NASA: After a year's worth of scientific scrutiny, the 'Sapphire Canyon' rock sample remains the mission's best candidate for containing signs of ancient microbial life processes. A sample collected by NASA's Perseverance Mars rover from an ancient dry riverbed in Jezero Crater could preserve evidence of ancient microbial life. Taken from a rock named "Cheyava Falls" last year, the sample, called "Sapphire Canyon," contains potential biosignatures, according to a paper published Wednesday in the journal Nature. A potential biosignature is a substance or structure that might have a biological origin but requires more data or further study before a conclusion can be reached about the absence or presence of life. "This finding by Perseverance, launched under President Trump in his first term, is the closest we have ever come to discovering life on Mars. The identification of a potential biosignature on the Red Planet is a groundbreaking discovery, and one that will advance our understanding of Mars," said acting NASA Administrator Sean Duffy. "NASA's commitment to conducting Gold Standard Science will continue as we pursue our goal of putting American boots on Mars' rocky soil."Read more of this story at Slashdot.