?
You're conflating two very different things here. Resistance to arguments you have given against the existence of black holes is not the same thing as resistance to the conclusion.
(Extreme) example: special relativity has a long history of being attacked by anti-relativity crackpots. Suppose it's one day found that special relativity is incorrect in some future high energy particle physics experiment (something that's entirely possible, and there are even reasons one might hope for this). Would that mean that all these anti-relativity crackpots were really misunderstood geniuses who saw what the mainstream physics community couldn't see all along?
Look at Trooper's response; it isn't atypical. A common rebuttal is to simply point at black splotches in the sky, NOT address any of my arguments directly.
How 'bout this, RJ?
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RJ, I think the headlined title of the Nature article, takes Hawking out of context. The quote in the title was extracted from the following sentence in his paper,
"The absence of event horizons mean that there are no black holes - in the sense of regimes from which light can’t escape to infinity."
Even the sentence as a whole, when read apart from the paper, seems to present the potential for misunderstanding and again an out of context interpretation.
The paper on the whole does not seem to me to be questioning the existence of the black hole, so much as it questions the character or nature . . . and its affect on in falling matter, of what we have called the event horizon... And Hawking's paper is essentially a reply to an earlier paper (though not a direct reply), also mentioned in the article...
Trooper, good informative Link! I first heard of the earlier Thorne/Hawking bet in the early 1980's - I never knew of the actual outcome until reading the Page at your supplied Link, so...thank you.
I agree it could be a contextual thing but...if we start redefining black holes so they don't contain an event horizon I call it a semantic dodge.
Er, yes, there are many people who post in your threads who a) don't understand general relativity very well or even at all, and/or b) are not effective debaters and post responses that miss the point or even amount to knee-jerk reactions. That doesn't vindicate you.
Some relevant points from an Interesting article.......
"A full explanation of the process, the physicist admits, would require a theory that successfully merges gravity with the other fundamental forces of nature. But that is a goal that has eluded physicists for nearly a century. “The correct treatment,” Hawking says, “remains a mystery.”
" He titled it, whimsically, 'Information preservation and weather forecasting for black holes', and it has yet to pass peer review."
“The picture Hawking gives sounds reasonable,” says Don Page, a physicist and expert on black holes at the University of Alberta in Edmonton, Canada, who collaborated with Hawking in the 1970s. “You could say that it is radical to propose there’s no event horizon. But these are highly quantum conditions, and there’s ambiguity about what space-time even is, let alone whether there is a definite region that can be marked as an event horizon.”
The above quotes says it all, and coupled with the sensationalist nature of the head line, makes for an Interesting article.
GR BH's certainly exist, the exact details may still be questionable, but if they didn't exist, cosmology would have an even larger problem in explaining the effects that are observed and put down to BHs.
It would seem that the "Interesting article......." you are referring to, is the article that is Linked in the OP :
According to this, from : http://www.sciforums.com/announcement.php?f=33
You possibly or probably should have included the Link or at least more acknowledgement of the source than you gave. i.e. attention to detail and all that...
I just noticed you'd started a similar thread on PhysicsForums. The consensus from the first few posts seems to be the same as the one I hinted at here:
Arguments you've made regarding the existence or logical consistency of black holes, in the context of classical general relativity, were wrong/unfounded/unconvincing etc.
Nobody, including you, can claim to know with any real conviction whether black holes exist according to some hypothetical theory of quantum gravity that we don't have at the moment.
Nobody, including you, can claim to know with any real conviction whether black holes exist in reality.
No need for it. Any logical person would see that I was quoting from the article which was already given in the OP.
Separate names with a comma.