Thunderstorms Generate Mysterious 'Dark Lightning'

Have you ever heard of "dark lightning?"  Few people outside the scientific community have, but it is something real that is actually quite powerful - and possibly dangerous.  A group of scientists in Florida has been learning about this mysterious natural phenomenon:

We all know what thunderstorms are, and how much havoc their violent winds, torrential rains and lightning strikes can cause.  But over the past 10 years, scientists have learned of an even darker side to thunderstorms: they can generate powerful bursts of electromagnetic energy known as Terrestrial Gamma-Ray Flashes, or TGFs.
 
“A few years back, a spacecraft started seeing these bursts of gamma rays coming up from the Earth’s atmosphere," said Joseph Dwyer. "It was very strange.  The Earth is not supposed to make gamma rays.  If you want to study gamma rays you usually look for places like black holes and supernovas.  We figured out eventually that these gamma rays were coming from ordinary thunderstorms.”