The Pierre Auger Observatory is the world’s largest cosmic-ray detector, aimed at the study of the most energetic particles in the Universe. These are extremely rare particles with energies from 1018eV to 1020eV and beyond (a billion to a trillion times the energy stored in the mass of a proton). How Nature accelerates particles to such enormous energies is still a mystery. To detect them with good statistical precision, physicists from 17 countries are deploying 1600 detectors (water Cherenkov counters) over a 3000km2 area of Western Mendoza Province, Argentina, as well as 24 nitrogen fluorescence telescopes that look at the sky over the large ground array on dark, moonless nights. Another similar array of detectors is planned for deployment in Colorado. Penn State faculty Stephane Coutu and Paul Sommers are involved in the project, with Sommers serving as Co-Spokesman of the international Auger Collaboration. For more information, see the official Auger Web site. You can also explore the Auger Observatory using Google Earth.