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  #1  
Old 03-17-2005, 02:17 PM
Avumede Avumede is offline
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Has cold fusion been replicated?

From this interesting article at New Scientist:

Quote:
AFTER 16 years, it's back. In fact, cold fusion never really went away. Over a 10-year period from 1989, US navy labs ran more than 200 experiments to investigate whether nuclear reactions generating more energy than they consume - supposedly only possible inside stars - can occur at room temperature. Numerous researchers have since pronounced themselves believers.
New Scientist hints that cold fusion has been replicated, but doesn't actually come out and say it. Has it? Is there really good reason to think that cold fusion is real?
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  #2  
Old 03-17-2005, 02:42 PM
mittu mittu is offline
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www.answers.com throws up the following:

Quote:
cold fusion

The fusion of hydrogen atoms into helium at room temperature. In 1989 two scientists announced that they had produced cold fusion in their laboratory, an achievement that if true would have meant a virtually unlimited cheap energy supply for humanity. When other scientists were unable to reproduce their results, the scientific community concluded that the original experiment had been flawed.
and

Quote:
The noun cold fusion has one meaning:

Meaning #1: nuclear fusion at or near room temperatures; claims to have discovered it are generally considered to have been mistaken
It seems work is still going on so someone may yet unlock the secrets of cold fusion but it doesn't appear anyone has done it so far.
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  #3  
Old 03-17-2005, 02:47 PM
CynicalGabe CynicalGabe is offline
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Quote:
Originally Posted by Avumede
Is there really good reason to think that cold fusion is real?
No.
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  #4  
Old 03-17-2005, 02:58 PM
Level3Navigator Level3Navigator is offline
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Quote:
Originally Posted by Avumede
Is there really good reason to think that cold fusion is real?
Hmmm.. a subject on which I can actually throw in a few irrelevances. Note that IANAPhysicist but I did used to work with the son of one of the two scientists that claimed cold fusion back in the day. He had worked in the labs with his father and had a pretty good grasp of it, although he was also not a physicist.

That being said, he stated that cold fusion was occuring, but getting to the state where it would occur would consume more energy than they were getting out. I recall something about the presence of muons, but my memory is pretty hazy on this. So take this with a large grain of salt.

But, yes, I was once close to greatness, in a rather distant way..
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  #5  
Old 03-17-2005, 03:26 PM
Avumede Avumede is offline
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The same article also states:
Quote:
In December, after a lengthy review of the evidence, [the Department of Energy] said it was open to receiving proposals for new cold fusion experiments.
I wonder what evidence convinced them? I'm as skeptical as the rest of the posters on this thread, but I wonder if I'm just not up on the latest. Or is the DoE's openness to receiving proposals not indicative of any belief that there is anything "real" there?
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  #6  
Old 03-17-2005, 04:00 PM
Finagle Finagle is offline
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There's some slight evidence for sonofusion (fusion caused by collapsing bubbles caused by soundwaves). People are far from generally accepting it, but I could see where the government might be persuaded to fund future research to see if there's anything there.
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  #7  
Old 03-17-2005, 04:46 PM
Worzo Worzo is offline
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A Physicists View

Friends!

I spied your musings on this "cold fusion" and thought I might put in my "two cents" (although it would be tuppence here in good old Britain).

Being a physicist, I have this to say about the fundamental concept of cold fusion:

In order to fuse two hydrogen atoms to make helium, and thus release the enormous amount of binding energy, one must overcome the huge electrostatic repulsion between the hydrogen atoms. Unfortunately, forces of this magnitude only occur when there is immense pressure between the atoms, such as in a star.

Given that these kind of pressures are impractical here on Earth, the only way to get the atoms close enough together so that nuclear binding forces take over is to give the hydrogen atoms a huge amount of initial kinetic energy i.e. they have to get moving pretty quick.

This kinetic energy can either come from the atoms being accelerated very quickly towards each other (i.e. particle accelerator), or from them being very hot and randomly moving around very quickly.

Hence, in order for fusion to occur, I would have to say that high temperatures are required and that there is no way it can occur at room temperature, and certainly no way it can occur by any of the chemical reactions that people have been trying.

I thank you gentlemen,

Andy.
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  #8  
Old 03-17-2005, 07:05 PM
bonzer bonzer is offline
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Quote:
Originally Posted by Avumede
I wonder what evidence convinced them? I'm as skeptical as the rest of the posters on this thread, but I wonder if I'm just not up on the latest. Or is the DoE's openness to receiving proposals not indicative of any belief that there is anything "real" there?
While I haven't seen any detailed report produced by the DoE's most recent review, the conclusion was more along the lines of "we can't be sure it's impossible, so we're still prepared to look at individual proposals". Given that the pressure for undertaking the review was - as you'd expect - very pro-cold-fusion, one can argue that this was relatively negative.
Or, taking a more historical perspective, the US funding authorities' stance on the matter is currently much the same as it was back in the late-1980s before all the fuss in 1989. So not much progress towards convincing anybody there then.

The US Navy laboratory research that's quoted in the OP has been around for quite some time. There's even another New Scientist feature from about 3-4 years back, this time specifically devoted to it. As I recall, even the researchers involved were quoted as being extremely tentative and were only prepared to claim that more research was needed.


Quote:
Originally Posted by Level3Navigator
Note that IANAPhysicist but I did used to work with the son of one of the two scientists that claimed cold fusion back in the day. He had worked in the labs with his father and had a pretty good grasp of it, although he was also not a physicist.
Joey Pons?
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  #9  
Old 03-17-2005, 08:32 PM
ambushed ambushed is offline
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Quote:
Originally Posted by Avumede
The same article also states:


In December, after a lengthy review of the evidence, [the Department of Energy] said it was open to receiving proposals for new cold fusion experiments.
This means nothing. Remember that the CIA granted significant contracts through a quasi-reputable defense company (SAIC) to explore psychic "remote viewing", and even though the experiments were stupid and wildly unsuccessful, the government wanted to go ahead with the project for some time until wiser heads prevailed.

I believe that the only reason the DOE is open to new CF proposals is because of political pressure, not scientifiic credibility.
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  #10  
Old 03-17-2005, 08:54 PM
bonzer bonzer is offline
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A little extra digging uncovered the DoE's Report of the Review of Low Energy Nuclear Reactions from last December. It's a five page dismissal that indeed says they haven't changed their minds since 1989.
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  #11  
Old 03-18-2005, 04:31 AM
eagle eagle is offline
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Hi Worzo,

IANAphysicist, and I have have no doubt about the "facts" you describe. They are correct. What I question is your conclusion: It is not possible!

Let me remind you: Otto Hahn was a chemist who researched about "transuranium". The common scientific belief at that time was, that shooting neutrons on uranium will produce the heavier elements. 1938 he did an experiment that should prove this hypothesis but instead of heavier elements he actually found lighter elements, "radiothorium" to be exact.

It took him a year of repeated experiments, until he believed his own experiments, and it was Lise Meitner who proposed the theory of fission in 1939 that explained the results.

Now if you had asked the world's best physicists in 1937, if they believe, that atoms could be broken apart, they would have said: This is not possible!

Do you still think, that saying "It is not possible!", is a sufficient cause to abandone all research on Cold Fusion?

It might be soemething else from Cold Fusion. It might an errorneous experiment. It might even be a hoax. But right now, we have no commonly accepted explanation. So resarch should go on. And that is the position the DoE has, even though they currently see no point in funding such research.

cu
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  #12  
Old 03-18-2005, 05:22 AM
Desmostylus Desmostylus is offline
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Quote:
Originally Posted by bonzer
Quote:
Originally Posted by Level3Navigator
Note that IANAPhysicist but I did used to work with the son of one of the two scientists that claimed cold fusion back in the day. He had worked in the labs with his father and had a pretty good grasp of it, although he was also not a physicist.
Joey Pons?
I think he means an earlier day than that. He could well be talking about geologist Walter Alvarez (of dinosaur extinction K-T layer fame), son of 1968 Nobel Physics Laurate Luis W Alvarez, who discovered cold fusion in 1957.

Note that Luis W Alvarez's results are readily reproducible, and easily disprove Worzo statement: "Hence, in order for fusion to occur, I would have to say that high temperatures are required and that there is no way it can occur at room temperature..."
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  #13  
Old 03-18-2005, 07:11 AM
eagle eagle is offline
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Quote:
Originally Posted by Desmostylus
Luis W Alvarez, who discovered cold fusion in 1957.

Note that Luis W Alvarez's results are readily reproducible
Yery interesting. Could you provide a link that describes his experiment in detail? I tried to google, but all I came up with, was a two line stmt, that this experiment indeed exists, but did not produce a useful amount of energy.

cu
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  #14  
Old 03-18-2005, 07:23 AM
bonzer bonzer is offline
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Quote:
Originally Posted by Desmostylus
I think he means an earlier day than that.
Except I didn't pick the name at random. That one of Pons's sons was involved in some of the experiments, and had co-authored some papers with his father, is a matter of record; see the references to him in Bad Science (Random House, 1993) by Gary Taubes.


Quote:
He could well be talking about geologist Walter Alvarez (of dinosaur extinction K-T layer fame), son of 1968 Nobel Physics Laurate Luis W Alvarez, who discovered cold fusion in 1957.
It's certainly possible that the 17 year old Walter was working with his father in some capacity on the Bevatron at the time, though I'll note that Luis doesn't mention him in this connection in the account of discovering muon-catalysed fusion in his autobiography.
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  #15  
Old 03-18-2005, 07:41 AM
Desmostylus Desmostylus is offline
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Quote:
Originally Posted by eagle
Yery interesting. Could you provide a link that describes his experiment in detail? I tried to google, but all I came up with, was a two line stmt, that this experiment indeed exists...
Alvarez simply observed the phenomenon in a cloud chamber.
Quote:
Originally Posted by eagle
...but did not produce a useful amount of energy.
Which is what Level3Navigator said:
Quote:
Originally Posted by Level3Navigator
That being said, he stated that cold fusion was occuring, but getting to the state where it would occur would consume more energy than they were getting out. I recall something about the presence of muons, but my memory is pretty hazy on this.
Try googling "muon catalysed fusion". The basic concept is that two muons, a deuterium nucleus and another deuterium (or tritium) nucleus form a hydrogen molecule. Muons are much more massive than electrons, and force the two nuclei much closer together than in a normal hydrogen molecule. Close enough undergo fusion.

The energy required to produce the muons is greater than the energy resulting from the fusion.
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  #16  
Old 03-18-2005, 07:53 AM
matt matt is offline
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A whole bunch of different things are being discussed under the umbrella of "cold fusion" here.

First, there is muon-catalysed cold fusion. This uses a heavy particle called a muon, which has the same charge as an electron but a much greater weight. It can substitute for the electron in atoms of hydrogen and its isotopes. These "muonic" atoms can undergo fusion at relatively low temperatures, around 900 deg C is optimum if I recall correctly.

The catch is, muons are unstable and decay, and they take energy to create. To get beyond break-even, you have to achieve a number of fusions per muon before each muon decays. So far, nobody has got enough fusions per muon to get net energy out. But this cold fusion is real, it works and has been demonstrated to work. It just isn't actually useful.


Second, there are the "electrochemical" cold fusion experiments, where people use electrolysis to force hydrogen isotope atoms into a block of solid metal, usually platinum or similar. A number of claims have been made about this - claims of net energy production, tritium production, neutron detection, "clean" fusion without neutrons, etc. This type of cold fusion is disputed - it shouldn't be possible within our current understanding of physics. It is also experimentally capricious, which is why the original experiments had a worldwide flurry of confirmations, then a flurry of retractions. People are still working on it, whether they're chasing gold at the end of the rainbow remains to be seen.


Third is sono-fusion, which is not cold fusion at all but hot fusion on a very small scale. It is supposed to work because of the high energy densities that are found in collapsing bubbles. A bubble has a surface energy, and if it collapses with spherical symmetry, this energy is concentrated into a smaller and smaller area. If the symmetry is maintained throughout the collapse the energy density would become infinite, but of course this doesn't happen. Collapsing bubbles can cause damage however - cavitation erosion of marine propellers for example.
It has been discovered that collapsing bubbles formed by sound waves emit flashes of light by an unknown mechanism, and these flashes imply momentary, very high temperatures. High enough for fusion? That is unconfirmed, but people are working on finding out. There have been claims of neutron detection and tritium production in deuterated acetone, but again the reproducibility is poor and the results are disputed.
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  #17  
Old 03-18-2005, 11:00 AM
Mathochist Mathochist is offline
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Quote:
Originally Posted by Avumede
From this interesting article at New Scientist:



New Scientist hints that cold fusion has been replicated, but doesn't actually come out and say it. Has it? Is there really good reason to think that cold fusion is real?
The coverage in SciAm was much clearer about the results: inconclusive.
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