The total number of stars in the Universe "is likely three times bigger than realized." Yale University astronomer Pieter van Dokkum says there are "possibly trillions of Earths orbiting these stars," dramatically increasing the possibility of finding alien civilizations.
According to the new study just published in Nature, new observations on the red end of the optical spectrum at the W. M. Keck Observatory in Hawaii show an overwhelming population of red dwarfs in eight massive nearby elliptical galaxies. The team has discovered that these galaxies hold twenty times more red dwarfs than the Milky Way.
Van Dokkum says that "there are possibly trillions of Earths orbiting these stars" which are "typically more than 10 billion years old." According to him, that's long enough for complex life to evolve, which is "one reason why people are interested in this type of star." In fact, astronomers discovered the first exoplanet similar to our own Earth—and therefore capable of harboring complex life—orbiting the Gliese 581 red dwarf star system, 20.3 light years from our home planet.
Carl Sagan explains why this discovery has a dramatic impact in our search for intelligent life in the Universe, using the Drake Equation:
Logically, if you increase the number of stars in the universe by three, the number of potential extraterrestrial civilizations increases by three times as well. Whether we make contact or not is another story.
The discovery doesn't only have a deep impact on the search for extraterrestrial life, but also on our understanding of galaxy formation and the Universe itself. Team member Charlie Conroy—of the Harvard-Smithsonian Center for Astrophysics—says that this might be a sign that galaxies contain less dark matter than originally suspected, since the abundance of red dwarfs "could contribute more mass than realized" to the Universe. [Nature and Keck Observatory]