At five o’clock on Tuesday morning, Yasser Arafat’s body was disinterred in Ramallah and tissue samples extracted for analysis by French, Swiss and Russian scientists. One of the things they’ll be testing for is polonium poisoning. But can a meaningful result be hoped for eight years after Arafat’s death? The half-life of Po-210 in vacuo is 138 days (i.e. half the original Po-210 nuclei would decay on average in 138 days) but in the body it’s rather less, between two and three months (i.e. on average half the Po-210 atoms would have passed through the body after this time). Either way, a definitive result for Arafat would be difficult to obtain now, since after eight years the initial quantities of any Po-210 would be diluted by a factor of a million. As a spokesperson for the University of Lausanne's Institute of Radiation Physics has said, the traces of polonium they found on Arafat's clothes a few months ago could be a more recent contamination and don't prove anything.