Life On Mars – Day 120

By Chris Thompson

Across the Margin cranks up the voltage and points its high-powered antennas towards Mars…

Curiosity, NASA’s shiny new exploration rover, has been extremely busy over the past four months. Its initial scientific discoveries have catalyzed enthusiasm for Martian exploration and captured the attention of the world. And since we last checked-in this mighty science lab on wheels has beamed back more than 25,000 images, providing us with a wealth of astonishing views from within its new home, Gale crater. From the comfort of our very own living rooms we can now channel our inner explorer and gaze excitingly upon absolutely stunning vistas, some of them eerily similar to what might be encountered on a casual visit to the Great American Southwest.

For those of you interested in the more meteorological aspects of Mars’s make-up, Curiosity comes outfitted with a miniaturized environmental monitoring station called REMS. This multifaceted climatic device has already allowed the rover, through diligent measurements of the planets daily cycles of radiation, pressure and temperature, to sniff out the composition of Mars’s gradually escaping atmosphere. Its instrumentation is so sensitive in fact that Curiosity has even been able to detect the passing signatures of numerous “dust-devils”,  powerful vortexes of fine-grained sand tearing across the crater floor.

The picture that this complex and capable rover is steadily painting is lending further evidence to the notion that the Red Planet is still very much an active and dynamic place. However, we must remember that even though all these findings and associated imagery are pleasing to look upon and scientifically relevant to the research community, their role is ancillary to Curiosity’s two-year prime mission. NASA didn’t just spend a billion dollars on this program so it could drown in an orgy of pretty pictures and weather forecasts1. It built Curiosity to ascertain whether areas inside Gale crater ever presented a habitable environment for microbes. It’s as simple as that. And at Curiosity’s disposal to achieve this goal are a myriad of fascinating scientific tools, some newly invented for this mission and others merely old standby’s either miniaturized or re-imagined for new roles.

The sum total of all this extraordinary technology is a multi-layered ability to examine the surface of Mars in incredibly fine detail, thus allowing for a systematic and methodical search for any indications that Mars could have at one time supported life2. Curiosity’s capability to detect complex organic molecules in rocks and soils is a truly spectacular quality and if found to be present these compounds could conceivably be of biological origin. With this in mind NASA set the rovers main biological objectives as follows:

(1) Determine the nature and inventory of organic carbon compounds

(2) Investigate the chemical building blocks of life on Mars (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur)

(3) Identify features that may represent the effects of biological processes (biosignatures)

Objectives one and two are extremely straightforward and should be relatively easy to assess with Curiosity’s scientific suite. Think of these goals as fundamental audits of the surrounding landscape in Gale crater. Curiosity will be able to drive up to a feature, be it a sedimentary layer deposited within the 5km tall Mt. Sharp or a piece of damp clay on the crater floor, and perform a level of chemistry on it better than any previous spacecraft. Its suite of scientific instruments will determine, element-by-element, what is truly there.

Objective three however, is a little bit harder to achieve. For one we are on an entirely different planet looking for signs of life that may have evolved in a separate and completely foreign manner from our own. So what we are looking for exactly can only be influenced by what we already know. And what we already know pretty much falls into objectives one and two. So the main challenge for Curiosity will be to find patterns in the data that represents a bone fide biosignature–some type of quantifiable mark of life that may have been produced by a living organism. This signature must be something either elemental or textural, representing some type of phenomenon, which cannot be easily explained by natural or physical processes for it to be true.

Already, this talented rover has begun to place a few of the key elements for life within Gale crater. It has established rather convincingly that its current location was once the site on an ancient streambed filled with actively running water. The activity of the water at this site was such that NASA considers the rounded stones found there to have most likely originated from outside Gale crater. Satellite imagery from the Mars Reconnaissance Orbiter illustrates that Curiosity landed in a fan of debris that was deposited at the mouth of an erosion channel descending the crater wall. Similar canyons and channels are common on Earth, indicating that Gale crater was probably a watershed in the past and quite possibly a lake.

Add to this the rounded nature of the river stones and it would be easy to suggest that the water was actively flowing into the crater for many thousands of years. From the size of gravels that the stream carried, NASA has been able to calculate that the water was moving at about 3 feet per second, and was possibly ankle to hip deep.3 The implications for this discovery are enormous as it places a key ingredient for life, water, on Mars. The notion that Mars once had a wet past has been kicked around for decades and this discovery provides a definitive, direct observation of the answer. Mars was once wet. It once had rivers and streams and most likely had lakes and a globe-spanning ocean. It’s nothing short of amazing what this rover has done in the short amount of time it has been on Mars and if last Mondays news conference at the Fall meeting of the American Geophysical Union was any indication of where we are headed then the future looks exciting!

Now I feel that before we delve into Curiosity’s most recent discoveries I should preface this discussion with some background. A bit of a primer on what is at stake here and how carefully we must discuss all this amazing science occurring one planet away. For now that Curiosity has shrugged off the rigors of space travel and gotten down to beginning its primary mission–which is good, solid, observation based science–we must understand that its discoveries, from the most trivial of concepts to those paradigm shifting ideas reserved for the “history books”, travel at exactly one speed and one speed only–the speed of science. This pace is slow. Excruciatingly slow. Painfully slow. Double quadruple check your answers slow. And this cautious and diligent pace will continue to slam right up against the ultra-fast speed of our modern world with its instant text messages, twitter updates and 24 hour cable news cycles. The potential for miscommunication here is huge and up until now NASA has been slow to acknowledge this.

The first inklings of this possibility for misunderstanding occurred late last month, when an understandably excited John Grotzinger, chief scientist for NASA’s Mars Curiosity rover, let slip to NPR reporter Joe Palca that Curiosity had made a discovery that was “gonna be one for the history books”. The media picked-up on his words and ran with it, and the wild speculating and hear-say based reporting that currently passes as journalism began. The press took Grotzinger’s words to mean that Curiosity had discovered sigs of life or life itself or an alien or whatever the modern, internet-based game of telephone morphed Grotzinger’s words to mean. And the fallout was huge. It got so bad that JPL and NASA felt they had to issue a press-release just to settle down all the rumor-mongering and wild speculation, adamantly stating that “the instruments on the rover have not detected any definitive evidence of Martian organics.”

What the public needs to understand is that there are very talented people who operate Curiosity and at the end of the day they are nothing more than scientists. Scientists driving from 154 million miles away a big, expensive, extremely well designed, SUV-sized, nuclear-powered rover across Mars that actually responds to their commands!4 And sometimes they get excited about things. Excited about the small changes that could have huge ramifications for their field. For you see, to them any bit of science is exciting and I can’t blame them for wanting to share it with the rest of us. Especially when the only other prospect is to keep quiet and slowly build your case for discovery over the next two years. It is in our scientists nature to want to share these discoveries with the world regardless of wether or not they cause the public to bubble with excitement. Unfortunately I imagine that going forward NASA will be a lot more tight-lipped and absolutely confident in their results before they go about sharing them with the rest world. Lesson learned.

We the public on the to other hand, through our burgeoning overreactions, have unwittingly demonstrated that we actually care about the work that the talented individuals at NASA and JPL are doing. And this is a good thing for it is in our nature to be curious. But I think we all need to grow up a little bit. Take a seat. Put away our smart phones and take a deep calming breath, meditating on the concept that some things take time. Especially the important endeavors like what Curiosity’s research team is currently trying to accomplish. We should all choose to learn from this patience and gain a measure of insight that the slow journey of discovery often provides us. We should not rush to sacrifice this voyage because of an impatience for a promised payout at the finish, for it is the journey itself that defines us and not where we end up. Because at the end of they day what is it that we all are really doing? We’re adding, through the travels of our individual experiences, to humanity’s collective knowledge. And that’s something that takes patience.

So with these concepts of cautious optimism and collective patience firmly rooted in our mindset we can hopefully begin to more casually examine Curiosity’s most recents findings. Monday’s news conference exhaustively covered the recent data coming out of a work site in Gale crater called Rocknest Wind Drift, a part of the larger Rocknest site. The rover worked at this location from Sol’s 56-100 and while there collected sand from a series of downwind drifts, protected there from the fast moving winds of the crater floor by an irreguar collection of dark, fragmented stones. These samples, five in total, were scooped from the sandy drifts and delivered to Curiosity’s Sample Analysis at Mars, or SAM, instrument suite, where the finely-sifted grains were heated and analyzed. Curiosity’s SAM instrument uses a tiny oven to efficiently cook dirt samples collected on Mars and it then studies the gases these samples give off in order to determine their chemical makeup.

In the five samples examined, NASA’s Mars exploration rover detected sulfur, chlorine, and oxygen compounds within the fine grains. The sulfur compounds suggest the presence of sulfates or sulfides in the grains and scientists suggested that the oxygen and chlorine may come from perchlorate, a substance also found by NASA’s Phoenix Lander in the Mars polar region. In its hunt for a definitive detection of Martian organic molecules Curiosity was not so lucky however. True, it was able to detect simple chlorinated carbons containing hydrogen, carbon and chlorine in various configurations when it heated the perchlorate’s, but more work is needed to determine if the carbon in these molecules is of terrestrial or Martian origin.

Overall NASA’s Mars rover Curiosity has discovered complex chemistry on the Red Planet, but it still remains to be seen whether the carbon it discovered hails from Mars or Earth. The SAM is an incredibly sensitive piece of machinery and it may be detecting trace amounts of carbon carried to Mars by the rover. Further testing of additional samples at this site will shed more light on the matter as Curiosity continues its tireless search for organics in the rocks and soil throughout Gale crater. We must remember that the discovery of anything is a good thing, and that the accumulation of knowledge is the greatest achievement our species can hope to achieve. I have every expectation that there are many more remarkable discoveries still to come.

  1. The weather today in Gale crater is sunny with passing high-elevation carbon dioxide clouds, a low of -86*F and a high of 37.4*F with light winds blowing out of the East []
  2. This is not to be confused with the misconception that Curiosity’s goal is to discover life. The Mars Science Laboratory is not a life detection mission although it is possible for Curiosity to detect life’s ingredients, a.k.a building blocks. Future missions such as the 2018 ExoMars endeavor will address the presence of biomaterial more thoroughly. []
  3. Fuck yeah…Science! Now that’s what I’m talking about! []
  4. It is still to this day truly extraordinary to me that we have the ability to do this kind of remote research. []

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