PSETI Seminar: A shadow biosphere as a test of the cosmic imperative

Paul Davies

Abstract:
Is the transition from non-life to life a bizarre chemical fluke or an expected part of intrinsically biofriendly laws of nature – a ‘cosmic imperative’? SETI enthusiasts assume that latter – that life will pop up inevitably in earthlike conditions. Does that mean life should have emerged many time on Earth? How do we know it didn’t? Has anybody looked? I will discuss the concept of multiple terrestrial geneses and ask whether descendants from another genesis might still lurk in the biosphere today.