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The cold fusion horizon

aeon.co

181–190 of 198 posts

Re: The cold fusion horizon

#181

Earlier quoted context omitted.

> This article is funny. It tries to do an end-run around any criticism of the subject matter by constructing an elaborate piece of work to establish that if you don't agree with the basic premise of low energy nuclear reactions there must be something pathologically wrong with you. It's really quite the other way around: the opponents of LENR research have treated everyone working on it as if there were something pa…

I'm not aware of any scientist that 'opposes LENR', I am however aware of a lot of scientists (and lay-people for that matter) that are skeptical of Rossi. And most scientists will take a much harder look at anything LENR related before committing their names and reputations to it leaving the field wide open to the fringe, with predictable results. It's not dis-similar to how people working on AI would call it anythi…

> I'm not aware of any scientist that 'opposes LENR'

Say what? From the article:

Ever since 1989, in fact, the whole subject has been largely off-limits in mainstream scientific circles. Authors who do put their head above the parapet are ignored or rebuked. Most recently, Lundin and Lidgren reported that they had submitted their paper to the journal Plasma Physics and Controlled Fusion, but that the editors declined to have it reviewed; and that even the non-reviewed preprint archive, arxiv.org, refused to accept it.

This is not just about Rossi by any means; he showed up relatively recently. This goes all the way back to Pons and Fleischmann. I wish I could remember the name of the physicist whose career was destroyed for no more than being publicly seen to entertain the possibility that cold fusion could be real.

Read up on this a little bit -- you'll see that pretty much the entire physics establishment opposes LENR.

> being oversold makes a field toxic

Yes, and there certainly has been some overselling. Even if P&F's work had been replicated, one could legitimately criticize their handling of the situation (it appears that the University of Utah, their employer, had a hand in this). But can one seriously suggest that because some researchers made premature announcements and oversold what they had actually accomplished, we should punish them by denying humanity what would be an almost miraculous invention, if it could be made to work? That makes just no sense at all, but that's pretty much how the physics establishment reacted.

Re: The cold fusion horizon

#182
post #152

Earlier quoted context omitted.

> Producing even a little heat with fusion produces a lot of nasty radiation. As in kill everyone in the unsheilded room within a few seconds. This is greatly exaggerated. The amount of excess heat they claimed to observe was really quite small, and D-D fusion produces a relatively weak neutron flux [0]. I'm not saying some shielding wouldn't have been a good idea, but instant death? No. [0] https://en.wikipedia.org/…

100Mev+ X-Ray / Gamma radiation is not fun. There is some play in the numbers based on type of fusion, but ~1w is on the order of 10^12th reactions per second and flat out lethal. Sure, if a device is weak out 1 millionth of that then it's not a big deal, but nobody cares about 0.000001 watts / second.

You didn't even click the link. Neutrons from D-D fusion are at 2.45 MeV.

Re: The cold fusion horizon

#184
post #173

Earlier quoted context omitted.

Based on those models, what circumstances are required for quantum tunnelling to occur?

Loosely the main points are that the rate falls off exponentially with the "width" of the barrier, and that energy is still conserved (you can say the particle "must have" had more energy at some point because it crossed the barrier, but you'll never observe it with more energy than it has). For more precise answers, just plug the potential you're trying to tunnel through into the Schrödinger equation.

You're referring to the 'Gamow window' right? From what I understand, the Gamow window only refers to the energy levels of the particles, rather than temperature per se. I'm guessing that's why approaches like Muon-catalysed fusion can work at lower temperatures.

https://en.m.wikipedia.org/wiki/Muon-catalyzed_fusion

Re: The cold fusion horizon

#185
post #152

Earlier quoted context omitted.

100Mev+ X-Ray / Gamma radiation is not fun. There is some play in the numbers based on type of fusion, but ~1w is on the order of 10^12th reactions per second and flat out lethal. Sure, if a device is weak out 1 millionth of that then it's not a big deal, but nobody cares about 0.000001 watts / second.

You didn't even click the link. Neutrons from D-D fusion are at 2.45 MeV.

Yea, I was off by a factor of 10.

https://en.wikipedia.org/wiki/Equivalent_dose 1W of 2.5Mev neutrons ~= 10W worth of Gamma Rays in terms of equivalent dose. (http://ocw.mit.edu/courses/nuclear-engineering/22-01-introdu...) There are several 14.1+Mev fusion products see chart: https://en.wikipedia.org/wiki/Nuclear_fusion (Which is probably where I was thinking 100Mev), but it’s already normalized so we are talking 10W equivalent.

Granted that 10W dose equivalent is not focused so a person standing next to it might get 8% of that which is .8W, or ~0.01W/kg equivalent (for a 80kg person) which just happens to be ~1 Rads per second. (1 rad = 0.01 Gy = 0.01 J/kg. 250 to 500 rads is the LD/50.

So, Standing next to an unshielded 1W neutron source has a 50/50 shot giving you a lethal dose within ~4 to 9 minutes.

PS: 2.5Mev Neutron radiation @ 1J per kg is ~10 Gy which is ~LD100 and probably where I was thinking 1W = death.

(Please double check my math.)

Re: The cold fusion horizon

#186
post #173

Earlier quoted context omitted.

Loosely the main points are that the rate falls off exponentially with the "width" of the barrier, and that energy is still conserved (you can say the particle "must have" had more energy at some point because it crossed the barrier, but you'll never observe it with more energy than it has). For more precise answers, just plug the potential you're trying to tunnel through into the Schrödinger equation.

You're referring to the 'Gamow window' right? From what I understand, the Gamow window only refers to the energy levels of the particles, rather than temperature per se. I'm guessing that's why approaches like Muon-catalysed fusion can work at lower temperatures. https://en.m.wikipedia.org/wiki/Muon-catalyzed_fusion

Muon-catalysed fusion reduces the width of the barrier - the muon is ~200 times closer to the nucleus (since it's that much heavier) and so the coulomb barrier is that much narrower - and the reaction rate is exponential in that.

Re: The cold fusion horizon

#187

Earlier quoted context omitted.

A reasonable guess, the only counter factual is that a number of people who are not fools seem to have convinced themselves that there is something there but they don't know what. And as the article points out there are a number of labs around the world that have independently seen results that were anomalous with respect to the current understanding of how things should work chemically. So if nothing else there is a…

It's very common for people who are totally not fools to get sucked into free energy scams. This is one of the better ones being demonstrated at the technical univeristy of Delft I believe: https://www.youtube.com/watch?v=mHW6b1aFPfU https://www.youtube.com/watch?v=uKCEceWs-Gc

That's amazing. He comes across like such a "magician".

An illusionist like "yes, take a look inside the machine!"

Re: The cold fusion horizon

#188
post #186

Earlier quoted context omitted.

You're referring to the 'Gamow window' right? From what I understand, the Gamow window only refers to the energy levels of the particles, rather than temperature per se. I'm guessing that's why approaches like Muon-catalysed fusion can work at lower temperatures. https://en.m.wikipedia.org/wiki/Muon-catalyzed_fusion

Muon-catalysed fusion reduces the width of the barrier - the muon is ~200 times closer to the nucleus (since it's that much heavier) and so the coulomb barrier is that much narrower - and the reaction rate is exponential in that.

Sure, it makes sense that it affects the Coulomb barrier (or the Gamow factor/window https://en.m.wikipedia.org/wiki/Gamow_window ), but doesn't muon-catalysed fusion kind of prove that cold fusion could exist? The Wikipedia article suggests that the reactions can take place at room temperature, with the main issue being the reliability of the required reactions.

In other words, we already have one proven method for reducing the Coulomb barrier, why is that the only one that's possible?

Re: The cold fusion horizon

#189
post #163

The article seems to be lost on a large number of commenters who are asserting (or almost asserting) that this is a scam because (1) Rossi seems to have a dubious history (I'm only going by the comments, not my own investigation) and (2) Rossi is secretive (3) Rossi is not a notable scientist from a top-tier University (4) Rossi comes across as overconfident. This is what the article is pointing out. The author is sa…

This sounds like a case of "Pascal's mugging" - the idea that we should be willing to pay for a very small chance of an extremely good outcome, because the expected value is high. There are arguments over how to resolve it, but taking it literally certainly leads to bad outcome. There is a virtually limitless supply of cranks claiming to have cold fusion, and I would bet a lot of money that none of them do.

Since there is Scientific advances are made when someone accomplishes what others thought was impossible. I haven't seen anything in the physics to indicate that you'd be breaking (known) laws of physics. It seems that this article was written for people such as yourself.

Re: The cold fusion horizon

#190

Earlier quoted context omitted.

> I don't think it's fair to lump those two together. Heh, I disagree. I hold almost the exact opposite view and believe it is perfectly fair to lump those two together. Cold fusion requires overcoming the Coulomb barrier at room temperature. Do you have any idea how impossible that is? It's just as impossible as accelerating an object faster than light, or me spontaneously quantum tunneling through my floor into my…

You mentioned the Coulomb barrier makes this impossible. Can you comment on this story about Edward Teller? https://news.ycombinator.com/item?id=10780632 Seems to me it's not proven beyond doubt that it's impossible. Furthermore, even if it does prove to be impossible it could turn out to be a 'useful mistake' if new science needs to be developed to explain the phenomena that were once labelled as 'cold fusion', that…

> Can you comment on this story about Edward Teller?

It's an anecdote of an anecdote. It's literally third person hearsay, with Teller saying "Oh, it "might" be possible". We don't even know he said that. Even on the off-chance he did, it means practically nothing. There are similar wordings and phrasing done about breaking light speed from respected physicists. You could probably get one to say "might" as well. It doesn't mean there's any validity behind it. The point and facts still stand - you're not going to break the Coulomb barrier at room temp. It's an impossibility.

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