GAMMA-RAY AND X-RAY events above thunderstorms are the most puzzling of all high-altitude electrical phenomena. Their existence was uncovered only recently by one of the instruments on the Compton Gamma Ray Observatory satellite (below), which showed gamma rays emanating from the direction of the earth. Gamma rays are usually taken as signatures of high-energy nuclear or cosmic sources and thus were not expected to be produced within the earth's atmosphere. In sprites, for example, electrons rarely reach energies above about 20 electron volts (the energy a single electron would gain when accelerated by a potential difference of 20 volts), whereas gamma rays require about one million electron volts. The discrepancy is the same as the difference between the energy of a chemical explosive and an atomic bomb. As is the case with blue jets, gamma-ray events are just now beginning to yield to scientific scrutiny. Future observations from satellites should help in this quest.

gamma rays


Image: Bryan Christie