Cold fusion is sort of like the alchemy of the modern world - yes, there might be a trickle of real science behind it, but the idea that it could provide free, limitless energy is almost certainly a pipe dream. Cold fusion became infamous in the late 1980s with the extremely controversial and largely rejected findings of Stanley Pons and Martin Fleischmann, and since then cold fusion has largely gone from legitimate line of inquiry to the domain of cranks, laughingstocks and hoaxers. For more background on cold fusion, check out this post from last year.
That more or less brings us to today, as physicists Andrea Rossi and Sergio Focardi of Italy's University of Bologna have unveiled their supposed massive breakthrough. They don't just claim to have figured out how to make a cold fusion reactor, the actually say that they have built one and already tested it, with lots of new reactors ready to ship within the next few months.
Before you get out your checkbook, let's examine what's going on here. The scientists claim that a reactor has been running a factory for the last two years, but nobody knows what they're talking about and the physicists did not elaborate on where or what this factory is.
They also don't have any theoretical foundation for their work. They say the reactor takes in nickel and hydrogen, and then it produces copper and tons of energy, all at room temperature. But they admit they don't know how any of that is going on, and there's a ton of theoretical work that says reactions don't work in the way the pair have described. It's not impossible for an empirical discovery to precede the theoretical understanding, but in this case it's an excellent reason to be very skeptical, if not outright dismissive.
The scientific community definitely wants nothing to do with their work, as Rossi and Focardi have had to create their own journal, the Journal of Nuclear Physics, just to get their scientific paper published. The European Patent Office has also pretty much rejected it out of hand, as a preliminary report explains:
"As the invention seems, at least at first, to offend against the generally accepted laws of physics and established theories, the disclosure should be detailed enough to prove to a skilled person conversant with mainstream science and technology that the invention is indeed feasible. … In the present case, the invention does not provide experimental evidence (nor any firm theoretical basis) which would enable the skilled person to assess the viability of the invention. The description is essentially based on general statement and speculations which are not apt to provide a clear and exhaustive technical teaching."
Indeed, even the internet - which just last week managed to conflate the Betelgeuse supernova with 2012 prophecies - doesn't seem to want any part of this. Cold fusion is, if not outright impossible, then certainly highly implausible. If - and that's a big if - cold fusion ever does become a legitimate field of inquiry, it will likely come in several small incremental stages, as scientists first work out how such reactions could even work in the first place. The future of human energy is unlikely to come in the form of self-published scientific papers and vague pronouncements about a factory.
Still, co-discoverer Andrea Rossi deserves a chance to mount a rebuttal:
"We have passed already the phase to convince somebody. We are arrived to a product that is ready for the market. Our judge is the market. In this field the phase of the competition in the field of theories, hypothesis, conjectures etc etc is over. The competition is in the market. If somebody has a valid technology, he has not to convince people by chattering, he has to make a reactor that work and go to sell it, as we are doing."
So, there you have it. We'll know what's the deal with these cold fusion reactors in three months. I'm pretty sure we know what's going on already, but I suppose there's nothing wrong with keeping an open mind... just a highly sceptical one.