Number 289 (Story #1), October 3, 1996 by Phillip F. Schewe and Ben Stein TeV-ENERGY GAMMA BURSTS from the galaxy Markarian 421, observed in May 1996, constitute the largest, purest flux of very high energy gamma rays yet recorded for an astronomical object. In one burst the flux increased above quiescent levels by a factor of 50 in an hour. A second burst 8 days later lasted only 30 minutes. The potency and brevity of such bursts (suggesting a source no larger than our solar system) provide new constraints on theories of energetic emissions from compact objects. The bursts were detected at the Whipple Observatory in Arizona, where air showers initiated by the incoming gammas show up as light in Cerenkov counters. (J.A. Gaidos et al., Nature, 26 September 1996.)