New satellite observations of terrestrial gamma-ray flashes reveal surprising features of mysterious blasts from Earth

A particle accelerator operates in Earth's upper atmosphere above major thunderstorms at energies comparable to some of the most exotic environments in the universe, according to new satellite observations of terrestrial gamma-ray flashes.
Terrestrial gamma-ray flashes (TGFs) are very short blasts of gamma rays, lasting about one millisecond, that are emitted into space from Earth's upper atmosphere. The gamma rays are thought to be emitted by electrons traveling at near the speed of light when they scatter off of atoms and decelerate in the upper atmosphere. TGFs were first discovered in 1994 by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory.