Science News

Thunderstorm Accelerators

Scientists in Japan have discovered that thunderstorms act as huge particle accelerators. Harafumi Tsuchita of Japan's RIKEN research institute and collegues installed a directional gamma ray detector at a nuclear power plant. Recently this picked up a 40 second burst of high energy gamma rays. These had a frequency 40 million times higher than normal light. By looking at the spectrum of these gamma rays, it looks as though they are being emitted by electrons that are accelerated to nearly the speed of light by the huge voltages before a lightening strike and then suddenly stopping when they hit an atom. All their energy is then released as gamma rays. They knew it was definitely coming from the thunderstorm because the detector is directional and there was a thunderstorm in the direction the gamma rays were coming from.

Shorter bursts from thunderstorms have been accidently detected in the past by space based telescopes which were built to detect Gamma Ray Bursters in outer space. But this is the first time such a long burst has been detected and that it has been definitely tied down to a thunderstorm.

23rd Sep 2007