Cosmic rays have a trick for traveling through space—they basically go 'ghost' to skip right through magnetic fields.
March 27, 2026
Original Paper
The 'Forgotten' Neutrons: Implications for the Propagation of High-Energy Cosmic Rays in Magnetized Astrophysical and Cosmological Structures
arXiv · 2603.25060
The Takeaway
Most cosmic rays are charged and get trapped by magnetic fields like balls in a pinball machine. This research shows they can escape these traps by transforming into neutrons, traveling in a straight line for huge distances where they shouldn't be able to go, and then turning back into protons.
From the abstract
Cosmological filaments, galaxy clusters, and galaxies are magnetized reservoirs of cosmic rays (CRs). The exchange of CRs across these structures is usually modeled assuming that they remain charged and magnetically confined. At high energies, hadronic interactions can convert CR protons to neutrons. This physics is routinely included in air-shower and ultra-high-energy (UHE) CR propagation Monte Carlo simulations used for composition studies but is rarely treated explicitly in propagation model