The Oh-My-God particle was a really tiny portion of matter or energy (undefined) moving incredibly fast. It was first spotted on the evening of 15 October 1991 over Dugway Proving Ground in Utah and shocked many astrophysicists. It has an estimated energy of (50 J)—in other words, a subatomic particle with kinetic energy equal to that of a baseball () traveling at about . That amount of energy is also 50 times the energy that a collision in the Large Hadron Collider would have.