Submission + - highest energy cosmic rays explained
An anonymous reader writes: Sci-fi author and astrophysicist Gregory Benford has a new theory about what accelerates some cosmic rays to nearly the speed of light. These ultra-high-energy cosmic rays have mystified scientists because they should interact with cosmic microwave background photons in space, losing energy before they get to Earth. Now, Benford and collaborator Raymond Protheroe say decaying magnetic fields around galaxies whose central black holes have shut down can boost cosmic rays to extreme speeds. That means astronomers don't have to resort to exotic theories about dark matter and defects in space-time to explain the high-energy particles. "Given what we know now, I think [decaying magnetic fields] are the least implausible explanation," Stanford's Roger Blandford enthuses.
