Scientists of the Pierre Auger Observatory in Argentina announced that Active Galactic Nuclei (AGN) are the most likely candidates for the source of the highest-energy cosmic rays that hit Earth. A team of scientists from 17 countries found that the sources of the highest-energy particles are not distributed uniformly across the sky. Instead, the Auger results link the origins of these mysterious particles to the locations of nearby galaxies that have active nuclei in their centers. The Pierre Auger Observatory, the largest cosmic-ray observatory in the world, has been collecting data since early 2004.