FAST finds two mysterious hydrogen clouds with no visible stars

Astronomers have found two clouds of hydrogen near the Whirlpool galaxy that appear to contain almost no stars. The clouds, discovered with China's FAST radio telescope, each contain roughly 3 million times the mass of the sun in hydrogen but have no detectable optical counterpart. Their properties are outlined in a new paper published in the Astronomy & Astrophysics journal on Aug. 4.