How do I … prove there’s life on Mars?

Awful as it is to have to admit, we're more likely to find microbes than a Martian iguana or a mist of sentient atoms - and that's only if we manage to analyse the evidence without contaminating it

This week Nasa announced it had found evidence of liquid water on the surface of Mars. The space agency said the "dark streaks" on the walls of the Garni crater were proof of flowing water on the planet, evidence that a habitable environment was "at least possible"; and they might show them the most likely sites for finding life on Mars.

This was huge news, prompting headlines around the world and excitable, scientifically undereducated types like myself to believe the first interplanetary BBQ with our new friends was just decades away.