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Black Holes Don't Exist???
OldSoldier writes: "Here is an article
that was first published in the April issue of a small SciFi magazine called
Analog. The author, John
Cramer, is one of two columnists for the Alternate
View column and his columns are very thoughtful and more grounded in
science than most. In particular, this article states that there is a small
but growing group of physicists who have come up with an alternate formulation
to Einstein's General Relativity equations that do two rather stunning things.
One is that they allow super massive non-black hole objects and the other
is that they are able to be quantized. If you like this article, I suggest
you go to his index and
read some of his previous articles."
Hasn't the recent Microsoft debacle taught people anything? You can't post a copyrighted work in it's entirity without permission, even if it is slashdoted. That goes way beyond the provisions for fair use, and only encourages people to start reducing the simplicity of accessing information.
Do you want slashdot to become like those theiving commies at FreeRepublic?
I have been following physics for quite some time and have seen the difficulty in trying to formulate a Quantum Theory of gravity. I think that we will find--very soon--the bridge that crosses the gap between General Relativity and Quantum Mechanics.
One of the more promising theories, as of late, is called M-Theory. It is able to unify all five "types" of super strings. This view of sub-nuclear physics also attempts to answer a lot of questions about cosmology. This would include the actual number of dimensions in space-time and the actual structure of universe, itself.
The problem with the original Super String Theory was that it lacked "testable" predictions. The energies required to probe to that level were in the range of around 10^16 TeV. However, there has been some recent speculation that some of the extra dimensions could be larger than the Planck length (10^-34 m). Physicists were hoping to catch a glimpse at these higher dimensions by observing the effects of gravity at close range.
Some believe that gravity may propagate through more than three spacial dimensions, since it is so hard to unify with all the other fundemental forces. If this is the case, then gravity will fall off at a rate greater than the square of the distance. This would also mean that super-unification would probably happen at a lower energy scale (in the TeV range), as opposed to the dreaded 10^16 TeV range.
First of all, with the word "theorem." My area of expertise is mathematics, and in math a theorem is any statement which can be shown to be a logical consequence of axioms assumed at the outset. Now, in math we use a bunch of set theory axioms as the foundation of theorems, and in fact (strange as it may seem) all theorems of mathematics can be formulated as statements in set theory and proven using these axioms.
Physicists have also been known on occasion to use the word "theorem" (Noether's theorem from mechanics, Hawkings' theorem on existence of singularities in GR), but physicists also restrict themselves to the strict definition of theorem--theorems are always logical derivations from basic assumptions (which in physics take the form of hypotheses).
Secondly, I will agree that scientists have an underlying assumption that the world works in a consistent, predictable manner. However, I personally consider this assumption to be an hypothesis, i.e. just as falsifiable as any other proper scientific theory. This hypothesis has a major prediction--roughly, that natural processes proceed the same everywhere and at all times. The existence of such wonderfully verified theories as evolution, quantum theory, and yes, GR, is testament to how remarkable this theory is.
Anyway, my point is that GR is a theory, and placing it as an axiom one can produce theorems like those of Hawking. GR, however, is perfectly falsifiable, and so if this alternate theory turns out to predict phenomena better than GR, eventually it will inherit acceptance. This doesn't, however, mean that physicists working in GR right now will lay down immediately. Partisanship is an important part of the scientific process--without a healthy debate about theories, ideas get stale. The result is that scientists end up adopting the theory which has been least falsified. And I have every confidence that if GR is shown to be substantially more inconsistent with observation than this new theory, then Hawking and everyone else will accept it.
BUT, this does not mean that you can just go around claiming that scientists who have no alternate theory for, say, evolution are necessarily not open-minded. In my opinion, comparing evolution and quantum theory to GR suggests a severe lack of understanding. Evolution has been around for 150 years and itself has been a continuously evolving theory, changing as more information is uncovered. Somehow, however, the basic idea (that species arise from differential change within other species) has stood the test of time. Quantum Theory is very similar--the Standard Model is one of the best predictive models in science, and has been ruthlessly tested in particle accelerators for half a century. GR, on the other hand, is one generalization of special relativity (which has been heavily verified on a microscopic level), and its interesting implications are all in a high-gravity context, about which we have very little direct information. As this new theory agrees with GR for low-gravity environs (like our own), it seems to be a reasonable alternate theory. Whenever you have an area of science where data is not in much abundance, multiple theories will crop up. But usually, large bodies of evidence (like that for quantum theory and evolution) will leave space for only one major theory.
Sorry for the rant. I just get irate when people try to argue about science without the proper context.
Aren't you dead?
... think of all the SciFi material we have to rewrite now!!!
it's in my head
The advocates of the Yilmaz theory list the following additional advantages (not discussed further here) of the Yilmaz theory over conventional GR: (1) it predicts a definite stress-energy tensor while GR does not; (2) it provides exact solutions for gravity waves of arbitrary field strength while GR does not; (3) it has a true Lagrangian while GR does not; (4) it implies Einstein's equivalence principle, while GR must take equivalence as a separate assumption; (5) it is quantizable while GR is not.
PS: When I read the article, their counter was at 340. Next refresh displayed all zeroes ... poor website.
it's in my head
This article makes some good points, but some fairly invalid ones. Maybe it's just the way he explains.
Mathematics doesn't "blow up" at singularities -- it's merely a place where every known equation we have that deals with GR gives us an answer of infinity. Now, this is a problem that's occured in mathematics for centuries, and people have solved these problems for centuries (L'Hopital's rule, for one)
Well, if Black Holes don't exist, we're sorta screwed. Not necessarily screwed, but it does flush about 60 years of decent cosmological physics down the drain. I guess that's happened before.
It comes down to who you want to believe, I suppose. Neither side of this argument has barely any evidence of what they're claiming, so, what sounds better to you?
Before you bash Hawking (Yes, there's a 'g' on his name) maybe you should get to know the guy first. He's a brilliant, charismatic, humorous guy, and he's perfectly ready to admit he's wrong when shown to be so by evidence. Hawking has said some stupid things (stupid relative to the level of brilliant science he usually produces) in his life, and he has been quick to throw out erroneous work when he was shown to be wrong.
People like Hawking, if confronted with a suitable replacement for GR (not necessarilly saying this is suitable, obviously there were no mathematics in this pop article), will jump on-board the new theory, excited at the chance to learn and demonstrate new things about existence. It's the pursuit of truth that drives them, not the glory.
Maybe you could learn a thing or two from them about pursuit of truth... It has nothing to do with what you believe to be true, it has to do with what you can determine to be true. Belief can still exist, it isn't a problem, but if you believe something that contradicts what is in front of your face, then maybe what you believe needs minor adjustment.
Most non-physicists don't care about what goes on under the event horizon, and would be perfectly happy to call anything a black hole that is heavy enough to have an escape velocity greater than the speed of light at some height above its surface. You still couldn't see them unless something was falling in, they'd still have a powerful lensing effect on light, they'd still gobble up stars and planets, you still would never want to fall into one, and things would still be seriously wierd right near the "event horizon" (meaning, in this case, distance beyond which even light cannot escape).
Really, they just mean "no singularities," and since singularities are supposed to hide behind event horizons, they aren't really very interesting to the layman. I suppose it also means "no small black holes" (which would evaporate so quickly you wouldn't notice them anyway, except perhaps as a hiccup in the massive blast you'd need to create them with), since without singularities you'd need to pile up enough mass to make an escape velocity over the speed of light beyond the surface of the pile.
OTOH, maybe we don't need singularities for singularity-like effects. Maybe matter will compress beyond composite baryon structures more easily than we think, and be stable enough to be interesting. Quantum mechanics is still pretty hairy, and I don't think we know as much as we think we know.
Interesting, but people have been trying to "extend" GR for years. Prof Yilmaz is probably not the only one around. Here is a summary of why GR is so troublesome to many people : (a) It is not a gauge theory. Which is irritating to physicists because the rest of the other forces (weak, strong, electromagnetism) is. Basically a gauge theory takes some form of "particles/fields" (field is the correct word, but people seem to be familiar with particle more), impose some "geometric" constraint on it (i.e. the curvature thing Cramer is talking about), and Walla! You get the equations of motions, eg. the Maxwell equations for EM etc.. The point is that all the other forces are DERIVABLE from some consideration, which led physicists to believe ALL forces must be a gauge theory. But GR is not. Now in a Gauge theory, one can derive the Stress-Energy tensor by using Noether's Theorem. Why is this S-E thing so crucial? Well because the S-E tensor basically says Energy/Momentum/What-have-you is conserved! Yes, another surprise : Conservation of Energy is DERIVABLE from a gauge theory. It is not some "fuzzy concept" we impose arbitrarily. But in GR, we can't do that. So we can't impose local conservation of energy. People are disturbed by this... That's why physicists wanted nice "gauge theories" . Now, having said all that, it is conceivable to "extend" GR, by basically adding more "terms" in the equations, take make GR a gauge theory. This is what probably Yilmaz has done (i've not seen his papers, but I will bet my library on this). OK, the get nice gauge theories and such....BUT why add more terms?? This question is begged to be asked. They say : so it's a nice Gauge Theory! But we say : but that's cheating! The solution : make observations. The observations : nah....Black Holes probably exist. (b) GR is not renormalizable. "Renormalization" is just a big term to indicate that we can "get rid of the infinities" by some trick. Now Renormalization is a big thing to physicists : it makes equations nice and "well behaved" (literally). Physicists/Mathematicians know how to renormalize Gauge Theories (a few Nobels have been awarded for this great breakthrough, Feynman/Schwinger/Tomonoga for QED, Wilson for renormalizable gauge theories, d'hooft and Veltman for non-abelian gauge theories). But GR is NOT a Gauge theory! And people still don't know how to renormalize it. But instead of screaming "no!", physicists embraced the resulting Infinities as "hey that's cool! Look Ma, a Black Hole!". Why? I don't know, probably historical. But IT'S BLOODY HARD TO RENORMALIZE A NON-GAUGE THEORY!!!!! (c) It is not Quantizable. Now, we know how to quantize a renormalizable gauge theory (see : I cleverly organized this article such that everything falls into place :)). But GR is NOT a renormalizable gauge theory! So we don't know how to quantize it! Thus we are in a time in the history of Science that we are stuck. Unless we do things like Yilmaz, by arbitrarily adding terms to the equations (for those physicists out there : we add extra couplings to the Lagrangian), we are left with either accepting that GR is just DIFFERENT from the rest of the world, OR, that we just have an incomplete theory. Physicists, of course, to protect their jobs and grants, say "We have an INCOMPLETE THEORY! GIve us more money!" The current "hot" thing is Superstring. A marvellous piece of beautiful mathematical theory that "may" unify GR and the rest (the so call Super Unified Theory, as opposed to Grand Unified Theory w/o GR). The only problem is, as Cramer said, "it's under construction". He did not mention something more sinister : "Superstrings predict crazy things!!!!" Yeah, like 10^16 GeV particles (an accelerator the size of the Milky Way is needed to make such particles). So SUPERSTRINGS has NO experimental evidence. Here thus, is the current situation in Physics. So, as a wanna-be theorist, I implore you, Slashdotters to : GIVE US MORE MONEY ! WE HAVE AN INCOMPLETE THEORY!
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