Nasa Perseverance rover finds intriguing rocks in search for alien life

In its first year on Mars, Nasa’s Perseverance rover has discovered, sampled, and stored Martian rocks showing signs of interaction with ancient water on the Red Planet, samples that may prove the best chance of determining whether there is, or ever was, life on Mars.

Scientists now present in detail their findings stemming from the Perseverance mission in four papers published Thursday, two in the journal Science, and two in Science Advances. The collected findings discuss the rover’s exploration of Jezero crater on Mars, the site of an ancient lake and river bed, the geological structure of the region, and the rock samples the rover collected that will be returned to Earth by a separate mission.

Perseverance landed on Mars in February 2021, and as detailed in the first paper published in Science, the rover found the former lakebed of Jezero crater to be more eroded than scientists first anticipate, allowing the rover to sample deeper strata of Mars rocks than anticipated. Those rocks showed significant signs of being chemically altered by contact with water.

“We have organisms on Earth that live in very similar kinds of rocks,” University of Florida astrobiologist and one of the study authors Amy Williams said in a statement. “And the aqueous alteration of the minerals has the potential to record biosignatures.”

The Perseverance findings build on those of Nasa’s earlier Mars rover missions, such as Curiosity, which celebrated its 10th anniversary of landing on Mars on 5 August. The still active Curiosity helped establish the fact of a watery ancient past on Mars, and also confirmed the presence of organic molecules, the building blocks of life, on the Red Planet.

Perseverance is very much an intentional successor to Curiosity, designed to expand scientists’ understanding of the ancient watery phase of Mars.

The second paper published in Science looked at the nature of the rocks at the bottom of Jezero crater, and found evidence of igneous rocks — rocks formed by cooling magma — which will be especially helpful in determining a detailed timeline of the era of water on Mars.

“From a sampling perspective, this is huge,” University of California, Berkeley geochemist and study author David Shuster said in a statement. “The fact that we have evidence of aqueous alteration of igneous rocks — those are the ingredients that people are very excited about, with regard to understanding environmental conditions that could potentially have supported life at some point after these rocks were formed.”

The two papers in Science Advances examined ground radar data from Perseverance characterizing the subsurface structure beneath the vehicle to a depth of 15 meters, and the mineral content of the subsurface layers.

The current findings are in a sense preliminary, as the most in-depth results from the Perseverance mission will come in 2033. That’s when Nasa’s Mars Sample Return mission brings the rocks now archived by the rover back to Earth where full scale laboratories can analyze the samples, and perhaps answer the question of whether there has ever been life on Mars once and for all.