Clouds are pretty to see. They are also much more potent than previously perceived in modifying climate. This is particularly important when considering habitable planets near red dwarf stars. A new study that calculates the influence of cloud behavior on climate doubles the number of potentially habitable planets orbiting red dwarfs, the most common type of stars in the universe. This finding means that in the Milky Way galaxy alone, 60 billion planets may be orbiting red dwarf stars in the habitable zone. Researchers at the University of Chicago and Northwestern University based their study, which appears in Astrophysical Journal Letters, on rigorous computer simulations of cloud behavior on alien planets. This cloud behavior dramatically expanded the estimated habitable zone of red dwarfs, which are much smaller and fainter than stars like the sun.