Dark matter may have been born scorching hot, defying a long-standing belief that it had to form cold. New findings show it could still cool down in time to build galaxies, rewriting what scientists thought they knew about the early Universe. Credit: AI/ScienceDaily.com Scientists from the University of Minnesota Twin Cities and Université Paris-Saclay are calling into question a long-standing idea about dark matter. Their latest findings suggest that this elusive substance may have been "