<P> Rutherford and Soddy were observing natural transmutation as a part of radioactive decay of the alpha decay type . However, in 1919, Rutherford was able to accomplish transmutation of nitrogen into oxygen, using alpha particles directed at nitrogen N + α → O + p . This was the first observation of a nuclear reaction, that is, a reaction in which particles from one decay are used to transform another atomic nucleus . In 1932, a fully artificial nuclear reaction and nuclear transmutation was achieved by Rutherford's colleagues John Cockcroft and Ernest Walton, who used artificially accelerated protons against lithium - 7 to split the nucleus into two alpha particles . The feat was popularly known as "splitting the atom," although it was not the modern nuclear fission reaction discovered in 1938 by Otto Hahn, Lise Meitner and their assistant Fritz Strassmann in heavy elements . </P> <P> Later in the twentieth century the transmutation of elements within stars was elaborated, accounting for the relative abundance of heavier elements in the universe . Save for the first five elements, which were produced in the Big Bang and other cosmic ray processes, stellar nucleosynthesis accounted for the abundance of all elements heavier than boron . In their 1957 paper Synthesis of the Elements in Stars, William Alfred Fowler, Margaret Burbidge, Geoffrey Burbidge, and Fred Hoyle explained how the abundances of essentially all but the lightest chemical elements could be explained by the process of nucleosynthesis in stars . </P> <P> It transpired that, under true nuclear transmutation, it is far easier to turn gold into lead than the reverse reaction, which was the one the alchemists had ardently pursued . Nuclear experiments have successfully transmuted lead into gold, but the expense far exceeds any gain . It would be easier to convert lead into gold via neutron capture and beta decay by leaving lead in a nuclear reactor for a long period of time . </P> <P> Glenn Seaborg produced several thousand atoms of gold from bismuth, but at a net loss . </P>

What would need to happen to change a lead atom into a gold atom