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As we meticulously scrutinize high-resolution images that are sent to Earth by NASA’s Curiosity rover on Mars, we see strange formations, configurations that seem artificial, and rocks of all kinds that have caused people from all around the world to believe intelligent beings (or, at least, some sort of life form) inhabited the red planet in the distant past.
Sometimes the Martian landscape plays tricks with our imagination, and sometimes suspiciously observed characteristics match natural processes that we have seen on our own planet. But now, in an article published in the journal Astrobiology, one geobiologist found in images of sedimentary rock from Mars, proof of structures created by microbial life on the red planet.
The discovery was made by Nora Noffke, a geobiologist at Old Dominion University in Virginia. She has spent the past 20 years studying these microbial structures. In 2014, she reported the discovery of MISS that are 3.48 billion years old in the Western Australia’s Dresser Formation, making them potentially the oldest signs of life on Earth, a discovery of huge importance if we are to understand how life evolved on Earth.
Now, Noffke details striking morphological similarities between Martian sedimentary structures in the Gillespie Lake outcrop (believed to be at most 3.7 billion years old) and microbial structures on Earth.
The image in question was taken by the Curiosity rover on Lake Gillespie, an area located in the Bay of Yellowknife, Gale Crater where the rover arrived in December 2012. The sedimentary rock photographed by Curiosity is sandstone, which formed when Mars had water on its surface. The layers of sedimentary rock and conglomerations that exist in them led scientists to conclude that Curiosity was exploring an ancient lakebed.
The Martian Lake Gillespie, which has been dated to around 3,700 million years, seems to have its very own structures which can be attributed to ancient Martian microbes. In her study, Noffke emphasizes that his is only a hypothesis and should be taken as such while she is certain that this meets the necessary goal of explaining the process of formation responsible for the visible structures on the surface of sedimentary rocks on Mars.
“All I can say is, here’s my hypothesis and here’s all the evidence that I have,” Noffke says, “although I do think that this evidence is a lot.”
“The fact that she pointed out these structures is a great contribution to the field,” says Penelope Boston, a geomicrobiologist at the New Mexico Institute of Mining and Technology. “Along with the recent reports of methane and organics on Mars, her findings add an intriguing piece to the puzzle of a possible history for life on our neighboring planet.”
To check out all of the images used by Noffke in her study, click here.
So… traces of life on Mars?
Mars is just incredibly interesting since it is so different yet so similar to Earth and in the views of many people around the globe if there was life anywhere else in the solar system than that place is surely Mars.
“I’ve seen many papers that say ‘Look, here’s a pile of dirt on Mars, and here’s a pile of dirt on Earth,” says Chris McKay, a planetary scientist at NASA’s Ames Research Center and an associate editor of the journal Astrobiology. “And because they look the same, the same mechanism must have made each pile on the two planets.’”
McKay adds: “That’s an easy argument to make, and it’s typically not very convincing. However, Noffke’s paper is the most carefully done analysis of the sort that I’ve seen, which is why it’s the first of its kind published in Astrobiology.”
Mars has proven to be far more similar to Earth in many ways than what scientist have been willing to accept. After over 3 years of collecting data, images and readings from Mars, researchers are finally accepting the idea that Mars could have been inhabited by life forms in the distant past when the red planet had an atmosphere similar to that of Earth, rivers, lakes and oceans.
“In one image, I saw something that looked very familiar,” Noffke recalls. “So I took a closer look, meaning I spent several weeks investigating certain images centimeter by centimeter, drawing sketches, and comparing them to data from terrestrial structures. And I’ve worked on these for 20 years, so I knew what to look for.”
Noffke meticulously compared several images taken on Mars by NASA’s rovers to several sites photographed on Earth including modern sediment surfaces in Mellum Island, Germany; Portsmouth Island, USA; and Carbla Point, Western Australia; as well as older fossils of microbial mats in Bahar Alouane, Tunisia; the Pongola Supergroup in Africa; and the Dresser Formation in Western Australia. Interestingly, the images showed incredible morphological similarities between the terrestrial and Martian sedimentary structures.
Researchers note that distribution patterns of microbial structures on our planet usually vary depending on where they are found. This is why different types of structures are located together in different environments. As noted by astrobio.net, microbial mats that grow in rivers will create a different set of associations than those that grow in seasonally flooded environments.
Interestingly, the patterns which Noffke found in the Gillespie Lake outcrop are consistent with the microbial structures found in similar environments on Earth.
But the similarities found by Noffke are quite a few. According to the geobiologist, terrestrial structures change in a certain way over time, and this is something Noffke found on Mars since the distribution pattern in Martian rocks eerily resembles microbial structures on Earth which have changed over time. This is why Noffke has been able to make strong arguments with respected data even though she has also taken the time to describe other processes that could have created similar patterns. In her study, Noffke noted that the chips, pits, and cracks could be the product of erosion by salt, water, or the wind.
“But if the Martian structures aren’t of biological origin,” Noffke says, “then the similarities in morphology, but also in distribution patterns with regards to MISS on Earth would be an extraordinary coincidence.”
“At this point, all I’d like to do is point out these similarities,” she adds. “Further evidence must be provided to verify this hypothesis.”
Even though confirmation of the discovery made by Noffke is still pending, the geobiologist has outlined a strategy to confirm the potential biological nature of the Martian structures, the only issue is… returning a sample to Earth in order to properly test it. Since this is not an option at the moment, Noffke has listed a series of measurements NASA’s Curiosity rover could perform if it came across similar structures again, one of them is looking for organic chemical signatures using the SAM (Sample Analysis at Mars) instrument, something that according to McKay wouldn’t work: “In principle, that instrument could tell us something about the nature of these materials biologically, if there were still large amounts of biological organics in the samples,” he explains. “But these are just ancient sedimentary structures, and biology has long since left.”
“What’s more, in practice this instrument is restricted,” he adds. “There was a contamination spill in the instrument presumably during landing. So it has a very high background contamination level.”
So, as you can see we could be onto a groundbreaking discovery, one which we cannot confirm at the moment. However, the study itself is more than incredible and proves that Mars is a planet full of surprises.