Editor’s note: A version of this story appeared in CNN’s Wonder Theory science newsletter. To get it in your inbox, sign up for free here . CNN  —  When astronomers search for evidence of life beyond Earth, what signs are they seeking? Would clues be traced to microfossils trapped within ancient Martian rocks, swim in waters of an ocean world, or lead to an Earth-like twin thought of as Planet B ? Or perhaps a technosignature, a signal that could be created by intelligent life, might point