Ultrahigh-energy cosmic messengers may carry ultraheavy secrets

There may be an ultraheavy explanation for the mystery surrounding the origins of the highest-energy particles ever observed. Ultrahigh-energy cosmic rays are particles from space that strike Earth with energies far beyond those reachable by human-made particle accelerators. One of the most extreme events ever recorded is the “Amaterasu particle,” detected by the Telescope Array in Utah in 2021 and named after the sun goddess in Japanese mythology. Its reported energy places it among the highest-energy cosmic-ray events ever observed, comparable to the “Oh-My-God particle” detected in 1991, yet its origin—and even its identity—remain uncertain.