Comment Re:More important: how is this happening? (Score 1) 70
Unfortunately, TFA doesn't suggest the question. Gamma bursts were not expected on Earth because they are created by nuclear interactions. Common for stars and other cosmic objects but not expected in thunderstorms. The source could be electrical, which means they are technically x-rays but at a higher energy then thought possible. Alternatively, there is significant nuclear fusion going on in those storms.
Actually gamma-rays are very common on earth. In fact, a common geophysical method of exploration called airborne gamma-ray spectrometry (sometimes called radiometrics) is widely used for regional mapping and mineral exploration. One of the corrections applied to this data is the removal of the cosmic component. The cosmic gamma-rays have greater energies than those from the decay of naturally occurring potassium, uranium, and thorium in rocks and soil.
The article just says gamma bursts, but they must mean high-energy gamma bursts.