Space scientists seeking to understand the enigmatic origins of powerful cosmic rays have detected an extremely rare, ultra-high-energy particle that they believe traveled to Earth from beyond the Milky Way galaxy.
The energy of this subatomic particle, invisible to the naked eye, is equivalent to dropping a brick on your toe from waist height, according to the authors of new research published Thursday in the journal Science. It rivals the single most energetic cosmic ray ever observed, the “Oh-My-God” particle that was detected in 1991, the study found.
Cosmic rays are charged particles that travel through space and rain down on Earth constantly. Low-energy cosmic rays can emanate from the sun, but extremely high-energy ones are exceptional. They are thought to travel to Earth from other galaxies and extragalactic sources.
“If you hold out your hand, one (cosmic ray) goes through the palm of your hand every second, but those are really low-energy things,” said study coauthor John Matthews, a research professor at the University of Utah.
“When you get out to these really high-energy (cosmic rays), it’s more like one per square kilometer per century. It’s never going through your hand.”
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