Cold Fusion

Cold fusion is the hypothesis that a nuclear fusion reaction could occur at or near room temperature, in contrast to the extreme temperatures fusion requires inside stars, hydrogen bombs or experimental fusion reactors. The claim entered public attention in 1989 when University of Utah electrochemists Martin Fleischmann and Stanley Pons reported that a tabletop apparatus electrolyzing heavy water at a palladium electrode produced excess heat, along with trace neutrons and tritium, results they said pointed to a nuclear rather than a chemical cause. Numerous attempts to replicate the experiment failed, previously reported positive replications were retracted, and methodological flaws in the original work were identified, so that by late 1989 most scientists regarded the cold fusion claim as refuted; the United States Department of Energy reviewed the evidence in 1989 and again in 2004 and both times declined to fund cold fusion research. A small community of researchers has continued investigating the phenomenon since, often under the alternate names low energy nuclear reactions or condensed matter nuclear science, though a Google funded replication attempt published in Nature in 2019 also failed.