Feb. 14, 2025 — More than a century ago, scientists pondered how evolution might be driven by mutations caused in part by cosmic rays that bombard Earth after the explosive demise of faraway stars. Yet how cosmic rays move through space has been an open question in astrophysics for decades.
Cosmic rays are atoms stripped down to their nuclei and accelerated by stars, supernovae, black holes and galactic collisions. They are sparse…