Although cosmic rays were discovered 100 years ago, their origin remains one of the most enduring mysteries in physics. Now, the IceCube Neutrino Observatory, a massive detector in Antarctica, is honing in on how the highest energy cosmic rays are produced. "Although we have not discovered where cosmic rays come from, we have taken a major step towards ruling out one of the leading predictions," said IceCube principal investigator and University of Wisconsin - Madison physics professor Francis Halzen.

In a paper recently published in Science Express, cosmic ray data from IceCube was used alongside observations from NASA's Interstellar Boundary Explorer, or IBEX, in a study of the magnetic fields that surround our solar system.