Stephen Thorsett of Princeton University estimates that gamma ray bursts caused, for instance, by the merging of neutron stars, could, if they occurred within a couple of hundred light years of the Earth, expose the atmosphere to as many gamma rays as the detonation of all the planet's nuclear weapons. The ozone layer would disappear for several years, allowing deadly ultraviolet radiation to reach the Earth's surface, causing mass extinctions. Thorsett estimates that gamma ray bursts within lethal range of Earth will occur once every few hundred million years.
The Compton Gamma Ray Observatory detects more distant such bursts on a daily basis - its telescope may be recording the death of a far-off civilization on an Earth-like planet.
Previous / Next / Table of Contents