'Dark lightning' zaps airline passengers with radiation[ Wed, 10 Apr 2013 16:02:57 GMT ]By Charles ChoiLiveScience "Dark lightning" that is almost invisible within clouds may regularly blast airline passengers with large numbers of gamma rays, scientists find.However, these outbursts do not seem to reach truly dangerous levels, researchers added.More than a decade ago, researchers unexpectedly discovered thunderstorms could generate brief but powerful bursts of gamma rays, the highes...