Little green men on alien planets may be discovered even once they have died out, especially if their demise was sudden. So suggests a model of our world after the sun becomes a red giant. Earth's grim future emerged last year when Jack O'Malley-James of the University of St Andrews, UK, and colleagues modelled the sun's expansion into a red giant. As Earth heats up in 1 billion years'time animals and plants die, leaving microbes as the only survivors. As complex life is likely to exist for relatively short periods on alien planets too, this seemed to lower the odds of us finding them before they die out.
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