Antimatter spews into space from terrestrial thunderclouds

BBC : The intense electric fields that give rise to lightning strikes and thunderclaps also impart so much energy to atmospheric electrons that the electrons trigger flashes of gamma rays when they slam into atoms and molecules. Astronomers knew about those terrestrial gamma-ray flashes. What has come as a surprise is that the gamma rays spontaneously convert into pairs of electrons and positrons (antielectrons). Speaking yesterday at the meeting of the American Astronomical Society in Seattle, Washington, Julie McEnery described how the Fermi Gamma-Ray Space Telescope made the unexpected discovery.