For now, life is flourishing on our oxygen-rich planet, but Earth wasn't always that way – and scientists have predicted that, in the future, the atmosphere will revert back to one that's rich in methane and low in oxygen. This probably won't happen for another billion years or so. But when the change comes, it's going to happen fairly rapidly, the study from earlier this year suggests. This shift will take the planet back to something like the state it was in before what's known as the Great Oxidation Event (GOE) around 2.4 billion years ago. What's more, the researchers...