Researcher believes microbial life fossils exist on Mars

Are we close to discovering that there really is (or was) life on Mars? The statements by one researcher raised the issue that never really comes out of the debates of astronomers and those interested in life in space.

Nora Noffke, a geobiologist at Old Dominion University in Virginia, is the leader of a very thorough study of images taken by NASA's Curiosity spacecraft. This thorough research revealed intriguing similarities between ancient sedimentary rocks on Mars and microbial structures on Earth.

The results were published in the scientific journal Astrobiology and suggest that life may have previously existed on the Red Planet. The images were captured in the geological formation called Yellowknife Bay, in a location that would have been a lake bed (now dry Lake Gillespie) that suffered seasonal flooding billions of years ago.

According to scientists, at that remote time, Mars was a much warmer and wetter planet than today. On Earth, colonies that are like “rugs” of microorganisms rearrange sediments in shallow bodies of water, such as lakes and coastal areas, forming distinct characteristics that fossilize over time.

These fossils, known as microbially-induced sedimentary structures (MISS), are found in the above-mentioned environments around the world and in ancient rocks, which may reveal much about Earth's history.

Studies

Nora Noffke is a geobiologist specializing in such fossil structures. So much that she spent the last 20 years studying them and was the lead author of the research that revealed the discovery of the oldest traces of life on our planet. According to this 2013 study, these signs of life were found at Dresser Formation in Australia and are 3.48 million years old.

In Astrobiology's Johnny Bontemps article, Noffke details the striking morphological similarities between Martian sedimentary structures on Lake Gillespie (which is at most 3.7 million years old) and Earth's microbial structures.

However, it should be noted that although the researcher has at hand possible evidence of signs of ancient life on Mars, her report is not definitive proof that these structures were formed by living organisms. They could, for example, have been created by abiotic processes.

The big problem is that obtaining this confirmation would require returning Curiosity to the same location to take rock samples for further microscopic analysis and comparing them with those of Earth. And this mission is not expected to happen anytime soon, because the images studied were taken by the spacecraft in 2012 and, currently, the vehicle is already far away from that location.

Although not yet confirmed, other experts approve the findings. "The fact that she pointed out about these structures is a major contribution to the field. Along with recent reports of methane on Mars, her findings add an intriguing piece to the enigma of a possible story for life on the neighboring planet." said Penelope Boston, a geomicrobiologist at the New Mexico Institute of Mining and Technology.

Image analysis

In the Astrobiology article, researcher Nora Noffke reported how she made the analyzes and discoveries in the images:

"In an image, I saw something that looked very familiar. So, I took a closer look and spent several weeks investigating certain images, inch by inch, drawing sketches, and comparing them with data from ground structures. And I I have been working on this for 20 years, so I knew what to look for, "she said.

Noffke compared the spacecraft images with those taken at various locations on Earth, including modern sediment surfaces on Mellum Island, Germany; Portsmouth Island in the United States and Carbla Point in Western Australia. She also compared them to the oldest microbial carpet fossils in Bahar Alouane, Tunisia; the Pongola Supergroup in Africa and the Dresser Formation in Western Australia.

As a result, she found that the photos showed striking morphological resemblance between terrestrial and Martian sedimentary structures. The distribution patterns of microbial structures on Earth vary depending on where they are found.

Different types of structures are found together in different types of environments. For example, microbial mats that grow in rivers create a different set of associations than those that grow in seasonally flooded environments. And the patterns found in Gillespie's Martian Lake are consistent with the microbial structures found in similar environments on Earth.

Still, many more studies will be needed to confirm this new evidence, and researcher Nora Noffke knows this. "Right now all I would like to do is point out these similarities, but other evidence must be provided to verify this hypothesis, " she said.