A small comet has been spotted slowing down and then speeding up again – but in the opposite direction, which we have never seen before
Some gut bacteria recycle discarded sex hormones, like oestrogens, back into the body. The level of these bacteria seems to be higher in industrialised societies, which could have big implications for our health
A fresh and important book reveals the messy reality of our ever-mutating cells – and why the quest to defeat ageing is futile, says Michael Le Page