Fossils on Mars? Geologist unearths intriguing hypothesis.
Evidence of water on Mars: Check. Organic chemistry in rock formations: Check. Methane in the atmosphere: Check. And now, fossils? Too soon to tell.
The journal Astrobiology 聽that examines Martian rock structures photographed by NASA鈥檚 Mars rover Curiosity that look strikingly like structures on Earth that are known to have been created by microbes. The paper's author, Old Dominion University聽geomicrobiologist Nora Noffke,聽has studied microbially induced sedimentary structures, or MISS, on Earth for 20 years, even finding evidence of 3.48 billion year old MISS in the Western Australia鈥檚 Dresser Formation. The outcrop on Mars is about 3.7 billion years old.
Is this proof of life on ancient Mars? No. But Noffke鈥檚 research takes the search to a new step, especially in light of the recent detection of methane and other organic molecules on Mars. Chris McKay, a planetary scientist at NASA鈥檚 Ames Research Center and an associate editor of the journal Astrobiology, offers his thoughts on .
鈥淚鈥檝e seen many papers that say 鈥楲ook, here鈥檚 a pile of dirt on Earth,鈥欌�� writes Dr. McKay. 鈥溾�楢nd because they look the same, the same mechanism must have made each pile on the two planets.鈥�
He continues: 鈥淭hat鈥檚 an easy argument to make, and it鈥檚 typically not very convincing. However, Noffke鈥檚 paper is the most carefully done analysis of the sort that I鈥檝e seen, which is why it鈥檚 the first of its kind published in Astrobiology.鈥�
Mars and Earth shared similar early histories, with Mars probably being a much warmer and聽wetter planet billions of years ago than it is today. Gillespie Lake, the part of a dry lakebed on Mars where the structures were found, endured seasonal flooding, a hypothetically perfect situation for microbes to thrive.
On Earth, shallow bodies of water contain colonies of microbes that trap and rearrange sediments into identifiable structures. These structures can be found across the Earth in a variety of formations and types, such as pockets, domes, erosional remnants, roll-ups, chips, pits, and cracks.聽
鈥淎ll I can say is, ,鈥� Noffke said in Astrobiology Magazine, 鈥渁lthough I do think that this evidence is a lot.鈥�
Noffke discusses next steps to provide proof for her hypothesis, but technology has not yet reached this stage. One important step includes bringing samples to Earth for in depth analyses, an unfeasible task. Or, better technology could be developed to enable deeper, more precise analyses of sedimentary samples on Mars.
鈥淎t this point, all I鈥檇 like to do is point out these similarities,鈥� Noffke adds. 鈥淔urther evidence must be provided to verify this hypothesis.鈥�
