Gamma rays are the highest-energy photons, emitted from radioactive decay, nuclear explosions and massive hypernova collapses of stars. But these packets of energetic havoc are also formed, albief briefly and weakly, by lightning. Satellites had previously observed these bursts, called Terrestrial Gamma Ray Flashes, in upward-propagating lightning high above the surface of the earth, in the lower stratosphere, lasting only a few milliseconds. Now, using the U’s Telescope Array, a cosmic ray detector in west-central Utah, scientists have observed gamma ray flashes triggered by lightning that often reached the ground. The flashes are short, only a few microseconds, but show that lightning’s high energy can generate more than just a flash and bang. U physicist John Belz will present on this topic at the American Geophysical Union fall meeting on Dec. 13.
John Belz | 801-585-9620 | belz@physics.utah.edu