A study published in the journal Astrobiology states that some prominent sedimentary rocks shown in Mars Curiosity photos have a remarkable similarity to structures created by life on Earth.
According to geobiologist Nora Noffke, the images of the Mars Curiosity Rover at the Gillespie Lake outcrop, situated in the Gale Crater, are similar to structures and shapes left by carpets of microbes that colonize drying lakebeds. Similar signs were used last year to date the oldest known life on Earth — in 3.48 billion-year-old rocks on the West Australian Dresser Formation.
Noffke studied an image that was taken by the Mars Curiosity Rover at the Gale Crater. She concluded that the rock structures in the ancient lake bed looked very similar to patterns found in Australia, which were made by life forms. She stated that she hasn’t found proof of ancient Mars life, only that her hypothesis provides a compelling explanation for the formation processes behind the shapes in the surface of Mars sedimentary rock at Gale Crater.
Nofkke said, “All I can say is, here’s my hypothesis and here’s all the evidence that I have, although I do think that this evidence is a lot. In one image, I saw something that looked very familiar. 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.”
According to Noffke, if such structures do exist on Mars, then the planet may have once harbored microbial life. The microbes would have existed on Mars less than 3.7 billion years ago.
“The microbially induced sedimentary-like structures (MISS) identified in Curiosity rover mission images do not have a random distribution. Rather, they were found to be arranged in spatial associations and temporal successions that indicate they changed over time. On Earth, if such MISS occurred with this type of spatial association and temporal succession, they would be interpreted as having recorded the growth of a microbially dominated ecosystem that thrived in pools that later dried completely,” explained Noffke.
But Noffke admitted that the only way to confirm her hypothesis is to get a sample back to Earth or for the rover to do the analysis. To confirm the evidence of microbe formation, it is necessary to cut them into ultra-thin slices and carefully map the structures under microscopes. However, Curiosity is not advanced enough to do that.
NASA planetary scientist Chris McKay said, “These are just ancient sedimentary structures, and biology has long since left. A sample return mission would be the gold standard. But that’s just unlikely to happen anytime soon.”