In 1991, scientists discovered the so-called "dark lightning." It was found that when at the height of 5000 meters, the plane is covered by a zipper, all passengers and crew members can get a dose of gamma radiation, equates to 10 years of natural background.
Dark Lightning - a stream of electrons moving with nearly the speed of light. In the reaction with oxygen molecules, gamma rays occur. They generate electrons and positrons, which mixes with air to form a still greater number of gamma rays.
The scientific world was that the appearance of lightning - a fairly rare phenomenon, occurring no more than a few thousand times a year. Recently, however, the Norwegian scientists have come to believe that the dark lightning directly related to conventional lightning. The researchers considered such a thing as an intermediate step of forming a storm of electrical discharges. Atmospheric emission of gamma rays dark lightning leads to a strong radio pulses, a white lightning, which can be observed during thunderstorms.
These conclusions were Norwegian, by observing a section of the atmosphere. The study authors found a correlation between the dark lightning and radio pulse recorded in the same time at a fairly remote distance from the epicenter of the storm.
A new concept assumes that the first electrical discharge leads to a gamma-ray burst, then the electrons drawn by such a discharge, provoke a radar pulse, and this, in turn, causes the classic electric discharge. Thanks to this discovery, the Norwegians have put forward the hypothesis that the process of formation of dark lightning is far more common than previously thought. However, to come to final conclusions should conduct additional research.