An international research team led by scientists from the Technion – Israel Institute of Technology has achieved the first direct measurement of cosmic rays deep inside a star-forming nebula. Using observations from the James Webb Space Telescope (JWST), the researchers detected the unique infrared signature produced when cosmic rays interact with molecular hydrogen at the core of Barnard 68, a cold, dense nebula located about 400 light-years from Earth. The study provides unprecedented insight into the behavior of cosmic rays far from the Solar System and their role in the earliest stages of star formation.

Cosmic rays—high-energy particles such as protons and atomic nuclei—play a critical role in regulating star birth by heating interstellar gas and driving chemical reactions that form key molecules, including water and ammonia. Until now, their properties inside star-forming clouds remained largely unknown. The new measurements confirm long-standing theoretical predictions and demonstrate that JWST can detect extremely faint infrared emissions generated by cosmic-ray–excited hydrogen, opening a new observational window on cosmic-ray astrophysics.

The findings, published in Nature Astronomy with complementary analysis in The Astrophysical Journal, pave the way for systematic mapping of cosmic rays across different galactic environments. With additional JWST observing time already approved, researchers aim to use nebulae as vast natural particle detectors to better understand how cosmic rays propagate through galaxies and influence the formation of stars like our Sun.