Finding new signs of water on Mars was not unlike finding a needle in a haystack. Now scientific explorers and their robot helpers face a trickier task, looking for life, a needle they are not even sure is there.
If life did exist, don’t expect traces of little green primates or even little green bugs. According to Andrew Knoll, Fisher Professor of Natural History at Harvard University, “Any life that evolved was probably very simple, on the level of bacteria and less than the width of a human hair in size. You’d need a microscope to see it.”