Atoms consist of a positive nucleus and negative electrons flying around outside it. Electrons closest to the nucleus feel a strong negative-on-positive tug, and the bigger atoms get, the bigger the tug. In really big atoms, electrons whip around at speeds close to the speed of light.
More Sam Kean quotes :
Something funny certainly happens when palladium and platinum come into contact with hydrogen gas; it's one of the great mysteries still waiting to be solved on the periodic table. But it's quite a leap from 'something funny' to cold fusion.Sam Kean