Here's a thought experiment that keeps planetary scientists awake at night. Strip every living thing from our planet, every bacterium, every blade of grass, every creature that has ever drawn breath and ask a simple but profound question: Would Earth still be a world capable of supporting life?
The answer, it turns out, is yes. And that finding has enormous implications for how we search for life beyond our solar system. The problem is subtle but important. Life does leave fingerprints in a planet's atmosphere. Oxygen is the classic example. Almost all of Earth's atmospheric oxygen comes from photosynthesis. Without life, a world like ours would have far less of it.
A team of researchers has built the most detailed computer model yet of a lifeless Earth, tracking how our planet would have evolved over 4.5 billion years with no biology to interfere. The work is published on the arXiv preprint server.
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