The "Oh-My-God particle", an ultra-high-energy cosmic ray measured at 40,000,000 times that of the highest energy protons produced in a particle accelerator, is observed at the University of Utah HiRes observatory in Dugway Proving Ground, Utah.

The Oh-My-God particle (as physicists dubbed it) was an ultra-high-energy cosmic ray detected on 15 October 1991 by the Fly's Eye camera in Dugway Proving Ground, Utah, United States. As of 2023, it is the highest-energy cosmic ray ever observed. Its energy was estimated as (3.2±0.9)×10²⁰ eV (320 exa-eV). The particle's energy was unexpected and called into question prevailing theories about the origin and propagation of cosmic rays.

In astroparticle physics, an ultra-high-energy cosmic ray (UHECR) is a cosmic ray with an energy greater than 1 EeV (10¹⁸ electronvolts, approximately 0.16 joules), far beyond both the rest mass and energies typical of other cosmic ray particles. The origin of these highest energy cosmic rays is not known.

A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies to contain them in well-defined beams. Small accelerators are used for fundamental research in particle physics. Accelerators are also used as synchrotron light sources for the study of condensed matter physics. Smaller particle accelerators are used in a wide variety of applications, including particle therapy for oncological purposes, radioisotope production for medical diagnostics, ion implanters for the manufacturing of semiconductors, and accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.

The University of Utah is a public research university in Salt Lake City, Utah, United States. It was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest institution of higher education. The university received its current name in 1892, four years before Utah attained statehood, and moved to its current location in 1900. It is the flagship university of the Utah System of Higher Education.