Illustration of an ultra-high-energy cosmic ray hitting Earth Osaka Metropolitan University/L-INSIGHT, Kyoto University/Ryuunosuke Takeshige
Astronomers have detected the second most powerful cosmic ray ever recorded, but it seems to have come from an empty region of the universe known as a cosmic void, where there is nothing obvious it could have originated from.
This mysterious cosmic ray, which is probably a charged particle nucleus of some variety, such as carbon or oxygen, has been dubbed Amaterasu after the Japanese sun goddess.
Possible explanations for it include magnetic fields steering the particle off-course, an invisible source in another galaxy or exotic…
