Now that we’re getting closer to analyzing the atmospheres of terrestrial-size exoplanets, it’s worth remembering how difficult the call on the existence of life is going to be. Long-time Centauri Dreams contributor Alex Tolley takes on the issue in his essay for today, pointing out along the way just how easy it is to see what we want to see in our data. While we can learn much from terrestrial biology, new approaches looking at ‘pathway complexity’ may offer useful indications of biology and a set of markers not constrained by our own unique sample of life on Earth. A lecturer in biology at the University of California, Alex brings us up to speed with extending our methods of life detection in ways that are ‘biology agnostic.’ Expect controversy ahead — will we know life when we see it, and how can we be sure?
by Alex Tolley
Manuel Werner, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=633977
Life: [noun] The condition that distinguishes animals and plants from inorganic matter, including the capacity for growth, reproduction, functional activity, and continual change preceding death. – Oxford Living Dictionary 
Life, like pornography, is notoriously hard to define, but we mostly recognize it when we see ...