The world is not prepared for the discovery of life on another planet even though it may only be a couple of years away, Nasa’s Chief Scientist has warned.

Next summer, two rovers from Nasa and the European Space Agency (ESA), will travel to Mars to drill horizontally into rocks and deep into the surface, in the hope of finding evidence of living organisms.

The missions are the best chance humanity has ever had of answering the question: ‘Are we alone in the universe?’

Dr Jim Green, who has been instrumental in both missions, told The Telegraph that there is a real possibility that one or both will be successful. Yet it would have far-reaching implications, and he believes Earth is not ready.

“It will be revolutionary,” he said. “It’s like when Copernicus stated ‘no we go around the Sun’. Completely revolutionary. It will start a whole new line of thinking. I don’t think we’re prepared for the results. We’re not.

“I’ve been worried about that because I think we’re close to finding it, and making some announcements.

“What happens next is a whole new set of scientific questions. Is that life like us? How are we related? Can life can move from planet-to-planet or do we have a spark and just the right environment and that spark generates life - like us or not like us - based on the chemical environment that it is in?”