The most powerful cosmic ray since the Oh-My-God particle puzzles scientists ( www.nature.com )
Scientists have detected the most powerful cosmic ray seen in more than three decades. But the exact origin of this turbocharged particle from outer space remains a mystery, with some suggesting that it could have been generated by unknown physics.
The puzzling cosmic ray had an estimated energy of 240 exa-electronvolts (EeV; 10^18^ electronvolts)
