A MYSTERIOUS property of lightning has been confirmed. Just before a flash of lightning lights the sky, a huge blast of X-rays or other high-energy particles is released. The phenomenon means physicists may have to rethink how lightning is made.
Past studies of lightning have seen occasional hints of X-ray bursts, but the signals were swamped by the electromagnetic noise that accompanies lightning. So space physicist Joseph Dwyer at the Florida Institute of Technology and his colleagues set up a scintillation detector in a field in Florida, where in the summer thunderstorms happen daily. An aluminium box with centimetre-thick walls…
