You can’t help but wonder what unknown worlds and, perhaps, advanced civilizations might be awaiting discovery within the final record of the Kepler spacecraft’s full field of view before the depletion of fuel permanently ended its work. NASA retired the iconic spacecraft on Oct. 30, 2018, to a safe orbit. The Kepler field of view represents 1/400 of the Milky Way Galaxy and its 100 billion stars.
Sun-like stars represent just 15 per cent of all stars in the Milky Way. More than half of those, in turn, exist in binary star systems that have also been disregarded as being too different from the conditions present in the solar system. The search for Earth twins therefore covers a nearly insignificant fraction of all the outcomes in nature.