NASA engineer says Viking missions discovered life on Mars in the 1970s

Gilbert Levin, a NASA engineer who worked on the Viking missions, says he’s “convinced we found evidence of life of Mars in the 1970s.” In a Scientific American article published today, Levin explains how two separate craft landed on the surface of the red planet and conducted a series of tests to determine if there were was life. One particular test, based on the same experiment Louis Pasteur conducted to prove the existence of microbes, came back positive. The results were c