We call them “Martians” because, in science fiction, Mars has always been the natural home of extraterrestrials. In fact, of all the planets in the solar system, Mars is the prime candidate to host life, after Earth, of course. Indeed, Mars is on the outer edge of the habitable zone, that area around the Sun that delimits the space where the temperature is low enough to ensure that the water remains in a liquid state. And where there’s water, it is well known, there’s probably life. Yet it’s cold on Mars today, and so far, all the probes and rovers we have sent to the surface of the red planet have found no signs of life.
