Amaterasu Particle and Cosmic Ray Origins: 60-Year Mystery May Be Solved
Summary: The Amaterasu particle — the second most powerful cosmic ray ever detected — slammed into Earth in 2021 with the kinetic energy equivalent to a fast-moving tennis ball, yet appeared to originate from a void-like region of space with no known cosmic structures. New research suggests such ultrahigh-energy cosmic rays may actually be atomic nuclei of elements heavier than iron, potentially solving a 60-year-old mystery about what accelerates these particles to such extreme energies.