A survey of red dwarf stars suggests that, in our galaxy alone, there are tens of billions of planets orbiting their stars' 'habitable zones.'
There should be billions of habitable, rocky planets around the faint red stars of our Milky Way galaxy, a new study suggests.
Though these alien planets are difficult to detect, and only a few have been discovered so far, they should be ubiquitous, scientists say. And some of them could be good candidates to host extraterrestrial life.
The findings are based on a survey of 102 stars in a class called red dwarfs, which are fainter, cooler, less massive and longer-lived than the sun, and are thought to make up about 80 percent of the stars in our galaxy.
Using the HARPS spectrograph on the 3.6-metre telescope at the European Southern Observatory's La Silla Observatory in Chile, astronomers found nine planets slightly larger than Earth over a six-year period. These planets, called super-Earths, weigh between one and 10 times the mass of our own world, and two of the nine were discovered in the habitable zone of their parent star, where temperatures are right for liquid water to exist.