Mars

As part of Radio 4's Mars season, planetary scientist Monica Grady explores the search for life on the Red Planet. As a small rocky planet, Mars is similar in many respects to the Earth and for that reason, many have thought it may harbour some kind of life. A hundred years ago, there was serious talk about the possibility of advanced civilisations there. Even in early 1970s, scientists mused that plant-like aliens might grow in the Martian soil. The best hope now is for something microbial. But the discovery that even simple life survives there or did some time in its history would be a profound one. We would know that life is not something special to Earth. NASA’s Curiosity rover has discovered that 3.7 billion years ago, there were conditions hospitable to life on Mars – a sustained period of time with lakes and rivers of water. The earlier rover Spirit found deposits of silica from ancient hot springs which some planetary scientists argue bear the hallmarks of being shaped by microbes - possibly. The