NASA's Perseverance rover is finding organic elements all over Mars, sometimes in harsh conditions. This may indicate that life once existed on Mars.
Perseverance has recently found an abundance of organic molecules, which may have been left by living things or abiotic chemical processes, in a river delta inside the Jezero crater on the Red Planet. Several billion years ago, there was a large lake at this location. According to NASA, all objects that have been scanned so far for organic molecules contained traces of them.
Although previous missions have detected organic elements on the red planet, Perseverance is using the new Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instrument to see unprecedented detail about these molecules.
SHERLOC has analysed aromatic substances, ring-shaped organic molecules, in a core collected by Perseverance from a rock called Wildcat Ridge, which contains a rich sedimentary record of minerals, including salts called sulphates, that were buried in a lake when water existed on Mars more than three billion years ago.
Sunanda Sharma, a SHERLOC scientist at NASA’s Jet Propulsion Laboratory, said:
On Earth sulfate deposits are known to preserve organics and can harbor signs of life which are called biosignatures. This makes these samples, and this set of observations, the most intriguing that we've done so far in the mission.
Perseverance is tasked with drilling for samples from different areas as it passes through the Jezero crater, a formation that includes a system of river deltas with conditions that could be favourable to life.
In the future, samples collected by the rover will be transmitted to Earth by NASA's next mission.
So far, Perseverance has collected 12 samples and studied countless formations on Mars, giving scientists a glimpse of the red planet's early environment, when it was wetter and warmer.
Perseverance has confirmed that signs of life exist on Mars and has shown that these organic molecules are stable. The rover's discovery of organics in sulphate deposits also hints that fossilized microbes, if they do exist, could be perfectly preserved in the cores Perseverance is selecting for a future trip to Earth.
This is a treasure hunt for potential signs of life on another planet. Organic matter is a clue, and we're getting stronger and stronger clues.