Ancient microbial life on Mars could have destroyed the planet’s atmosphere through climate change, which ultimately led to its extinction, new research has suggested. The new theory comes from a climate modeling study that simulated hydrogen-consuming, methane-producing microbes living on Mars roughly 3.7 billion years ago. At the time, atmospheric conditions were similar to those that existed on ancient Earth during the same period. But instead of creating an environment that would help them thrive and evolve, as happened on Earth, Martian microbes may have doomed themselves just as they were getting started, according to the study published Oct. 10...