Given that about 20 percent of stars are sun-like, the researchers say, that amounts to several tens of billions of potentially habitable, Earth-size planets in theMilky WayGalaxy. “When you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-si...
If we assume the existence of 10–100 billion exoplanets in the Milky Way Galaxy, with 1% of them capable of evolving ecosystems as complex as those that might have existed at some point on Europa, that computes to the possibility of at least 100 million planets that may have seen the ...