Wait, is that... human bones on Mars? Not quite, conspiracy theorists: in fact it's just a rock that happens to look a little bit like a femur thigh bone. It was snapped by the Mars rover Curiosity using its MastCam. [NASA]
Despite the best efforts of NASA, it's impossible to put craft into space that are entirely clean. Now, a study shows that Curiosity was sent up to Mars with 377 strains of microbes aboard—and up to 11 per cent may have made it to the surface of the red planet.