Is there life on Mars?


Much to everyone’s surprise, the first few scoops the Mars Curiosity rover took with it’s SAM tool (Sample Analysis at Mars) appears to have uncovered something “interesting,” in the words of NASA officials.

NASA is tight-lipped about the discovery, at first noting it would be “one for the history books,” and then downplaying expectations by saying, “it won’t be earthshaking but it will be interesting.” They’re taking their time to validate their findings, which, despite the suspense, is a good thing.

NASA intend to make their findings public in early December.

The Gas Chromatograph-Mass Spectrometer that’s part of the SAM package is capable of distinguishing organic molecules from simpler naturally occurring molecules.

Is there life on Mars?

I hope so, but I doubt our first, shallow dig in the Martian sandpit will turn up something so significant, although I’d be delighted to learn otherwise.

In October, the results of a scientific survey of Lake Vida were published by the National Academy of Sciences.

Lake Vida sits in the dry valleys of McMurdo Sound in Antartica and is a doppelganger for the Northern regions of Mars.

Scientists found life beneath almost a kilometer of frozen ice and permafrost. At temperatures as low as -13C, the extremely salty brine is a slush devoid of oxygen and yet microbes thrive, at least 25 different species of bacteria, protobacteria and firmicutes.

Three independent lines of evidence suggest the age of this enclosed system is 2800 years. This icy reservoir last saw daylight when the Greeks conducted the first Olympics and Homer wrote the Iliad.

On one hand, the astounding resilience of microbial life on Earth raises the possibility of life thriving in the extremes of Mars, Titan, Europa and Enceladus. On the other hand, it raises some points against the possibility of life in outer space.

Lake Vida is an analog for how life could survive in the frigid extremes of outer solar system. And yet it is also highlights the tenacity of Earth microbes over abiogenesis, the ability of life to arise from inorganic matter.

In our limited experience here on Earth it seems once you’ve got life, life is easily propagated, but coming up with life in the first place, well, that’s the tough bit.

All the extremophiles discovered to date are related to each other and to other less extreme microbes in the phylogenetic tree of life. Whether we look under glaciers, in the deepest trenches some 11,000 meters beneath the ocean, or in thermal vents that would scorch your hand, all life on Earth is closely related at a genetic level.

We’re not sure where life originated on Earth, other than that it originated in an absurdly hostile environment almost four billion years ago. Since then, though, life has migrated into every conceivable nook and cranny on Earth, but life never arose again.

If other forms of life did arise on Earth, it seems they were overwhelmed by the life we see today and only one form of life has survived.

Physicist Paul Davis is an advocate in the search for a shadow biosphere, as there is the possibility that there are other lifeforms on Earth that have gone undetected up until now, but so far nothing has been found.

As it stands, though, the single, pervasive biosphere we see on Earth weakens the case for life elsewhere, as we don’t see isolated systems like the frozen Antarctic lakes developing their own lifeforms, we see “our” life spreading and thriving in these extreme niches.

What does all this mean for life on Mars? This doesn’t negate the possibility of life on Mars, but it suggests that if there is life, then like life on Earth, it probably arose under entirely different circumstances and has had to adapt to hang on in the extremes we see there today.

Given how NASA is downplaying the initial excitement around their undisclosed discovery, it seems they may have found some indicators for complex chemistry on Mars, but not organic chemistry, not living chemistry.

This may, however, lead to further discoveries that eventually answer the question about life on Mars in one way or the other.

Let’s see what Santa has in store for us this December.

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8 thoughts on “Is there life on Mars?

  1. It would be tremendously awesome if we found some form of life on Mars, especially if it were genetically different than the phyla we have on Earth. The versatility and resilience life-forms have is amazing, so it wouldn’t surprise me if we found life somewhere else in the solar system. I just hope our space exploration develops and expands fast enough for us to live that day. :)

    Great post, as usual, Peter.

    • If they have discovered organic chemistry on Mars, it’s going to be an extremely frustrating decade while we wait for a return-sample mission so the results can be scrutinized in a lab here on Earth

  2. Ever since the arsenic bacteria “science-by-press-conference” fiasco I am very reluctant to become excited by NASA’s “teasers”. It would be awesome if they found life, but then they have to make very, very sure that it is actually different from our kind of life. In my latest astrobiology class we actually talked about this. It is next to impossible to completely sterilize a rover or any other type of space probe. Most likely than not, we have already “infected” parts of our solar system. Let’s see what happens…

  3. Bowie? really?… anyway, I hope they found some reasonable evidence of life exisiting/existed there. On the matter of origins of life, I’m pretty sure if they found something and when the sample gets here, it might be contamination we take in there… or a distant relative of our extremos hehe. Crossing fingers and waiting… I really hope this is for history books and not a media sham.

    • I saw a comment from NASA that the over-enthusiastic engineer would have said anything and everything related to the Mars Curiosity rover was “one for the history books,” and that put it in perspective for me. And he’s right, Mars Curiosity is historic, just not find-life-on-first-dig kind of historic.

      Sample

      Given that this sample came from within an inch or so of the surface of a soft bed of fine-grain sand, which looks like a mini-dune/ridge formed recently by the wind, I can’t see that they’d find life there. These particles would be churned over by the wind and irradiated with solar radiation. If life exists that close to the surface, then, damn, we’ve really underestimated life on Mars. If there is life on Mars, it’s probably 10M below the surface at the permafrost boundary that we see exposed from time to time, in the salt brines we see running in gullies from just below the top of craters walls (see below).

      Martian Gullies

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