9 ms·
According to quantum mechanics, the probability of a D-D fusion reaction at 300°K is ~10^-3800. That being said, I still think it's wrong of mainstream science
by Everhusk 10y ago
According to quantum mechanics, the probability of a D-D fusion reaction at 300°K is ~10^-3800.
That being said, I still think it's wrong of mainstream science immediately reject Cold Fusion/LENR or even Em Drive research.
Just take it for what it is, an anomaly. Which may or may not lead to a breakthrough.
- api 10y agoIt couldn't be fusion -- at least not anything like hot fusion. If it is something like fusion, it'd have to be new physics.
- deleted 10y ago[deleted]
- greglindahl 10y agoExtraordinary claims require extraordinary proof. When it's mostly likely experimental error, why do you think anyone should "take it for an anomaly"?
- golergka 10y agoExtraordinary claims require extraordinary proof to take them as truth. Less extraordinary proof can still let them be a "may be". That's all they're trying to be for now.
- greglindahl 10y agoI was responding to someone who said "it's wrong of mainstream science immediately reject Cold Fusion/LENR or even Em Drive research". In response to you, "unlikely" is not the same as "may be".
- snowwrestler 10y agoIt not good science to reject a hypothesis or anomalous result before the data makes clear what is going on. Imagine if the guys at Bell Labs had just said "eh, who knows, nevermind" when they couldn't figure out the hiss in the horn antenna.
- greglindahl 10y agoThere was no theory saying that the horn antenna should have no hiss. It was a classic example of being the first measurement of a thing. It happens all the time in astronomy. Since this measurement people have been much more open to whatever the data says when they observe in a new frequency band. If anything, the surprise in this particular case was mainly because the people doing the experiment weren't astronomers, and had never considered what they might see if they looked up. Excellent discovery, and easy and inexpensive to replicate.
- snowwrestler 10y ago> There was no theory saying that the horn antenna should have no hiss. Then why did they go to such extraordinary lengths to find the source of it? Why didn't they just shrug and work around it? Keep in mind they initially had no knowledge of the theoretical prediction of CMB, which was fairly recent and controversial. They just had a weird observation and busted their butts trying to figure out what it was. > It was a classic example of being the first measurement of a thing. Yes, now we know that. At the time it was not clear that it was a phenomenon worth measuring at all. I mean, they thought it was pigeons. It looked like a dumb error at first. > Excellent discovery, and easy and inexpensive to replicate. The "emdrive" is also easy and cheap to replicate. I'm not saying that the emdrive works, I'm saying that experimental results matter. They should not be dismissed just becaus me they seem to violate theory. Violating theory is why people experiment in the first place.
- greglindahl 10y agoWell, they were mostly weirded out that it was the same hiss no matter where in the sky they pointed the horn, and indeed, that's pretty weird. It was non-obvious, and now we know why. For the emdrive, the effect is so small that it's suggested that the next step is to launch a powerful satellite costing $100mm or more. Uh, really? From your comment, you seem to be tangled up in results being "dismissed". That's not what's going on, when people make comments about extraordinary claims and extraordinary results. A tiny, hard to measure result is not an OH MY GOD THE THEORY IS WRONG result. It is likely an experimental error.
- AnimalMuppet 10y ago"May be" covers everything from "unlikely, but not quite impossible" to "almost but not quite certainly true". A couple of times in this discussion, you've argued about the definitions of words, and your definitions have been... at least different from the way the words are normally used. It's kind of distracting from the actual discussion, without adding much.
- greglindahl 10y agoWell, sorry, I'm trained in physics. It's the way we use those words.
- AnimalMuppet 10y agoHmm. I'm trained in physics, too, to some degree, but I stopped at a bachelor's degree. What, in your usage, is the difference between "unlikely" and "may be"? (By the way, I'm not arguing against "unlikely" wrt any of these things...)
- greglindahl 10y ago"may be" doesn't give you an idea if it's 50% or 1% or 0.0001% likely. "Unlikely" does give you an idea: the probability is small. When you're talking about an extraordinary claim, it's a good idea to use "unlikely" and not "may be". The moon "may be" has deposits of green cheese, we just haven't found them yet. It is unlikely that the moon has deposits of green cheese. It is likely that the EM Drive thrust measurement is measurement error.
- dekhn 10y agoScience writing, especially the hard core sciences, has a collection of terms that are used among practitioners and have very specific meanings that are well-understood. These usages convey fairly subtles signals about one's understanding of, and confidence in, a physical phenomenon. This is typically only learned by people who write papers and have advisors who can guide them. A really nice example of this which is also immediately readable is Watson and Crick's 1953 DNA structure paper. http://www.nature.com/nature/dna50/watsoncrick.pdf http://www.nature.com/nature/dna50/watsoncrick.pdf It's a classic understated style, with a small amount of boastful brilliance. The passive tone is a bit dated, but you can clearly see little was known about how DNA worked, and they were very careful not to make any strong claims without qualifiers.
- dekhn 10y agoActually extraordinary claims require no more proof than any other. Otherwise, you're prone to accepting ordinary claims with less evidence.
- onion2k 10y agoYou don't often go from "nothing" to "proof it works" in a single iteration of a new technology.
- greglindahl 10y agoIndeed, if you look at the history of science, even modern examples such as the discovery of H. Pylori, it's a messy process. However, don't be confused by survivor bias: almost all extraordinary results turn out to be experimental error.
- snowwrestler 10y agoFine, but let's also recognize that this is not yet one of them. It might be an error, in fact it almost certainly will be. But it is not yet certainly an error. Stand back: science still in progress!
- Retric 10y agoBut you should not be trying to prove it works. You should be trying to disprove it, until no other reasonable explanation is left. The most obvious example is to use normal water instead of heavy water and see if you get similar results.
- Everhusk 10y agoAgreed. However, rather than ignoring the experiment, I think it would be better to encourage scientists to understand why. “Whatever Nature has in store for mankind, unpleasant as it may be, men must accept, for ignorance is never better than knowledge.” ― Enrico Fermi
- greglindahl 10y agoI didn't suggest ignoring the experiment. I'm just setting a baseline for how important this result is.
- AnimalMuppet 10y agoWell, if it's experimental error, then we learn a bit more about how to properly and carefully conduct experiments. If it's not experimental error, though... Unfortunately, you have to look into it carefully to find out whether it's experimental error or something more interesting. And, to return to Everhusk's first post: Experimental error can result in an "anomaly". The experiment is not returning the results we expect. That's an anomaly. An anomaly doesn't have to be new physics.
- jcoffland 10y agoBut you cannot get to extraordinary proof of you immediately reject the idea.
- greglindahl 10y agoUm, I didn't immediately reject the idea.
- jcoffland 10y agohttps://en.wikipedia.org/wiki/You#Informal_plural_forms https://en.wikipedia.org/wiki/You#Informal_plural_forms
- flukus 10y ago> or even Em Drive research I think a lot of those rejections are coming from the crazy claims the EM drive inventor is making, everything from free energy to flying cars.
- api 10y agoYes, and the theories which seem to be nonsense according to most physicists I've read. If you stick to the pure experimental aspects of "we put a microwave in a can and obtained these anomalous results" and ignore everything else, there's something interesting there that bears investigation.
- CamperBob2 10y agoThe big problem with all of the positive results from the EMDrive experiments is that -- without a single exception AFAIK -- the observed thrust doesn't stop immediately when they kill the power. It decays exactly as you'd expect if you were watching something cool off. Obviously that's a very strong and obvious indication of experimental error.
- flukus 10y agoGiven a perfect experimental setup, would we expect the microwaves to keep bouncing around infinitely or to escape immediately?
- CamperBob2 10y agoThe radiation would die away pretty quickly. It would be determined by the cavity Q, basically. Think about a bell that takes a long time to fall silent after it's rung. With radio waves near c instead of physical acoustic vibrations, you'd need an insanely high cavity Q, well into the millions, to keep the energy from dying out in milliseconds. But cavities used in this type of experiment probably don't exceed Q=1000. This kind of "ringdown" effect can be observed at human-compatible timescales at low HF frequencies in crystal resonators. But only a fast oscilloscope will let you observe it in a cavity.
- macspoofing 10y ago>I still think it's wrong of mainstream science immediately reject Cold Fusion/LENR or even Em Drive research. You have to focus on something - there are only so many grant and R&D dollars to go around
- jcoffland 10y agoAnd those dollars should be spread around to different ideas not just to research that which we assume to be true.
- greglindahl 10y agoEvery physics department in the world gets a constant stream of letters and emails from people claiming important theories which should be researched. How do you propose picking which ones to spend money on?
- cgio 10y agoRandomly
- Turing_Machine 10y agoThat's an interesting idea. Of course, most apparently whackadoodle ideas really are whackadoodle ideas, but occasionally you get one that isn't, and when that happens, it's usually big. Perhaps a (small) budget randomly assigned to whackadoodle ideas might be a good thing. Like venture capital for science -- most of the theories are going to crater, but once in a while you might get a unicorn.
- inimino 10y agoGive them to undergrads.
- B1FF_PSUVM 10y ago
- jcoffland 10y agoWe already know for a fact that quantum mechanics is an incomplete theory. It fails to accurately describe gravity. A fundamental force of nature. Therefore we should expect that it fails to explain other phenomena as well.
- greglindahl 10y agoYes, and it doesn't appear that any of the weird things under discussion in this case have anything to do with a GUT or TOE. The important thing to remember is that theories like Newton's Law do a great job in a large number of regimes -- you have to look at things like the precession of Mercury or an atomic clock in orbit to see why Einstein is needed.
- lisivka 10y agoI believe, if we take in account wave-particle duality, then we will be able to explain large parts of General Relativity using Newtonian physics, because waves are propagating, so second postulate is obvious, for example.
- duaneb 10y agoNewtonian laws are excellent for intuition about human-scale problems. What do we gain from modeling GR that way?
- lisivka 10y agoIntuition at GR-scale problems. Why I need to believe in Einstein postulates if I can just look at walking droplet 2D model of QM and see that these postulates are obvious?
- raattgift 10y agoWhy do you need to consider Einstein's postulates if you can just look at a ball traversing a rubber sheet with a depression in it, for that matter? Same answer: because these rough analogues are not background-independent -- you would see a very different picture in each case if you moved the walking droplet or rubber sheet setups to the moon or to the ISS. Einstein GR postulate number one: microscopic physics is background-independent. These experiments' microscopic details behave the same on Earth, on the moon, and in the ISS, but their macroscopic behaviours sure don't. You have to input details of the local structure of spacetime into each of them if you want to predict their results (e.g., what trajectory the walk takes, or how long it takes for a ball to reach the bottom of a depression in the rubber sheet) successfully.
- rtpg 10y agoMy understanding is that, while cold fusion might require some previously unknown interaction, Em Drive's issues are a bit more fundamental. If the Em Drive works, it invalidates a lot of mathmatical equalities that are derived from the fact that electro-magnetism works through fields. So you're basically invalidating the fundamental nature of electro-magnetism, not "just" conservation of energy
- rdlecler1 10y agoFinding the cause of an anomaly is when the magic happens--that's where you learn something new, even if it's something driving systematic experimental error.
- gus_massa 10y agoIs that an anomaly or just an experimental error? All the reports of the Em Drive are not conclusive. The force that they are measuring is very small and very close to the experimental error. It looks more like involuntary p hacking that a good incontrovertible experiment. I was not following the resents advances of the LENR. IIRC they heat a device with an electric current and they estimate how much heat it release. Measuring heat is a very difficult task, so the measurements are problematic. The additional heat is not too much. They don't have a device that can autosubstain the reaction, and that can silence all the critics. If you want an to see how the physic community reacts to an anomaly, consider the high temperature superconductors. They are clearly impossible, well at least unbelievable, and the old theory forbid them. But 20 years ago they gave a foolproof method to build a high temperature superconductors in a good lab. The experiments were conclusive. You can even tweak the recipe and get a better superconductor. You can put them under high pressure and get more temperature. You can make many experiments with them. But still there is no good theory to explain how they work. Someone told me that the explanation was flux pinning, but apparently it still disputed and perhaps that explanation is wrong. But anyway, in spite there is no good theoretical explanation, you can make conclusive experiments with an relatively easy to build superconductor and some liquid nitrogen. Mainstream physics love anomalies. You can get a Nobel price for confirming or explaining it. You can enclose a few graduate students to study it. You can get money from grants. But you must have to ensure a minimal probability that the anomaly is real, because you must release the graduate students someday ...
- deleted 10y ago[deleted]
- Everhusk 10y agoThere have been some reports of 4He and some high energy particle emissions, consistent with D + D → 4He + 23.8 MeV (heat) [1]. So yes, I would say there have been enough experiments done to call it an anomaly. I believe what makes it so hard to tell is the labelling of any cold fusion researcher as a crackpot, which seems to have forced it 'underground'. Certainly a valid social experiment in physics if nothing else! [1] http://lenr-canr.org/acrobat/Hagelsteinnewphysica.pdf http://lenr-canr.org/acrobat/Hagelsteinnewphysica.pdf
- lisivka 10y agoYou calculated probability with wave function in mind, right? What if particle will collapse it wave when it is under a barrier (due to an impurity)? IMHO, without their waves, two particles can interact freely. High voltage and frequency are forcing atoms of hydrogen to jump frequently across impurities, so chance of reaction is increased a lot.
- Lewton 10y agoThere are a couple of reasons to come down on stuff like cold fusion and em drives hard. One of them is that of limited funding, there's almost definitely better places to spend money if the goal is progress Another is how these claims set back scientific literacy of the general public And how it can erode their trust in science Look at how the ftl neutrino debacle did damage, even though no actual claims were made
- deleted 10y ago[deleted]
- im3w1l 10y agoI assume your figure describes the probability of D-D fusion in pure deuterium at NTP? Is that correct? Chemistry has a concept of a catalyst - Something that lowers the activation energy of a reaction thus increasing reaction rate. Why couldn't nuclear catalysts exist?
- Everhusk 10y agoEssentially, yes that is correct. I based it on the cross section of Deuterium at NTP. A chemical cataylst is a bit different because it doesn't require overcoming the coloumb barrier. If a nuclear catalyst existed, it would have to lower to almost no energy or even bypass the coloumb barrier for a D-D fusion reaction to occur at NTP. Do you know of any situations were the coloumb barrier has been altered?
- im3w1l 10y agoI looked into it, and Muons can apparently be used as catalysts https://en.wikipedia.org/wiki/Muon-catalyzed_fusion https://en.wikipedia.org/wiki/Muon-catalyzed_fusion. They are supposedly very energy intensive to be produce, but it proves the concept of lowering the barrier.
- Symmetry 10y agoThe important thing for fusion isn't the average energy of the particles in your ensemble but the number of particles with energies around 15keV for D-D fusion. In the case of this experiment there was a potential of around that many volts around that palladium and if, theoretically, some deuterium could pick up a charge and cross that potential without running into anything else and then managed to run smack into another deuterium at the far end it had a high chance of fusing. There wasn't any a priori reason to think that those events would be common or uncommon and so barring experiment there wasn't any reason to dismiss cold fusion out of hand for temperature reasons. The lack of gamma rays was pretty significant evidence, though.