of the highest energy cosmic rays interacting with the cosmic microwave background and the universe becoming opaque to their propagation. In 2010 final results of the HiRes experiment confirmed the GZK cutoff. A follow-on experiment to the High Resolution Fly's Eye and Akeno Giant Air Shower Array (AGASA) experiments is the Telescope Array Project which began data collection in central Utah in 2007. A similar approach, but with the water-Cherenkov detectors, has been employed for the Pierre Auger Observatory which began collecting data in 2004. Awards Dr. Pierre Sokolsky and Dr. George Cassidy, both of the University of Utah, received the 2007 Panofsky Prize for their work on the HiRes experiment. See also List of astronomical observatories References External links High energy particle telescopes Cosmic-ray experiments University of Utah Buildings and structures in Tooele County, Utah Astronomical observatories in Utah