Researchers at the Pierre Auger Observatory, a complex of detectors spread over a Rhode Island-sized slice of the South American prairie, said the most likely source for these ultra-high-energy particles is a type of black hole found at the center of some galaxies.
These violent phenomena are called active galactic nuclei because they both gobble up energy from the surrounding space and spit some out with tremendous force.
"This is a fundamental discovery. We have taken a big step forward in solving the mystery of the nature and origin of the highest-energy cosmic rays," said Nobel laureate James Cronin, a professor emeritus at the University of Chicago and coauthor of the paper published in the current issue of the journal Science.
Cosmic rays are charged particles that can strike with the force of a thrown baseball. Fortunately for humans, Earth's atmosphere serves as a shield, preventing the particles from reaching the surface. Link