A Virginia geobiologist, who has spent the past two decades studying geological structures formed on Earth by ancient microbes, says that by looking at the images sent by NASA’s Curiosity Rover from Mars, she could identify similar structures on the Martian soil.
Nora Noffke is a geobiology researcher at Old Dominion University in Virginia and she has published her findings on-line in the journal Astrobiology in December. However, she is aware that her report remains just a hypothesis without further laboratory analysis.
“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. And because they look the same, the same mechanism must have made each pile on the two planets. That’s an easy argument to make, and it’s typically not very convincing.,”
said Chris McKay, NASA planet researcher and associate editor of the journal Astrobiology.
Nevertheless, he said that, since Mrs. Noffke’s paper was the most detailed analysis of that sort that he had ever seen, Astrobiology staff allowed its publication although the study was the first of its kind.
In her paper, Mrs. Noffke claims that sedimentary structures identified in Curiosity’s photos may suggest that ancient Mars once had microbes on its surface just as Earth did billions of years ago.
The photos in question were taken by Curiosity Rover while exploring the Gillespie Lake outcrop located in a dry lakebed located in the Gale Crater. Curiosity landed at the crater in 2012 and it is exploring it ever since. Previously sent photos from this Martian crater revealed that billions of years ago Mars was much warmer and wetter and had even rivers, streams and several ancient lakes on Gale crater’s surface.
Mrs. Noffke says that microbes usually reshape sediments in shallow waters such as lakes creating easily to recognize structures that fossilize over time. These structures are called microbially-induced sedimentary structures (MISS) and are very common on Earth. Scientists found MISS in ancient rocks all over the world.
Mrs. Noffke said, that although it is just a hypothesis, her theory might be very close to reality since she had a very extensive experience in studying MISS all over our planet. So, it is not hard for her to visually identify such structures even in a photo taken by a rover on a distant planet like Mars.
In 2013, the Virginia researcher reported the discovery of the oldest MISS on Earth (about 3.48 billion years old) in Australia. Mrs. Noffke linked those findings with the evidence of the oldest signs of life on Earth.
However, her claim that she had spotted traces of ancient life on Mars needs to get confirmed by microscopic analyses of Martian rock samples that need to be performed in a specialized laboratory on Earth. Still, returning samples to Earth is just not feasible yet.
Image Source: Astrobio.net