The "Oh-My-God particle" refers to an extremely high-energy cosmic ray particle that was detected in 1991. Specifically, it was observed by the Fly's Eye observatory in Utah, USA. This particle, with an energy of about 3.2 x 10²⁰ electronvolts (eV), is significantly more energetic than any particles produced in terrestrial particle accelerators, such as the Large Hadron Collider.
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