We’ve been rovering around Mars for quite some time now – in fact, the first rover, Sojourner, went into operation in 1997. Yeah, it doesn’t sound that long ago, but consider this: kids born that same year – they’re going to college now. Since we began rovering we have been developing a more detailed and accurate picture of the Mars landscape. Often, looking at these pictures can make us think…oooh, that looks like something you’d totally see on Earth…a coffin in the desert,for example.
Yet those pesky scientists urge caution, warning us that it is our own eyes trying to impose order on an alien landscape.
But the peer reviewed journal of Astrobiology has thrown caution to the wind! Or, more accurately, published the results of Professor Nora Noffke’s careful and thoughtful evaluation of digital images taken at Gillespie Lake Member, Mars. Apparently, we are pretty committed to the idea that Mars and Earth had a similar ancient history, with that important ingredient: water. Noffke basically just cites a bunch of other studies to be like, yeah, that’s a thing. So, putting aside that pesky problem, Noffke focuses her argument on explaining why morphological similarities between ancient lake beds on Earth and on Mars might prove Martians exist. Fine, it doesn’t prove Martians exist. It suggests that there was microbial activity on Mars not unlike Earth.
Why? Because the appearance of the Martian rock appears to have a structure remarkably similar to what here on Earth we call microbially-induced sedimentary structures (or MISS). Basically, in shallow pools of water (like lakes, or at the coast) a carpet of microbes traps and rearranges sediment, making a distinctive pattern. Noffke has found patterns evocative of this in the images returned by the Mars Rover. See – they are like IDENTICAL!
Fine, you’re right, we can’t tell at all. But Nora Noffke sure can. Last year Noffke detailed one of the oldest of these structures in the world, dating a MISS she discovered in Western Australia as one of the oldest signs of life in the world at 3.4 billion years old. And it was this incredibly old structure that most resembled the structure found in the ancient Martian lakebed. It apparently has all sorts of telltale signs if one knows where to look – or, more appropriately, what to look for: distinctive shapes including erosional remnants, pockets, domes, pits, chips and cracks.
Noffke is quick to tell us all that her paper doesn’t prove that life existed on Mars – it is still a hypothesis. The only way to be sure would be to physically examine a slice of Martian rock. But all studies of possible Martian life are hampered by the problem of distance and the capabilities of the Rover, which is why Astrobiology has normally chosen not publish such articles. So, extra hats off to Noffke for publishing in such a rigorous journal.
And so, today we can say definitively that there is possibly evidence of fossilized life on Mars, pending much further investigation.
Paper Citation: Nora Noffke (Dec, 2014) Ancient Sedimentary Structures in the <3.7 Ga Gillespie Lake Member, Mars, That Resemble Macroscopic Morphology, Spatial Associations, and Temporal Succession in Terrestrial Microbialites. Astrobiology. Volume 14, Issue 2
Featured Image: NASA