Materials found in rocks in Mars' Jezero Crater suggest that organic matter may be widespread on the red planet.

Spectroscopic analyses using instruments on the Perseverance rover have revealed evidence of hydrocarbon molecules in numerous rock formations. Moreover, the detections show different abundances and types of molecules in different rocks.

It is not the first time organic molecules have been detected in our planetary neighbour - the Curiosity rover also found them in Gale Crater - but the discovery suggests that the building blocks for life may be widespread on Mars and provided by different formation mechanisms.

"We detected signals consistent with aromatic organic molecules in a large number of rocks on the Jezero crater floor," Sunanda Sharma, an astrobiologist at Caltech who led the research, told ScienceAlert.

"We see at least four different types of fluorescence signals and three types of Raman signals, which are probably organic. It appears that the number of fluorescence detections and the diversity of fluorescence signals is higher in the Máaz unit compared to the Séítah unit. This was surprising and interesting, because such differences could mean that the units have different alteration histories."

One of Perseverance's primary goals is to look for signs of habitability on Mars. Carbon chemistry is not evidence for this, of course; there are many non-biological processes that can produce carbon-based molecules. But carbon is essential for life as we know it, so if you want to assess habitability, carbon-containing molecules are one of the most important things to look for.

The ability of rocks to preserve these molecules is also important. These features in an area suggest that at some point in Mars' history, life may have arisen or been supported there.

Using Perseverance's SHERLOC instrument, Sharma and colleagues applied Raman and fluorescence spectroscopy to rocks from the Máaz and Séítah formations, looking for signatures of carbon chemistry. Not only did they find the signals they were looking for, they also found significant differences in chemistry between the rocks.

"I was most interested in the comparisons between units," says Sharma.

"Máaz and Séítah did not look the same in terms of the number, type and mineral relationships of possible organic signals. Now I wonder what they might have gone through to come up with these differences; how does this fit into our Jezero crater story?"

Although the exact molecules have not yet been identified, both formations show signs of aqueous alteration. This means that water may have played a role in the formation of the compounds, another important ingredient for habitable conditions in the past.

The rover has since moved on and more data is on its way. The next step is to compare different rock formations at new locations. This could help researchers piece together a more detailed geological history of Mars and the organic molecules on it.

The team hopes that the widespread presence of organic matter means that it will also be found in the samples Perseverance is preparing to return to Earth. If this is the case, one day we will have the opportunity to study them directly.

Sharma says: "This is an important piece of the puzzle we are building about the presence, distribution and types of organic matter on Mars."

 

Source: https://www.sciencealert.com/