James Cronin and University of Leeds professor Alan Watson lead an international project to study the nature and origin of rare but extremely powerful, high-energy (>1019 eV), cosmic rays that periodically bombard Earth. The project includes more than 250 scientists from nineteen nations.

The scientists will practice a new form of astronomy rooted in particle physics. Construction of the Pierre Auger Observatory, a giant detector array near the cities of Malargue and San Rafael in Argentina's Mendoza Province, will be completed by 2003, but researchers plan to begin observations as early as 2001. The site will contain 1600 particle detection stations 1.5 kilometers apart, arranged in a giant grid covering 3000 square kilometers, an area about the size of the state of Rhode Island. The Auger Project collaborators hope later to construct a complementary northern hemisphere observatory which, together with the southern observatory, would allow studies of cosmic rays from the entire sky.