For years, astronomers have searched for the origins of ultra-high-energy cosmic rays ... particles were coming from billions of light-years away, they would gradually slow down due to ...

Cosmic rays are particles from outer space that travel ... In the next century and a half, scientists narrowed this down. They knew there was some source of radiation that occasionally interacted with ...

The open sky was an unfamiliar sight. "Surreal," he said. The Rays would have to find a new ... "When the sun goes down, some say the ball doesn't carry as much as other times here," Cash said.