The 'Oh-My-God' Particle
In 1991, a detector in the Utah desert caught a single particle from space carrying as much energy as a fast-thrown baseball. No one knows what could have launched it.
What was reported
On the night of 15 October 1991, the Fly's Eye detector, in the desert of western Utah, recorded a cosmic ray, a particle from space hitting the atmosphere, with an energy far beyond anything thought possible. A single subatomic particle, probably a proton, was carrying about as much energy as a baseball thrown at around 90 kilometres an hour.
Physicists nicknamed it the 'Oh-My-God particle'. Since then, other detectors have found a few similar particles, including one called Amaterasu in 2021.
Explanations offered
No known object in our part of the universe seems powerful enough to accelerate a particle to such energy, and particles that energetic shouldn't be able to travel far through space without losing energy. Where they come from is one of the great puzzles of physics.
- When
- 15 October 1991
- Where
- Dugway Proving Ground, Utah, USA
- Witnesses
- The Fly's Eye cosmic ray detector
- Status
- Unexplained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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