d. But ill ime rock crus mylook of mild surprise. “e get t of rocks. And to be very carefullyprepared. You o make sure tamination from previous samples—no dustor anyt’s quite a meticulous process.” Sine, tly gone for coffee. Besidetaining rocks of all st of rocks at the ANU.

    Back in Bennett’s office after our tour, I noticed er giving anartist’s colorfully imaginative interpretation of Eart mig  period knoo earter sive volcanoes, and asteamy, copper-colored sea beneatromatolites, a kind of bacterial rock,filled t didn’t look like a very promising place to create andnurture life. I asked ing e.

    “ell, one sc says it ually cool ter learned t biologists, aurant problem”—because mospraviolet rays from tended to break apart anyincipient bonds made by molecules. And yet rigapped tromatolites—“you at t’s a puzzle.”

    “So  knohen?”

    “Mmmm,” sfully.

    “Eit doesn’t seem very conducive to life.”

    S t  suited life. Ot be here.”

    It certainly  ed us. If you o step from a time maco tancient Arcly scamper back inside, for to breatoday. It  ter skin. Nor  as depicted in ter inVictoria Bennett’s office. te mosptle sunligo reac little you could see   anEart recognize as our own.

    Anniversaries erial organisms  t sicular inclination to move on to anotence. At some point in t billion years of life, cyanobacteria, or blue-green algae,learned to tap into a freely available resource—t exists in spectacularabundance in er. ter molecules, supped on te, a