This may come as a big surprise to some folks, but it is acknowledged that energy is not necessarily conserved in large-scale GR. I once thought of a paradox about that: Have either an infinite or closed hyperspherical, now-expanding universe. Let's say it is filled with a bunch of devices (acting like "galaxies" in cosmology) in a closed Cartesian array (
i.e. like integers in x, y, x.) Have them connected together (as "given") with elastic bands. Since the elastic forces on each object cancel out, the spatial standards of the universe and these objects can retreat from each other without being "held back." It's as if no bands, just gravity, right? But as this universe expands for awhile, the bands can accumulate whatever amount of elastic energy they can hold from W = (1/2)ks^2 (for some duration.) Note that if we want to avoid complications from elastic stress terms, we can imagine connecting cords used to turn generator rotors around as the cords unwind, etc.
(Similar recently posted in comments at
"Gravity is Entropy is Gravity is..." Sorry to Bee, I should have linked to here instead of spilling it there.)
This makes a problem of sorts about energy conservation. It may already be accepted that such things are possible, given the acknowledged issues with CoE in GR, but wouldn't you be surprised if this could work? It seems so much like that crank stuff that just is supposed to be possible.
Labels: general relativity, paradoxes
18 Comments:
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Neil, please be very, very careful whenever you write "free energy" that you're not labeled a crackpot.
Neil, how fast do you think the Universe is expanding? I may not be correct (so please check) but if I recall correctly it is on the order of 70.8 ± 1.6 (km/s)/Mpc, with Mpc = Megaparsecs, 1 Mpc = 3000 light-years. That's pretty small.
Also, where are you going with this? I think I understand but am not sure. Please re-read and expand on your ideas if you would. Assume the reader is an intelligent layman, not a Scientist.
Steven, thanks for warning me about being labeled a crackpot. I think that it's safe for me to bring up the subject in this context since word has gotten around (ironically, more among specialists than among laymen!) that energy is not necessarily conserved in GR. (However, note Bee's admonition about total stress-energy tensor being conserved. Now what!)
In any case, I present this (as I do my paradoxes in general) as a Socratic challenge, to force thinking and reassessing one's prejudices. After all, the result may be a solution that is still interesting, revealing, or challenging. A good paradox "succeeds" even if solved somehow.
Yes, the Universe is expanding very slowly but this is a theoretical matter of principle. The basic idea is, if elastic bands all attached in symmetrical directions then the net force on each object is zero. They aren't pulled one way or the other. So they should retreat from each other as they would w/o the bands. However, the bands build up "free" elastic energy.
Finally, I ask your and others' advice. Speaking of crackpottery, I worry that calling this blog "Tyrannogenius" makes me look too weird and cocky. I'm considering changing the name to "Paradoxer" or etc. Thoughts? And thanks for your continued support, since there are so many little blogs out there with "zero comments" over and over.
I like your new name better, yes, Tyrannogenius did make you look cocky, and I know you to be a passionate seeker of truth.
I'd like to know if you've written a paper on your Decoherence theory. It doesn't have to be at arXiv, it can be at viXra or whatever its called. Ask Jerome how it's done, he has one up.
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Steven, you prodded me at Bee's blog. I looked at your last comment here when it posted, then went careening around the Net and forgot. Yes I should write a paper but I'm less adept at getting QM optics written up right than I am at say, SRT dynamics. (I'm working on some in that area.) I'll consider viXra but worry that papers posted there are ignored or thought suspect. (LuMo recently ridiculed the site.) I'd prefer arXiv but need a sponsor and also edgy papers might be screened out even if good and relevant.
One thing, I'm still not sure just what DI advocates say actually happens in lieu of the mysterious but descriptively clearer Copenhagen. The old QM at least said there was a specific wave function distribution up to the moment a measurement happens, and then "poof" it's gone and replaced by the measurement results. But DI is couched in such infernal, post-modern psychobabble. They can't clearly say what they think happens because their "point" is based on confusion, doubletalk and circular reasoning. The whole thing falls apart if you have to explicitly model it (versus talking it abstractly) as e.g. a visual simulation in time and space - you can't show how the "lost" part of the superposition gets lost without tipping your hand or cheating. It just has to "vanish" or "into another world" at some point.
As for whether blogs are a good place to bring up scientific ideas and issues - I say yes. It gives the proposer a chance to see the idea hashed out, get advice and critique in advance of writing it up, etc.
PS Are you on Facebook? I've already got Bee, Stefan, Phil, Tommaso Dorigo and some others; would like to add more science types.
No I'm not on Facebook, I don't tweet, and it's a near miracle I have a cell phone let alone use a computer. I'm a Luddite. :-)
I understand your feelings re viXra, but since Cornell decided to shut people out and forget its original mission, shrug, what other choice you you have? One can upgrade later, and don't worry what LuMo thinks. His is but a voice in the wilderness. A very loud one yes, but if you can somehow work your QI thing into string theory, maybe he will sponsor you. Ask him.
Another thing Neil is it looks so much better for you in terms of the odds of some University or Lab running the experiment you propose if you have a professional-looking paper describing it exactly at a dedicated webpage on-line.
While this blogspot stuff is nice, a dedicated webpage in pure detail would be superior. Anyone who runs your experiment has a superior themselves, and that guy will probably only be impressed with the higher standards of Professionalism and presentation.
Just trying to help, bro.
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Thanks, Steven. I'm somewhat busy now but should get more time later. I'm also going to try emailing some people, I would think some people accept "suggestions" that way.
(PS, your dupe was deleted.)
Neil, click here and read about Sean Carroll's defense of MWI, a theory you and I both despise.
Thanks, Steven. Under the nomme de guerre of "uncle sam", I left some rebuttals you might find interesting (even if heard from me before.)
1. A similar model has been described in one-dimensional space. I suggest looking at that, though it's buried in the ancient (Carter-Reagan) physics/chemical physics literature.
2. What is causing the universe to expand if not the velocity of the devices or, in an energetic sense, their kinetic energy? So, this model seems to involve transformation of kinetic energy into potential energy. If my understanding is correct, then this universe would presumably later contract adiabatically.
3. In that formulation, this would seem to be an adiabatic expansion of the universe.
I'm not a physicist, but thinking about it in lower dimensions may make what's going on a little more intuitive.
Thanks for dropping by, phoenixwoman, and at such short notice. Re your point: I am supposing we have a universe that is "already expanding anyway" just from original force of some big bang etc, with things gradually decelerating from mutual gravity pull (but now whole subject complicated by dark energy issue.) In such cases "kinetic energy" is hard to define since it's all expanding together, but the same trade-off (velocity slows down as objects climb each others' gravity potential) applies.
So the stretching energy is extra, on top of anything else. The reason it's a "problem" is that, since each device is pulled on from all sides, there is no need to apply a separate, intrusive and "unbalanced" force (which would use up effort by whatever - like an arm - that applied it.) Energy increase without effort (loss somewhere else) violates conservation of energy. I'll try to find the one-dimensional case. It would be the same essential principle.
Hi Neil,
How have you been?
Chad Orzell is talking Quantum Interpretation again, here. He links to his old discussion with you.
The important point he has now taken a moderate, agnostic view of MWI, with decoherence.
tx for heads up, Steven. Chad never tells me! I'm headed over right now.
(and my Captcha for logging into blogger is "oughted.")
The scale of engineering required to make this work would be truly breathtaking. As far as the 'free' part goes, surely this method would be sapping 'dark energy' whatever that might be?
That said, I am not a physicist and can't quite get my head around the specifics of work being performed in and by an expanding metric, especially with regards to a Hookean potential versus a gravitational one.
Eutactic, this is not about dark energy. In a GR model w/o the DE, it seems to me we can't avoid a paradox resulting from having no "ends" for the spring system. When the all pull on each other, there is no place or need for anyone to exert force and pull. Each test body is pulled from six directions and the forces on each body cancel out, yet no one needs to pull since they are mutually interconnected (it's a "closed space" or an infinite space.) There are indeed subtle difficulties about defining energy in GR, but this is not the hard task of assigning energy to gravity fields and potentials themselves - it's the energy in the cables when they stretch.
(BTW, you can either have springs stretching and getting more "energy from nowhere" inside themselves, or you can use cables pulling on generators. Either way, the mutual forces on a body cancel so the body keeps moving out.)
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