Was there ever life on Mars?<\/em> After 21 Mars landers, and a host of spacecraft observing from orbit, we still don\u2019t know. The search of past Martian life has focused primarily on biosignatures \u2013 chemical evidence in rocks, or in the air \u2013 left behind by once-living microorganisms. Those sorts of clues need to be puzzled out in laboratory analysis. But what if we could see<\/em> telltale signs of biology in Mars\u2019 rocky landscape? The Mars rovers have sometimes seen tantalizing and unusual shapes or other features. Mostly, these have been explained as erosion due to Mars\u2019 thin atmosphere. But on September 27, 2023, the Perseverance rover came across another oddity: circular formations that resemble those made on Earth by microbes in some lakes. <\/p>\n The jury is still out, but let\u2019s take a look.<\/p>\n Space journalist Leonard David, in his blog Leonard David\u2019s INSIDE OUTER SPACE<\/em>, wrote about the finding on November 5, 2023. NASA released the images recently as part of the daily upload of new images from the rover. There\u2019s no published analysis or paper yet, so right now we just have the images and comments from scientists on the mission team.<\/p>\n The 2024 lunar calendars are here! Best Christmas gifts in the universe! Check \u2019em out here.<\/p>\n The rover has been exploring the remains of an ancient delta in Jezero crater. This is where a river once flowed into the lake that existed inside the crater billions of years ago. The delta is still clearly visible from above. NASA sent Perseverance to Jezero crater specifically for this reason, as it would be an ideal location to search for evidence of past microbial life.<\/p>\n As noted above, that search is mostly about looking for traces of biosignatures that originated from microbes. To be sure, the rover has already discovered abundant organic molecules in the samples it has tested in its onboard laboratory. However, this isn\u2019t proof of past life yet. That will likely require \u2013 if<\/em> any life did actually exist \u2013 getting some of those samples back to Earth to study in more advanced labs.<\/p>\n Several weeks ago, Perseverance came across something intriguing: circular formations of rock with concentric curves. They seemed to resemble similar formations on Earth called stromatolites and microbialites. They are created by microbial communities in some lakes, in a process combining biology and geology. Could it be? Perseverance did land in an ancient lake bed \u2026 The Great Salt Lake in Utah has some great examples of stromatolites. On Earth, they are created by a combination of bacteria and calcium carbonate. They also resemble reefs, but are not actually made of coral. Could a similar process have happened on Mars?<\/p>\n Steven Ruff, a Mars geologist at Arizona State University, weighed in on the discovery on his YouTube channel Mars Guy. As quoted in the blog post by Leonard David, Ruff said:<\/p>\n In the very place it might be reasonable to expect, Perseverance discovered circular rock structures resembling ones formed by microbial communities in some lakes on Earth. This exciting possibility called for a closer look.<\/p>\n<\/blockquote>\n![\"Rock](\"https:\/\/earthsky.org\/upl\/2023\/11\/Perseverance-rover-Mars-circular-rock-formation-sol-925-September-27-2023.png\")
Rock features on Mars raise questions<\/h3>\n
Unusual rock features on Mars<\/h3>\n
Mars Guy<\/h3>\n
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