Mars probe detects particles that may have been left behind by Martians (but other, less exciting explanations are conceivable)

Perseverance has found promising organic molecules in Jezero crater, which are also seen as “the building blocks of life.” But whether or not Martian microbes actually left them remains in question.

It’s been nearly two years since the Mars Perseverance rover touched down in Jezero Crater on Mars. Since then, the Mars rover has been carefully scanning the crater, looking for signs of (former) life. And the thief may have just found it. For example, perseverance appears to have detected evidence of different types of organic molecules, the researchers say.

organic molecules
Existing organic molecules are a class of carbon-based molecules. “They correspond to carbon-containing molecules that are the building blocks of life as we know it,” says team member Ashley Murphy. “This is one of the first times we’ve found potential organic material in Jezero Crater.” So the discovery is very exciting. Because the discovered organic molecules may have been left behind by ancient microbial life! Although this does not have to be the case.

The basic building blocks of life
Organic molecules are composed primarily of carbon and usually contain hydrogen and oxygen atoms. It may also contain other elements such as nitrogen, phosphorus, and sulfur. The discovery of such organic molecules is important because some of these compounds are the building blocks of life. The presence of these specific molecules is considered a potential biosignature – a substance or structure that could be evidence of past life. Scientists remain cautious. Some organic molecules can also be created through chemical processes, without the existence of life.

There is no biological origin
“Not all organic molecules have a biological origin,” Murphy explains. This is why it is important to study the relationship between minerals and organic matter. Everything we know about life on Earth is limited to what is preserved in rocks and minerals. On Earth, biosignatures are found in certain minerals, and some minerals are better at preserving organic matter than others.”

Mars and Earth
This means that researchers often use Earth as an example to see what might happen on Mars. “Mars may have had a similar early geological history to Earth, so we are using our knowledge of life as we know it on Earth to look for possible evidence of earlier life on Mars,” Murphy said. “Mapping organics provides a better understanding of the carbon cycle on Mars. We can then determine whether it is similar to or different from Earth. It will also tell us more about how likely Mars is to have harbored life.”

Sherlock
Organic molecules were detected using Perseverance’s SHERLOC instrument. SHERLOC – short for Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals Ultraviolet laser is used to identify minerals in rocks. In addition, the device is equipped with cameras and spectrometers to search for organic materials and minerals that may be signs of microbial life in the past. “The Sherlock tool installed on the Perseverance robotic arm allows us to assess potential biosignatures,” Murphy explains.

Moaz is in an argument
Researchers used the SHERLOC instrument to take a closer look at two Martian rock formations, Moad and Intermediate. Perseverance drilled small holes in the rock for this purpose. The team found traces of organic molecules in all 10 places. “Potential organics are found in multiple layers,” says Murphy. “This may indicate that Mars once had distinct surface processes and relatively complex organic chemistry. On Earth, this is associated with some habitable environments where signs of ancient life could be preserved.”

Other discoveries
By the way, this is not the first time that organic matter has been found on Mars. Both Perseverance and Curiosity have encountered this before. “The newly discovered particles are similar to those previously found in Gale Crater and in many meteorites,” Murphy said. “The discovery of diverse organic material in two ancient lakes (Gail and Jezero craters) is important for our understanding of the scale and diversity of surface processes and how this relates to the habitability of the planet.”

Origin
But again, the discovery is by no means confirmation of life on Mars. Organic molecules can be formed in a number of ways, including through non-biological processes such as water-rock interactions, deposition by interplanetary dust or meteorites, or by synthesis with volcanic materials. At the moment, it is not yet clear the exact origin of the organic molecules that have surfaced.

Although the organic materials are not evidence of past life, the discovery is still exciting because it shows that Mars has the building blocks for life. The samples will now have to be returned to Earth and examined in more detail before any definitive conclusions can be drawn. So we will have to be patient for a while before it is decided once and for all whether there is (or was) life on Mars.