SETI Expands Hunt for Extraterrestrial Life to 20,000 More Star Systems
SETI just expanded its search for intelligent aliens in a big way. Over the next two years, a new initiative will search 20,000 star systems that have been neglected by astronomers in the past: the exoplanets surrounding red dwarf stars.
Red dwarf stars are generally not as bright as stars like our Sun, which made astronomers believe that habitable planets were highly unlikely to exist in these star systems. If the star is dimmer, then the habitable zone is necessarily both narrower and closer to the star. As a result of the close proximity, any planet in the habitable zone may become tidally locked, or would stop rotating and have one side permanently facing the star, which would make the temperatures on both hemispheres too extreme for the evolution and persistence of life.
But according to new research, red dwarfs may be perfectly adequate Sun substitutes. Recent studies have shown that between one-sixth and one-half of red dwarfs have planets in their habitable zones, which is comparable to Sun-like stars. Furthermore, we now know that if the tidally locked planets had oceans and an atmosphere, then a significant amount of heat would be transferred from the light side to the dark side, which means part of the planet would be habitable.
SETI astronomer Seth Shostak also explained that it is easier to observe red dwarfs, because there are more red dwarfs that are close to our solar system:
There's even a chance that red dwarfs could be better candidates for hosting habitable planets than Sun-like stars. Red dwarfs burn much longer than Sun-like stars; on average they burn longer than the current age of the universe, and every single red dwarf that ever existed is still burning today.