Scientists have recreated Martian conditions in test tubes, producing a “disinfectant” that may help explain the planet’s rusty red color and why life and organic material have not been found on the surface. The chemical is superoxide; a “free radical” or oxidant like those implicated in human cell damage from cigarette smoking, radiation and diseases like heart disease and cancer. “You would not expect life to exist at the immediate surface of Mars because production of these oxygen radicals will destroy organic molecules,” said planetary geochemist Albert Yen of NASA