Technion-led team makes first direct measurement of cosmic rays in a star-forming cloud

Astronomers led by Dr. Shmuel Bialy of the Technion – Israel Institute of Technology have for the first time directly measured cosmic rays inside a cold cloud of gas and dust where stars are born. Their paper, Direct detection of cosmic-ray-excited H2 in interstellar space, was published in Nature Astronomy on 3 February 2026, and the Technion announced the result the following day. Co-authors include Bialy's master's student Amit Chemke and Prof. David Neufeld of Johns Hopkins University, among an international team of about 16 researchers.

Cosmic rays are high-energy particles that stream through the galaxy. Inside dense clouds they matter a great deal: they heat the gas, which can slow its collapse into new stars, and they ionise molecules, driving the chemistry from which more complex molecules form. Until now, however, astronomers could only estimate how many cosmic rays penetrate such clouds indirectly, by modelling chemical reactions, and the estimates varied widely.

Bialy's group had predicted that when cosmic rays strike molecular hydrogen, the most common molecule in these clouds, they leave it in an excited state that releases a faint, characteristic infrared glow. The team pointed the James Webb Space Telescope at Barnard 68, a compact dark nebula about 400 light-years from Earth, and detected emission at the expected wavelengths, around 100 terahertz in frequency. The signal matched their model, while alternative explanations did not fit the data. A companion analysis with Johns Hopkins was published in the Astrophysical Journal.

According to the Technion, NASA has approved 50 more hours of Webb observing time so the team can apply the method to other clouds, with the aim of mapping cosmic rays across the galaxy. Neufeld said the telescope had opened a new window on cosmic-ray astrophysics.