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Post by mrsonde on Mar 21, 2018 14:53:27 GMT 1
Not quite. We observe a consistent-ish behaviour of mesoscopic objects which we can describe by a single equation that holds for most practical purposes to such a degree of accuracy and predictability that, for reasons of history and in the absence of a better word, we call it a law. Then we find exceptions at the microscopic and macroscopic levels: atoms don't collapse under self-gravitation and rotating galaxies don't disintegrate, but neutron stars and black holes seem to behave like classical "billiard ball" physics. The puzzle about atoms not collapsing isn't generated by gravity but electric charge. I confess I don't follow the great mystery about rotating galaxies at all - supposedly there should be too much angular momentum for the galaxy as a whole to hold together given its inadequate constraining mass. You say you're an expert on angular momentum - what are the equations that lead to that conclusion? The ones I was taught are applied on a particulate level - in this case, each star. What any other star might be doing isn't part of the calculation at all, is it? They're summed afterwards, not before, aren't they? And as I've posted here before, if it's such a mystery how spiral galaxies hold together, why isn't there the same mystery about Catherine Wheels, anti-cyclones, or any other classical vortex? Also, not to carp, but the whole corpus of Hawking's work is how black holes don't behave classically.
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Post by mrsonde on Mar 21, 2018 15:07:57 GMT 1
Not quite. We observe a consistent-ish behaviour of mesoscopic objects which we can describe by a single equation that holds for most practical purposes to such a degree of accuracy and predictability that, for reasons of history and in the absence of a better word, we call it a law. Then we find exceptions at the microscopic and macroscopic levels: atoms don't collapse under self-gravitation and rotating galaxies don't disintegrate, but neutron stars and black holes seem to behave like classical "billiard ball" physics. Faced with a universe that doesn't quite obey the laws we thought we had imposed on it, those with the intellectual strength and honesty to be scientists say "that's interesting" whilst the feebleminded say "god moves in a mysterious way". Can you understand/explain what Hawking meant when he said "Because there is a law such as gravity, the universe can and will create itself from nothing"? If that's a direct quote, he's adumbrated an extremely complicated theoretical attempt at amalgamating what we know about gravity with something far more questionable, that mess of internally contradictory equations, ad hoc approximations, and unexplicated presumptions generally called " quantum theory". There's nothing in General Relativity - the last word on what we know about gravity, still - that would lead to anything like his conclusion. How he gets there is in the tiny unobservable bits of space-time and action below the Planck limit where particles can supposedly self-generate from a theoretical frothing virtual sea of constant energetic fluctuation, from nothing to almost something, from almost something to something actual - supposedly allowed by the fuzzy indeterminacy of the quantum theory probability equations. This frothing virtual sea, for some reason, he does not consider asking: why is that there, rather than the "nothing" I'm claiming to be talking about? He spins this facile idea a lot further, I'm afraid, thanks to his apparent unquestioning acceptance of a highly dubious - at any rate, unconfirmed and as far as I can make out unconfirmable (unfalsifiable) - "theory" (somewhat too complimentary a term, I think) called M-theory (itself a fanciful imaginative what-if spinning-out of a much larger spaghetti of pseudo-scientific fancies called string theory - or so he apparently seems to think!) In any event - nothing to do with "gravity", really.
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Post by fascinating on Mar 21, 2018 20:16:24 GMT 1
Thank you. The relevant paragraph, as quoted by the Times said "Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going." See www.wired.co.uk/article/hawking-god. I see that you are highly doubtful about his view and I don't blame you. What I would like to know is, does it make any sense at all? Saying that something can create itself from nothing surely makes no sense at all? A thing cannot create itself, surely. But is he saying that the universe arose out of this basic thing called gravity, which existed before there was time, space, matter or energy?
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Post by alancalverd on Mar 21, 2018 20:32:11 GMT 1
It's all in "Black holes and baby universes" IIRC. Hawking made some attempt to reconcile Hoyle's continuous creation with what looks like evidence of a big bang, using only the presumption that the law of gravitation is universal. His explanation is a lot neater than I can produce here, but AFAIK the key phenomenon of a self-annihilating black hole hasn't actually been observed..
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Post by mrsonde on Mar 22, 2018 0:53:15 GMT 1
Thank you. The relevant paragraph, as quoted by the Times said "Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going." See www.wired.co.uk/article/hawking-god. Who knows what he might have meant by "a law such as gravity." The only recognised "law of gravity" would be Newton's, or, if one wanted to be generously flexible, Einstein's GR formulation. Neither had anything to say or even imply about the universe thus being able "to create itself from nothing". I am indeed. As it stands it's merely an off-the-cuff opinion, which he gave no rational support for whatsoever. We're all entitled to such unsupported opinions, I suppose; what I find objectionable is his pretence that scientific discoveries, or even theories, supported his belief. He does this over and over, it's not just a one-off slip of the cursor, or lazy reporting - he wrote a whole book promulgating this view. No - well, it makes some sort of sense, but it is not a scientific theory; nor is it supported at all by any scientific evidence. But don't take my word for it: many people have pointed these facts out - philosophers, physicists, mathematicians. Probably the most devastating if polite critique came from Roger Penrose, his long-standing collaborator - and by far the superior scientist, in terms of his accomplishments at least (not to mention his reasoning powers, as displayed in his books on these matters, which are classics. Not that I can follow - but as I've said, that wasn't what Hawking argued in any case. He just called it "nothing" for some reason - well, he did so to make these headline-grabbing pronouncements about atheism, obviously. Why he felt such a need - I have no idea. He's saying that the Big Bang was, before it exploded, a Black Hole. Given the virtual sea hypothetically "within" such an object, eventually particles will probabilistically pop into existence, and half of such creations will be emitted - this goes back to his mathematical prediction and subsequent confirmation of "Hawking radiation" from such objects. So - another motivation for all this fanciful speculation is to draw attention to the work he became famous for - he's saying, take note, you thought my discovery was a little footnote in the annals of science, but actually it meant the final funeral rites for God - you've got me to thank for that, I thankee.
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Post by mrsonde on Mar 22, 2018 1:01:15 GMT 1
It's all in "Black holes and baby universes" IIRC. Hawking made some attempt to reconcile Hoyle's continuous creation with what looks like evidence of a big bang, using only the presumption that the law of gravitation is universal. His explanation is a lot neater than I can produce here, but AFAIK the key phenomenon of a self-annihilating black hole hasn't actually been observed.. He may have tried such a tactic previously, that one passed me by. In his last book he relies on one of the fifty or so versions of String Theory to start creation off, then crucially on the Multiverse Theory - a very fanciful form of the Anthropic Principle, which he gives only the most cursory of defences for. That is, given the start, eventually the universe we observe, with all its astounding necessary coincidental harmonies, must eventually arise - else there's be nothing to observe and nothing to observe it. Scientifically, the whole thing is drivel - nothing more than very poor SciFi. Philosophically, it's garbage.
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Post by fascinating on Mar 22, 2018 8:24:29 GMT 1
Thank you, I did think it was garbage. I would have been understanding if he had said those things in an interview as a kind of rhetorical flourish (or attempt to send the interviewer away happy so he didn't have to go through the enormous bother, considering his difficulties, of a full explanation) but this was in a book, so it's hard to forgive.
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Post by mrsonde on Mar 25, 2018 17:40:22 GMT 1
Thank you, I did think it was garbage. I would have been understanding if he had said those things in an interview as a kind of rhetorical flourish (or attempt to send the interviewer away happy so he didn't have to go through the enormous bother, considering his difficulties, of a full explanation) but this was in a book, so it's hard to forgive. Yes, I agree. It doesn't mean what he believed isn't true, mind you. Just that his arguments for it were hopeless. Personally, it doesn't bother me if it is true - it's nothing to do with the question of whether "God" exists, as far as I can see. If it does exist, it's surely a natural phenonemon! This is the basic problem with the Anthropic Principle, isn't it? If this is the only universe that could exist, in all its amazing improbability, then why isn't it the case that therefore God must exist for it to be also? No possible answer to that whatsoever - which just shows what illogical nonsense the Anthropic Principle is, imo.
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