NASA's Perseverance Mars rover has found organic matter in rocks on Mars - a possible sign of life!. It extracted two rock cores and abraded a circular patch to investigate the rock's composition in its bid to find signs of ancient microbial life on Mars. The rover has collected four samples from an ancient river delta in the Red Planet's Jezero Crater since July 7. Organic molecules found in the rocks consist of a wide variety of compounds made primarily of carbon and usually include hydrogen and oxygen atoms. While there are chemical processes that produce these molecules that don't require life, some of these compounds are the building blocks of life. Therefore, the presence of these specific molecules is considered to be a potential biosignature indicating life on Mars!