Italian astrophysicists have used data from the James Webb Space Telescope to shed new light on the nature of dark matter in the universe. Their study suggests that dark matter is made of particles that are either "cold" or just mildly "warm" with a mass larger than 2 keV, and excludes dark-matter models with particle masses that are equal to or lighter than this limit. The findings of the study provide important insights into the properties of intergalactic medium, the "cosmic web," at more recent epochs
