Has there ever been life on Mars? Scientists have pondered this question for years, and a recent discovery suggests it just might be possible!
NASA’s Perseverance rover, which has been exploring Mars since 2021, fired its laser at some oddly pale rocks on the surface of the Red Planet—and found evidence that Mars may have once been warm, wet and possibly even suitable for life.
“We have known for a long time that Mars had lakes and rivers, but many people suspect that temperatures were still quite cold, given Mars’ distance from the sun,” geologist professor Roger Wiens of Indiana’s Purdue University told Newsweek.
In their study, Wiens and colleagues detail how they used Perseverance’s laser-equipped SuperCam to analyze small white pebbles and larger rocks scattered across the Martian surface.
These rocks turned out to contain a mineral called kaolinite, which on Earth forms in warm, rainy environments or near hot springs—places that are ideal for life.
Wiens estimates that the rocks—found in an ancient riverbed and strewn uphill on the rim of Jezero Crater—are several billion years old.
He told Newsweek: “The surprising aspect of these rocks is that kaolinite requires relatively warm temperatures, a wet environment, and long time periods to form. It ups the ante in terms of the ancient climate of Mars, suggesting that it had to be quite warm, at least for some extended time periods.”
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What Is Kaolinite?
Dr. Sean McMahon—an astrobiologist at the University of Edinburgh, who was not involved in the present study—told Newsweek that kaolinite is familiar to us on Earth as the soft “china clay” that we use to make ceramics.
Kaolinite forms when older rocks are broken down by liquid water. The mineral, which is rich in aluminum, is left behind after the water has leached away iron and magnesium.
He said: “Although minerals like kaolinite have been detected from orbit at many locations across Mars, it is exciting to see them up close like this and to literally ‘ground-truth’ those detections.
“Whether this kaolinite was produced by rain and snowmelt or by underground hydrothermal activity, it probably represents an environment that was warm and wet enough to support life billions of years ago.
“Kaolinite-rich sediment is also very good at preserving organic molecules and preventing them from decaying, so this is an encouraging detection.”
Wiens added: “Our confirmation of kaolinite rocks on Mars is further evidence that our sister planet had a very suitable climate in which microbial life could have existed. It justifies our search for ancient life on the Red Planet.”
The Search for Clues Continues
Perseverance first noticed these pale rocks when it landed, but the team was too focused on other tasks to investigate them right away. Later, when the rover came across larger pieces of the same kind of rock lying on the surface—geologists call these “float rocks” because they are not attached to the bedrock—they decided to take a closer look.
Since then, researchers have found more than 4,000 of these rocks scattered across the terrain. While they don’t yet know exactly where they came from, satellite images show similar kaolinite-rich rocks in the rim of Jezero Crater, where Perseverance is currently exploring. Scientists are now eager to find the original source of these rocks to better understand Mars’ past environment.
Water is a key ingredient for life. The more we learn about water on Mars—how much there was, how long it lasted, and where it went—the better we can understand whether life ever existed there.
If Mars once had conditions similar to Earth’s, then it is possible microbial life could have thrived there billions of years ago.
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Reference
Royer, C., Bedford, C. C., Johnson, J. R., Horgan, B. H. N., Broz, A., Forni, O., Connell, S., Wiens, R. C., Mandon, L., Kathir, B. S., Hausrath, E. M., Udry, A., Madariaga, J. M., Dehouck, E., Anderson, R. B., Beck, P., Beyssac, O., Clavé, É., Clegg, S. M., … Maurice, S. (2024). Intense alteration on early Mars revealed by high-aluminum rocks at Jezero crater. Communications Earth & Environment, 5(1). https://doi.org/10.1038/s43247-024-01837-2