Kepler-186f is an exoplanet orbiting the red dwarf star Kepler-186, about 490 light-years from Earth. It is the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star. It was found by the Kepler Space Observatory launched by NASA in March 2009. Based on Kepler space mission data, there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like and red dwarf stars within the Milky Way. This may mean the search for extraterrestrial intelligence (SETI) may not be in vain.