Representation of a cosmic ray hitting the earth, with a showering cascade of particles branching out from an initial impact.

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1. Robert McNees (mcnees@mastodon.social)'s status on Sunday, 15-Oct-2023 15:20:53 UTC Robert McNees

   The most energetic single particle ever detected, a cosmic ray dubbed the "Oh-My-God" particle, was observed by the Fly's Eye Cosmic Ray Detector #OTD in 1991.

   Its energy was about 3.2 x 10²⁰ eV ~ 51 J, equivalent to a baseball moving at almost 60 mph.

   https://www.quantamagazine.org/the-particle-that-broke-a-cosmic-speed-limit-20150514/

   Image: Olena Shmahalo/Quanta Magazine, using images of the Earth from NASA.