Sept. 15—NASA announced Sept. 10 that the Perseverance rover had come across some rocks with green, blue, black and white minerals which, on Earth, would traditionally indicate microbial activity. The colorful speckles come from two minerals. The blue-green mineral is called vivanite, which is well known by scientists to form during the decay of organic material. There is also a dull brown mineral called greigite, and when these two minerals are found together, it is usually an indication of microbial metabolism. These specks are large enough to be seen by the naked eye, which is rare for ancient microscopic life.

Joel Hurowitz, the lead author of a study published in Nature, said that the rocks were “probably the most astrobiologically exciting” samples identified by Perseverance. Hurowitz continued, “The sample contains what we believe to be a potential biosignature. Microbes will eat the organic matter and react with the mud, and the by-product of that reaction is these minerals. That’s kind of why we’re as excited as we are about this.”

Some scientists say that there is a chance that the minerals could have formed due to great heat and without microbes. However, several studies of these samples determined that the rocks were not subject to extreme heat. Hurowitz said that all of the evidence “seems to point more strongly towards the possibility of microbial activity.” Scientists say that the only way to definitively confirm any ancient microbial activity would be to examine the samples in person in order to make detailed mineralogical and chemical analyses. Recent cuts in the NASA budget indicate that that won’t happen anytime soon. While the search for life in other planets would simply seem to be an “interesting find” for most people, it would more fundamentally tend to bolster the hypothesis of Vladimir Vernadsky and Louis Pasteur that life is something unique and autonomous, and not at all a byproduct of some inorganic chemical combination, as is generally believed in scientific circles today.

Perseverance has been scouting Mars since 2021 and is currently in the Jezero Crater, which was a lake billions of years ago. The rocks were found in what was muddy sediment that accumulated at the bottom of an ancient river valley called Neretva Vallis.