Hopefully. In fact one might use this as a rubric, that in order to be considered good enough, a quantum theory of gravity ought to be able to at least explain this problem. But alas, we do not yet have any quantum theory of gravity.
It’s also worth mentioning, by the way, that even in fully classical (i.e., non-quantum) GR, the event horizon is still not something that’s locally definable. The event horizon is defined as the point beyond which light cannot escape to infinity, which means that if you’re anywhere short of infinity, you can’t actually tell. In the most straightforward cases there will be an apparent horizon which is locally definable, and which coincides with the real horizon, but not all cases are so straightforward, and you can’t necessarily tell if you’re in one of the non-straightforward cases. It’s even possible to cross over the event horizon of a black hole under circumstances where no possible measurement you could even conceivably perform would even tell you of the hole’s existence.
And I believe this means that even an ordinary black hole, if it is evaporating, does not have a proper ‘event horizon’ defined like this, no?
In any case, what Hawking says is not nearly as revolutionary as some have claimed (and of course poo-pooing for flip-flopping (how’s that for technical language?) on the issue is missing the point entirely—opinions evolve, in fact, they must evolve for science to progress). There are black holes, for all intents and purposes, though in detail, they may behave differently from how we thought they did (but we already knew they would, in some way or another).
Does Hawking actually say “There are no Black Holes” or is that phrase the work of a Nature magazine media klutz?
Wasn’t whoever used the phrase here being seriously, and I would say irresponsibly misleading? No scientists suggest that BH do not exist, do they? It is only that BH do not, after all, have the attribute of an event horizon from which absolutely nothing can escape, isn’t it?
Many of you have probably noticed that the Anti-Science Neanderthal Right Wing has taken the story, with Michele Bachman and other real morons gleefully ridiculing science and scientists, and launching guilt-by-association diatribes against evolution and climate change. I hope scientists and the scientific press learn from this blunder, and will in the future avoid unnecessarily providing ammo to the stupidest elements of politics and society.
And another thing- Hawking, at 70, is way past the age where scientists can be counted on to make significant contribution. It is time for him to retire, or, to put it less politely, it is time for him to shut the hell up, and let someone else get the credit for exposing his errors.
Yes, I know Einstein also used the phrase “my biggest mistake” (in regard to the cosmological constant). However, for that time’s state of scientific development Einstein had the right answer originally but changed it, whereas Hawking had the wrong answer to begin with. Also, Hawking is not close to being an Einstein-caliber scientist, and it is too bad his reputation has always been inflated so far beyond his endowments, because then he would not have gotten the recent headlines which have led to the ongoing fiasco now being witnessed.
So…meh. Given how little we know about black holes and the regions where GR and QM interact reimagining “clothes” on a singularity seems like an innocuous update in a definition.
As to what the likes of Bachmann and company think, I think I speak for most people when I say “They can?”
There are at least four typos in the quotation above- Hawking’s secretary and his editor did a damn poor job of it.
However, I think I can reasonably interpret it to mean that, yes, there are still Black Holes, only that they must be redefined somewhat.
But the part of the basis of this brouhaha is that the original definition was in Hawking’s opinion his biggest mistake. And if Hawking says something is the biggest, well then by golly it must be BIG.
The unfortunate political reality is that the Bachmans of the United States have a legislative majority in most states, and a half a majority in Congress, so your “most people” seriously understates the danger they pose, doesn’t it? And even if they were not as strong it would make no sense to give them ammo like this stupid “there are no Black Holes” meme is doing as we speak.
I saw that. The story seemed to have been cited as real elsewhere.
The potential for mischief is there even if the story is satire, though. Also, I would think Bachman will have to treat us to a press release of some sort. It will be interesting to see what she says.
Is it still expected that the General Relativity model will be an excellent approximation for astronomical black holes, or do any of the models including Quantum Mechanics predict that macroscopic black holes will be radically different in an observable way?
To reiterate what I said in post #13, the event horizon as the defining feature of a black hole is textbook stuff and I believe this definition was first explicitly made by Hawking and Ellis in fact in their textbook.
However even where this definition appears in textbooks the very exacting and slightly unsatisfactory nature of this definition is pointed out (e.g. Wald) and there certainly are other definitions of black holes.
Or in other words its clear that where the “there are no black holes” comes from, but even if we take Hawking’s paper at face value , I’m sure we’re still going to carry on calling these objects black holes just as he does in the paper.
Yes, I mean there are certainly big differences in the spacetime structure, but from a practical observational pov, then you would still expect the Schwarzschild/Kerr solutions to be excellent approximations.
No, actually the paper simply wouldn’t copy across cleanly.
Right, even if you read the Nature article it says “Most physicists foolhardy enough to write a paper claiming that “there are no black holes” —* at least not in the sense we usually imagine*” actually says that as well - emphasis is mine.
I’m not exactly sure what this is about. Hawking’s paper from the '70s was about information and he’s graciously conceded a bet on the paradox to Preskill. If you have a cite for what you’re referring to, this I’d appreciate it.
Look just because the US Right is held hostage to gibbering morons is no reason the rest of us have to give them the time of day.
WheatCat, political commentary of this kind is not appropriate for General Questions. I would suggest you dial back the tone of your remarks in general. If you want to rant about the right wing, or about Hawking, open a Pit thread. No warning issued.
Wow, people are blowing this thing way out of the water. This is basically a three-page writeup of a ten minute talk delivered via Skype at the Kavli institute’s ‘fuzz or fire’-workshop, it’s not through any sort of peer review yet, and I’m not sure Hawking even will seek publication—something like this is done sometimes just to have a better way of citing a talk. It’s not the science god’s high prophet laying down the law, nor is it even majorly inconsistent with what Hawking has said in the past; and to suggest that he should ‘retire’ because of something like this is simply ridiculous—it’s clearly a worthwhile (though perhaps not outstanding) contribution to the current debate, which, again, is about a very much unsettled foundational issue with ultimately little real-world relevance.
And it’s not like the controversy about the black hole information issue has ever really settled down completely only to now be stirred up again; while Hawking conceded the bet, Kip Thorne, for instance, did not, and other scientists like Bill Unruh (and maybe also Wald?) have in the wake of the recent developments again been arguing for information loss mostly to save the equivalence principle.