One of the great scientific mistakes of the century, cold fusion occured when two researchers doing fusion research decided to try a different approach, instead of standard "hot" fusion,such as what occurs inside the sun, they tried simpply adding palladium metal to sea water, which was supposed to emit neutrons so fusion occurred when an electric current was run through the mixture. They claimed that during this procedure they recorded huge temperature rises, and enough neutrons given off to make them believe they had created fusion at room temperature. This discovery caused a worldwide sensation, but as scientists tried to repeat the experiment, they found no conclusive results, and the researchers were discredited, and cold fusion abandoned.

Update on 3/11/02: over the last few weeks a new group of researchers have claimed that they detected signs of cold fusion in imploding bubbles in acetone, a phenomena theoretically capable of creating the temperatures and pressures required for fusion. These results are not yet confirmed Update: these results have proved to be impossible to replicate