New “cold fusion” results. It’s hard to believe that it’s been twenty years since Pons’ and Fleischmann’s original claims.
20 thoughts on “Here We Go Again”
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New “cold fusion” results. It’s hard to believe that it’s been twenty years since Pons’ and Fleischmann’s original claims.
Comments are closed.
This again. And, yet again, it’s being presented by an analytical chemist, who of course knows dick about nuclear physics.
Still, you’d think Pam (or her superiors at SPAWAR) could do a little back o’ the envelope calculation. Look up the range of the strong force. Calculate the Coulomb repulsive energy between two protons at that separation (wow!), then plug into Maxwell-Boltzmann to find the probability that two protons would be moving at the required speed when they collide. A number with a 3-digit negative power of ten in it.
I knew a guy back in the Pons day who went though the enormous labor to calculate the tunneling correction to this absurd number (when the protons get close enough, one can tunnel through the Coulomb barrier), achieving a number which was still absurdly low. And…er…who would be surprised? If, say, Jupiter, which contains massive amounts of H2 at densities far higher than you can pack any of this stuff into palladium isn’t shining by fusion light — well, what’s missing up there that’s present in a San Diego lab? The possibility of funding from “green energy” initiatives, I wonder?
What is it with the Navy and perpetual motion machines, anyway? They funded Gamgee’s “Zeromotor” back in 19th century, too (one of the more famous perpetual motion machines).
Incidentally, if anyone doesn’t already know about it, there is a genuine form of cold fusion, muon-catalyzed fusion, which played an amusing small part in one of Isaac Asimov’s later Foundation/Robot books. IIRC, Spacers developed a portable (!) particle accelerator that could produce a heavy stream of muons, thus provoking any modestly compact supply of water to undergo fusion, boom. I think this is how the turned the Earth’s crust radioactive.
It mystifies me while people get all excited about fusion energy, anyway. Given the energy scales, it would be like installing a J-2 engine in your car. But with that high exhaust velocity, it would be amazingly efficient! Er…yes…but there would be some practical difficulties…with gearing and such..
U.S. Navy’s Space and Naval Warfare Systems Center (SPAWAR) in San Diego, Calif.
Uh, what is SPAWAR doing studying cold fusion? Seems more like something NRL would be into.
Which brings up the original critique, that the research schools that had good football teams tended to get positive results and those with out (e.g. MIT, Cal tech) didn’t.
The possibility of funding from “green energy” initiatives, I wonder?
Yeah. Too bad for them they’re doing actual lab work rather than something that can’t be experimented upon in a meaningful way and which requires huge complex computer models to simulate.
That’s where the real bucks are.
Maybe that’s where the world’s entire supply of unobtainium is stockpiled, which has unpredictable effects on the laws of physics in its vicinity.
what’s missing up there that’s present in a San Diego lab? The possibility of funding from “green energy” initiatives, I wonder?
Carl, if you expect the greens are going to fund any kind of nuclear energy — fission/fusion, hot/cold, wet/dry — then you haven’t been paying attention.
The Navy also funds a practical fusion reactor based on Bussard / Farnsworth technology. The amount of money invested has been very low to date, but it has good promise. Does anyone at TT.com have any comments on this? My name has a link to one example.
I’m damned I know how the’re going to achieve any reasonable kind of flux. You can use a van de Graaf generator to smash single protons together hard enough to fuse. Getting 10^20 of them to do it at once, that’s the trick.
I don’t know dick about cold fusion (and doubt this is it) . . . but I AM pretty sure that chemists (even analytical ones) do quantum mechanics pretty well these days. The nice thing about science is that it doesn’t pay much attention to ad hominem.
Carl, your attitude reminds me of the archetypal French approach to engineering:
“Well yes, I admit it does work in practice … but does it work in theory?”
You seem to be saying that because your model can’t explain the data, the data must therefore be wrong? Perhaps the data are wrong or misinterpreted, but the only way to actually determine that is to investigate.
I’m fond of a line by Isaac Asimov:
I just have one question (well, two) for the scientists who say they’ve got something:
(1) Have you tried running your experiment with heavy water and then, as a control, with regular water? (2) If so, did you get different results depending on whether deuterium was present?
If the answers to (1) and (2) are both yes, then something interesting is going on here. If the answer to either one is no, then the scientists are crazy to have published. The MSM is not scientifically competent to ask either question, so we can’t find out unless we can get to the original publication. Or someone in the media could contact SPAWAR at 619-524-3432 and ask; perhaps a blogger could perform this service for us.
I don’t really care whether or not all our existing theories say cold fusion can’t possibly work. These are two perfectly straightforward, yes-or-no questions. If they’re yes, let me know and I’ll become very interested in the theories about what is or isn’t or might be or couldn’t be happening; if not, there’s nothing to see.
I’m interested in cold fusion as a sociological phenomenon. Critiques (with which I am in near-total agreement) of the physics are one thing. What to watch for is the people who are afraid that it, or something like it, will someday be made to work — the Paul Erlichs of the world, for whom keeping human capabilities hobbled has become a religion.
Look up the range of the strong force. Calculate the Coulomb repulsive energy between two protons at that separation (wow!), then plug into Maxwell-Boltzmann to find the probability that two protons would be moving at the required speed when they collide.
Not to defend bad cold fusion science, but there is a somewhat more respectable approach: pycnonuclear fusion. This involves extreme compression to overcome the coulomb barrier, rather than thermal energy (the Maxwell-Boltzmann distribution of energies you mention). If you compressed a mixture of hydrogen and deuterium, but kept it cold, you’d start getting H-D fusion (making 3He) without getting much D-D fusion. This is quite different from what would happen if you just heated the mixture; in that case the DD fusion would dominate (due to reactions out on the tail of the distribution).
BTW, even in thermal fusion, it’s not just the probability that the two ions will be energetic enough, it’s also the probability that, at close approach, they will tunnel through the remainder of the potential barrier (which classically is far higher than the mean ion energy in typical fusion conditions; fusion occurs at all only because of this tunneling, as Bethe pointed out in the 1930s.)
A few quick replies, gentlemen:
jrman, it happens I’ve taught quantum mechanics to analytical chemists, so I know exactly what they know, as a rule. You need to draw a distinction between knowing how to solve the Schroedinger equation for a particle in the box and knowing the right model to use for nuclear fusion. It’s somewhat like the distinction between knowing F=ma and being able to design a bridge.
Mike G, ha ha, yes, there is somewhat of that in the French approach to science. Kind of a top-down culture. Strangely enough, they still pull their weight in science. Must be some compensating quality elsewhere.
However, no, I’m not saying my theories can’t explain the data. You don’t have any inexplicable data here. You just have competing explanations: one conventional, boring, and one outrageous, exciting. By Occam’s Razor, I prefer the conventional one. Furthermore, if the outrageous one were true, there’s a whole lot of other data — the fact that the Sun isn’t much hotter, for example — that would now need explaining.
Asimov is quite right — he was a chemist, after all — and some of my own most interesting small discoveries have come from just that moment. It really pays to pay attention to inconsistencies, even small ones.
Paul, you’re right in theory, but have you asked yourself what kind of compression you need? Recall you need nuclei within the range of the strong force (femtometers). What is the density of a susbtance with of order 1 nucleus per cubic femtometer? You know the answer, of course — it’s the density of a neutron star.
I mentioned above that I had a friend, when we were both at Berkeley, who actually did the tunneling calculation for cold fusion. You still get ridiculous numbers. As you would expect, huh? It’s not like people don’t load H2 into palladium all the time — heck I bet there’s some in your car’s catalytic converter right now — and if it readily fused, even in teensy tiny percentages, we’d know by now. People talk about the right conditions, as if anything you do on an energy scale of eV is likely to change the landscape from a MeV point of view. It’s kind of like suggesting that there must be some clever way with a hockey stick and human arm strength to prevent the Titanic from sinking.
Furthermore, it’s certainly true that some cold fusion goes on all the time. If someone calculated that one fusion event per day happens in Earth’s oceans, I wouldn’t be surprised. The Boltzmann distribution has an infinitely long tail, in principle. With enough particles, some tiny number are bound to have as high an energy as you please. But just because rare events exist does not mean they can easily be made common. The existence of Bill Gates does not imply it is straightforward to get rich in computers.
Paul, you’re right in theory, but have you asked yourself what kind of compression you need?
The abstracts I’ve seen have claimed densities of several hundred times that of ordinary liquid hydrogen, and low temperature (1000 K). In these conditions the plasma is very strongly coupled, and close to the freezing point (where the ions settle into a lattice embedded in an electron gas). Electron screening would have a large effect on the tunneling rate.
Nuclear densities are not needed … the tunneling rate of hydrogen becomes significant (even without electron screening) at separations much larger than nuclear dimensions. Consider muon catalyzed fusion — the muon is 200 or so times the mass of an electron, so the internuclear separation in the muonic molecule, while much smaller than in normal electronic molecules, is still orders of magnitude larger than the size of a nucleus.
Hmm, still pretty distant, Paul. Since the Bohr radius goes like m^-1, because the muon is 200 times heavier the density of proton-muon pseudohydrogen is 200^3 = 8 million times higher than the density of ordinary hydrogen. That’s a long way from your density of 100x ordinary hydrogen. Another five orders of magnitude to go.
But of course you’re right, in the abstract. After all, this is what the Sun does. The temperature at its core is not nearly enough to start fusion at 1 atm pressure.
People made working steam engines before the laws of thermodynamics were known. Heck, Faraday was just a tinkerer and he managed to come up with many of the electromagnetic devices we use today. Only later did Maxwell come up with the theory to explain it. It used to be that practice preceeded theory. It was like that for most of the history of physics. Just because Einstein managed to come up with a theory which predicted physical effects that were only experimentally tested later on and proven, doesn’t mean all new physics is going to be that way.
If there is an interesting effect at work here that generates energy, then it should be studied, regardless if its fusion or not.
Everyone,
Thanks for expanding my knowledge on other methods of Fusion. Like Godzilla says, sometimes a tinkerer can do wonders. Farnsworth, the true inventor of T.V., started the Fusor program in the 50s and showed actual neutron production using basically a vacuum tube. He talked to Einstein (admittedly not an experimenter) and Einstein said he was on the right track. Bussard has combined it with magnetic confinement from Tokamaks. IMHO, I think this method of fusion has the best promise. Especially Boron-hydrogen fusion, which has no neutrons.
Carl:
Actually, you are wrong about the sun. The fusion in the solar core is thermonuclear, not pycnonuclear. The reactions there occur out on the tails of the thermal energy distribution. Those estimates about pycnonuclear fusion at a few hundred times normal hydrogen density involve electron screening effects that decline rapidly with increasing temperature.
You are correct that muon catalyzed fusion involves much high effective densities than the number for pycnonuclear fusion. But this misses the point — I was demonstrating that your claim about nuclear densities was wrong, not that muon catalyzed fusion was evidence for the lower figure I had given (it would be odd, wouldn’t it, if the muon mass were so precisely tuned as to just barely meet the lower limit on density for effective fusion.)
Mark wrote:
I just have one question (well, two) for the scientists who say they’ve got something:
(1) Have you tried running your experiment with heavy water and then, as a control, with regular water? (2) If so, did you get different results depending on whether deuterium was present?
I’ve been wondering about that, too. I’ve been looking at papers previously published by the SPAWAR team to see whether they did this. I haven’t found anything either way yet … which is troubling.
That said, I think that something new and so-far unexplained is going on. I strongly suspect that it isn’t cold fusion. Wouldn’t it be ironic and amusing if they had “merely” managed to construct a dark matter cosmic ray detector, or a tachyon detector?
(BTW, I used to work part-time at SPAWAR, as a student flunkey when I was in grad school. They called it the Naval Ocean Systems Center then.)
“I’ve been looking at papers previously published by the SPAWAR team to see whether they did this. I haven’t found anything either way yet … which is troubling.”
Yes … when the first team announced cold fusion 20 years ago, I read the popular accounts and became excited because it seemed to me the experiment would be so trivially easy to control — just see if you get different results with a heavy-hydrogen nucleus as with a light-hydrogen nucleus, and if you don’t then apparently something is going on that involves the nucleus — that I told myself, they couldn’t possibly have published without checking this and having the check give confirmation. Ergo, there “has to be” something novel going on here, and the story “has to be” interesting.
But it eventually turned out that they HADN’T done this obvious control. Boneheads. So I’m now disgustedly skeptical until I hear more.
All the quantum theorists can tell me is that cold fusion probably isn’t a good use of research resources, and that’s fine. But given that they’ve already done the research, I just want to know whether they’ve done my straightforward control with hydrogen; if so, and if against all expectation it worked, let’s hear more about it. If not, take the researchers out and flog them mercilessly with licorice whips, as an example to others.