Far from being rigid and fragile, the study of the microbial world has revealed that life at the smallest scales is deeply tenacious, and able to persist in some of the most extreme conditions on Earth. The incredible survival skills of certain forms of bacteria and archaea, including the ability to stay dormant for millions of years and survive in space, has lead some scientists to believe that life originating from a single celestial source could potentially spread to other planets and moons. Narrated by the UK physicist and TV presenter Brian Cox, this brief animation explores the arguments for ‘panspermia theory’, or the notion that microbes might be able to ‘hitchhike’ on meteoroids to spread life throughout the cosmos. Once an idea on the scientific fringes, today panspermia is being researched by an elite team of scientists at Harvard and MIT, who believe it may have been possible for microbes on Earth to spread to Mars – or vice versa.