Data from the first 208 Martian days of Perseverance have provided a wealth of information about the Jezero Crater, where the NASA rover landed in February 2021. The crater was believed to be an ancient lake, and the latest research overwhelmingly and unambiguously confirmed that. And on top of that, the analysis shows that organic molecules were an abundant feature in these waters. This is an intriguing find in the search for ancient life on Mars.

Organic molecules are not proof that life ever existed on the Red Planet, but finding them makes the chance that life on Mars was possible more likely. In a series of papers, teams working with the Perseverance suite of instruments have found igneous rocks in the floor of Jezero Crater. These formed from magma, either related to volcanism or to asteroid impacts. And those rocks have all the hallmarks of being altered by water on multiple occasions.

“It looks like Jezero Crater is indeed what we suspected based on orbital imaging. It used to be a lake about three/three and a half billion years ago. And that's really exciting for us, obviously, because liquid water on Mars 3 billion years ago, was around the same time that life evolved on Earth. So it raises a question, did that water on Mars also contain the building blocks for life?” co-lead author Dr Joseph Razzell Hollis, from the Natural History Museum in London, told IFLScience.

Hollis and co-lead author Dr Eva Scheller used data from the SHERLOC instrument to investigate the rocks in Jezero Crater. The instrument was able to detect the fluorescence of specific organic compounds in the olivine-rich rocks studied.

“These could potentially be the building blocks of life, but we won't know for certain until we can analyze these samples in more detail. And that's why the Perseverance mission is caching samples. So it's taking samples of the rocks it finds and storing them in special sample tubes,” Dr Hollis explained to IFLScience.    

The tubes will be then collected and taken back to Earth by the Mars Sample Return mission so that they can be studied in detail, which wouldn’t be possible on Mars. The work on Earth will allow for a clearer understanding of the origin of the molecules and whether or not they could be evidence of life.

The discovery of organic molecules at the bottom of Jezero Crater, and in particular within igneous rocks, is also exciting for another reason. Curiosity found similar compounds in sedimentary rocks in Gale Crater. Finding organic materials in two very different environments on Mars strongly suggests that these organic molecules were common.

“If you're looking for the best possible chance of life evolving, you need those ingredients present. If we could only ever find them in one place, then that would suggest there was only one chance for life to have evolved. Finding them everywhere on Mars suggests that the whole planet could have potentially harbored the ingredients for life. It's just a matter of whether or not we got lucky and those ingredients happen to arrange themselves in the right way to start to form something that could eventually become a living thing,” Dr Hollis told IFLScience.

Perseverance has been studying, for the last several months, a river delta that is believed to have once brought water and sediments into Jezero Crater. Researchers believe that this is an important area for discovering organic material. Given how rich in these compounds the crater has been, the current work could be even more revolutionary.

The paper led by Sheller and Hollis is published in Science. Two other papers with complementary results are published in Science Advances, here and here.

Correction: An earlier version of this article incorrectly called carbonate an organic compound