In a cosmic revelation reminiscent of the iconic “Oh-My-God” particle discovery in 1991, physicists have identified a new particle with extraordinary energy, challenging our understanding of cosmic phenomena. Published in the November 24 issue of Science, the particle, detected in 2021 near Delta, Utah, boasts an energy level of approximately 240 exaelectron volts.
Astroparticle physicist John Matthews, co-spokesperson of the Telescope Array collaboration at the University of Utah, describes the find as a “huge amount of energy in a tiny object.” This revelation follows the 1991 discovery of a particle with 320 quintillion electron volts, generating an “OMG!” reaction from scientists.
The rarity of such high-energy particles adds to their intrigue. These cosmic rays, composed of protons and atomic nuclei, travel through space at varying energies. Those exceeding 100 exaelectron volts are exceptionally rare, with an estimated occurrence of just one per square kilometer of Earth’s surface each century. The newly identified particle, with over 200 exaelectron volts, falls into an even more exclusive category.
Scientists employ large arrays of detectors to capture these elusive particles. The Telescope Array, covering 700 square kilometers with over 500 scintillator detectors, observes cascades of particles created when cosmic rays collide with atmospheric nuclei. By analyzing the arrival times and directions of these particles, scientists trace their origin back to the depths of space.
While high-energy cosmic rays are believed to originate outside our Milky Way, their precise sources remain elusive. The current consensus suggests acceleration in violent cosmic environments, such as radiation jets near supermassive black holes or in starburst galaxies producing stars at an intense rate.
The challenge lies in backtracking these particles to their origins, complicated by the scattering effect of magnetic fields in the Milky Way. Noémie Globus, an astroparticle physicist at the University of California, Santa Cruz, notes that high-energy cosmic rays’ arrival directions are deflected by these magnetic fields, adding complexity to pinpointing their source.
Intriguingly, the recent discovery points to a cosmic void, an area with minimal galaxies and seemingly devoid of violent cosmic processes. Astrophysicist Vasiliki Pavlidou of the University of Crete emphasizes the particle’s significance, noting that it “points towards nothing at all, absolutely in the middle of nowhere.” This anomaly raises questions about our understanding of magnetic fields and suggests potential gaps in current scientific knowledge.
The unveiling of such high-energy cosmic events remains a monumental occasion, prompting scientists to delve deeper into the mysteries of the universe.
