Cold Fusion was first reported in 1989. The original experiment was supposed to have produced extra heat that could not be explained wiht chemistry or electronics, so naturally, fusion was considered. Contrary to popular belief, that original experiment has been replicated successfully. The problem isn’t that the first experiment produced actual extra heat and no one doing the same experiment could match that result. Rather, none of the attempts at using this experimental set up worked, including the first one. So, yes, the experiment was successfully replicated, and in all cases, nothing happened.
The bits and pieces that would have been relevant to cold fusion had it existed have been used and reused in a small, but global, cottage industry of cold fusion experimenters, since the original experiment and continuing to today. Very little cold fusion work since the first Fleischmann–Pons experiments has followed those original protocols, and in fact, they are quite different experiments, often looking for very different things. It is a little like this: Someone claims that Bigfoot lives in a certain forest. So, lots of people show up to find Bigfoot. Over a period of a year or so everyone realizes that the Bigfoot claim was bogus. But, there are still people looking in the forest, and some of them come back with blurry pictures of what they claim is Chupacabra. Someone else finds that the lake in the forest has mermaids, but again, the photos are blurry. And so on.
I’m mostly glad they have been doing this research though. The possibility of a “nuclear” kind of thing happening with basic chemistry is too important to totally write off just because, well, there is no evidence for it. As long as a) the total budget for this research stays below 0.00001% of the total physics and chemistry research budget for the world, and b) after a while we just stop looking if nothing is found, then that’s OK.
THEY SAID GALILEO WAS WRONG AFTER ALL!!!
Unfortunately, while condition A has been met, condition B has not. They should probably stop now.
Anyway here’s an interesting story. I remember when Cold Fusion was a thing, and I remember how stridently the anti-cold fusion masses swarmed Pons and Flieishman and how unequivocally they were driven into the swamp. The whole idea of stuff that can only happen in a nuclear reactor or inside a star being done in a test tube was outrageous! We’ve finally gotten over that; we now know that tiny theoretical black holes are forming all the time in the upper atmosphere because of cosmic rays running into our earthly molecules, for example. (And people probably knew that back then. If it is true.) The point is, if someone came along within a short time after the initial unveiling and rapid beheading of Cold Fusion with anything that looked even a little like nuclear physics happening in a setting where chemists (or any other scientists) operate, stern looks ensued.
So, in 1991, when the open festering wound of cold fusion was just starting to scar over, an interesting observation was made. Previously, it had been noticed by spy planes, astronauts, etc. (people who were really really high) that blue streaks or flashes would sometimes come flying out of the tops of the larger thunder heads. In 1991 someone flying over a storm system with a gamma ray detector picked up gamma rays flying out of the clouds. As I remember this, it was in association with blue flashes. I also remember the observation being treated gingerly. Reactions from “Oh, interesting, someone should look at that maybe” to “Well, obviously you can’t get gamma rays from lightning, that’s impossible, but well, whatever, cold fusion ugh” were to be found at that time.
Since then, slowly but surely, the gamma ray bursts have been observed and confirmed and it is real. It turns out that this happens because a particularly energetic bit of lightning totally wastes some atoms and gamma rays come flying out (upwards, mainly). Indeed, if Pons and Fleishman had produced a small amount of extra heat after ablating some matter with a giant laser, that may have been believable. (but it would not have been cold, so who cares?) These gamma rays, coming out of the clouds, are not cold fusion. They are high energy reactions to high energy actions.
Anyway, there is some new research on the gamma rays that you might be interested in. Here’s the abstract:
We present the very first simultaneous detection from space of a terrestrial gamma ray flash (TGF) and the optical signal from lightning. By fortuitous coincidence, two independent satellites passed less than 300 km from the thunderstorm system that produced a TGF that lasted 70? ?s. Together with two independent measurements of radio emissions, we have an unprecedented coverage of the event. We find that the TGF was produced deep in the thundercloud at the initial stage of an intracloud (IC) lightning before the leader reached the cloud top and extended horizontally. A strong radio pulse was produced by the TGF itself. This is the first time the sequence of radio pulses, TGF, and optical emissions in an IC lightning flash has been identified.
The important finding here is that the lightning bolt that makes the gamma ray is ginormous and propagates from a very low altitude compared to what they were previously assuming.
There is also a write-up that I think is not behind a paywall HERE.
First thought to be generated at high altitudes, researchers have recently pinned down the origin of the fleeting lightning-linked bursts—one of the most energetic surges of natural electromagnetic radiation on Earth—to altitudes below 20 kilometers, in the layer of the atmosphere where most weather happens.
If only we could harness this energy!
Østgaard, N., Gjesteland, T., Carlson, B., Collier, A., Cummer, S., Lu, G., & Christian, H. (2013). Simultaneous observations of optical lightning and terrestrial gamma ray flash from space Geophysical Research Letters DOI: 10.1002/grl.50466