Nuclear Reactions in the Atmosphere

Physicists have seen radioactive isotopes being created naturally in the atmosphere before, but only when atoms are hit by hinegy particles whizzing in from outer space. Teraaki and his colleagues think that the initial gama rays were powerful enough to kick neutrons out of some atoms in the atmosphere leaving them unstable and radioactive. Shortly after these neutrons were produced, these radioactive atoms would decay, spitting out positrons,. These positrons annihilate with electrons in the atmosphere, creating the signal that was seen.