Polonium in the Earth's crust are not harmful. Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers. Because it is present in small concentrations, isolation of polonium from natural sources is a tedious process. The largest batch of the element ever extracted, performed in the first half of the 20th century, contained only (9 mg) of polonium-210 and was obtained by processing 37 tonnes of residues from radium production. Polonium is now usually obtained by irradiating bismuth with high-energy neutrons or protons. In 1934, an experiment showed that when natural Bi is bombarded with neutrons, Bi
The Apocalypse Element galaxy. The Apocalypse Element The Apocalypse Element is a Big Finish Productions audio drama based on the long-running British science fiction television series "Doctor Who". It forms the second serial in the Dalek Empire arc, following on from events in "The Genocide Machine". The arc continues in "The Mutant Phase" and concludes in "The Time of the Daleks". At a conference on Archetryx between major temporal powers, the Sixth Doctor and Evelyn discover that Romana has been missing for twenty years and that the Daleks' newest weapon — the Apocalypse Element — threatens not only the Time Lords but the