Utah Detector Recorded 3.2×10²⁰ eV Cosmic Ray, Leaving Its Source Unknown
Updated
Updated · Boing Boing · Jul 22
Utah Detector Recorded 3.2×10²⁰ eV Cosmic Ray, Leaving Its Source Unknown
1 articles · Updated · Boing Boing · Jul 22
Summary
A University of Utah detector logged a single cosmic ray at about 3.2×10²⁰ electronvolts on Oct. 15, 1991, an energy so extreme physicists dubbed it the “Oh-My-God particle.”
That particle carried roughly the kinetic energy of a baseball moving 100 kilometers per hour and about 40 million times the energy of the most powerful accelerator-made protons on Earth.
At least 15 similar events have since been recorded, confirming ultra-high-energy cosmic rays are real but exceptionally rare; the Pierre Auger Observatory sees about one above the top thresholds every four weeks.
Their origin remains unresolved: they do not track the Milky Way’s plane, and galactic magnetic fields appear too weak to accelerate them, pointing instead to extragalactic sources such as magnetars or active galactic nuclei.
Are the universe's fastest particles not protons, but super-heavy atoms from dead stars?
A 'chirping' supernova just revealed a newborn magnetar. Is this the key to a 35-year-old cosmic mystery?
The Amaterasu Particle and the Ultra-High-Energy Cosmic Ray Mystery: Unraveling the Origins of 240 EeV Events
Overview
In 2021, the Telescope Array in Utah discovered the Amaterasu particle, an ultra-high-energy cosmic ray with an energy of 240 EeV. Named by Professor Fujii and his team after the Japanese sun goddess, this particle joins the ranks of the most powerful cosmic rays ever detected, alongside the famous Oh-My-God particle. The discovery was made by analyzing existing data from a vast network of detectors. This event adds a new chapter to the ongoing mystery of ultra-high-energy cosmic rays, challenging scientists to uncover their origins and understand the extreme processes that create such energetic particles.