Evidence Shows That, Yes, Mars Once Supported Life

An international team of scientists found evidence of a glauconitic-like clay on Mars which points to the Red Planet not only having had habitable conditions but also to those conditions being stable over millennia — a requirement for life to have ever flourished on Mars.

The scientists, who reveal their findings in a paper published in the journal Nature Astronomy, discovered the substance while analyzing clay minerals extracted from Mars' Gale Crater by the Curiosity rover in 2016.

Alongside the newer Perseverance rover, Curiosity forms an integral part of NASA's plans to pave the way for humans on Mars, as well as search for signs of ancient life on the planet.

During their analysis, the researchers on the new study found that a material extracted by the Curiosity rover very closely resembles glauconitic clays here on Earth.

Earth-like clay indicates stable conditions required for life on Mars

Glauconite, an iron potassium phyllosilicate mineral, requires stable conditions over millennia in order to form. The presence of a similar material on Mars, therefore, indicates that the red planet may have had stable conditions, possibly for millions of years.

As previous research suggests the Gale Crater was once filled with water, billions of years ago, the indication of such stable conditions means that Mars may have once had a much thicker atmosphere conducive to persistent surface water.

The researchers' analysis also shows that temperatures during the period in which the glauconitic-like clay formed would have averaged between -3 to 15 degrees Celsius and that the pH in the water would have been neutral. 

All of these findings indicate that life may indeed have existed on Mars billions of years ago. Though the findings do not provide substantive evidence that life did exist on Mars, they do show that the conditions would very likely have been favorable for life over an extended time period — and time is crucial for the evolution of life on or off our planet.

Next, NASA will continue to conduct research with its Perseverance rover mission. The machine will collect more samples of Mars minerals, some of which will be analyzed by the rover itself, and some of which will be stored for humans to one day research in person once they reach Mars.