FASTBAUS FROM BLACK HOLES

摘要

A network of 1,400 ground-based particle detectors and two dozen telescopes has located the possible origin of the highest-energy cosmic rays. Traveling at near light speed, these rays—most likely protons—pack 10~(20) electron volts, 100 million times the energy produced by the largest particle accelerators and roughly equivalent to that of a fast-pitch baseball. The source appears to be nearby active galactic nuclei: bright galactic cores probably powered by supermas-sive black holes.