Phoenix Mars Lander Finds Surprises About Planet’s Watery Past

From a UA press release:

An instrument designed and built at the UA measured the isotopic composition of the Mars atmosphere, suggesting liquid water has interacted with the Martian surface throughout the planet’s history.

By Daniel Stolte, University Communications, and NASA’s Jet Propulsion Laboratory September 9, 2010

Liquid water has interacted with the Martian surface throughout Mars’ history, measurements by NASA’s Phoenix Mars Lander suggest.

The University of Arizona conceived of and ran the Phoenix mission, which landed near the north pole of Mars in May of 2008; it is the first Mars mission ever led by a university. Credit: NASA

The findings, published in the Sept. 10 issue of the journal Science, also suggest that liquid water has primarily existed at temperatures near freezing, implying hydrothermal systems similar to Yellowstone’s hot springs on Earth have been rare on Mars throughout its history.

These surprising results come from measurements Phoenix made in 2008 of stable isotopes of carbon and oxygen in the carbon dioxide of the Martian atmosphere. Isotopes are variants of the same element with a different number of neutrons, such as carbon-12, with six neutrons, and the rarer carbon-13, with seven.

Unprecedented precision in determining the ratios of isotopes in Martian carbon dioxide sheds new light on the history of water and volcanic activity on the surface of Mars.

The measurements were performed by the Evolved Gas Analyzer on Phoenix, part of the lander’s Thermal and Evolved Gas Analyzer, or TEGA, an instrument designed and built at the University of Arizona. TEGA’s mass spectrometer was capable of a more accurate analysis of carbon dioxide than the ones on NASA’s Viking landers in the 1970s, the only other such instruments that have returned results on isotopic composition from Mars.

This is the Thermal and Evolved Gas Analyzer, or TEGA, in action on the surface of Mars. An open door has received a sample of Martian dirt delivered by the robotic arm scoop while a closed set of doors next to it is awaiting its sample delivery. In the foreground, a corner of the box housing the mass spectrometer used to analyze the Martian atmosphere for this study is visible. Credit: Courtesy of W. Boynton/University of Arizona

“We use the TEGA instrument as a crime scene investigator,” said William V. Boynton, a professor at the Lunar and Planetary Lab in the UA’s department of planetary sciences. “Like a chemical fingerprint, isotopes tell us what process is responsible for making the material we are studying.” Boynton, who heads the group that built the TEGA instrument, co-authored the Science paper.

Carbon dioxide makes up about 95 percent of the Martian atmosphere. NASA’s Mars Exploration Program has put a high priority on learning more about the isotope ratios in Martian carbon dioxide to supplement the information from Viking and from analysis of meteorites that have reached Earth from Mars.

For the measurement, the TEGA instrument on the lander opened a pin-point-sized hole while a vacuum sucked a puff of Martian atmosphere into its chamber for isotope analysis.

The analysis revealed that carbon dioxide on Mars has proportions of carbon and oxygen isotopes similar to carbon dioxide in Earth’s atmosphere. This unexpected result reveals that Mars is a much more geologically active planet than previously thought. In fact, the new results suggest that Mars has replenished its atmospheric carbon dioxide relatively recently, and that the carbon dioxide has reacted with liquid water present on the surface.

“Atmospheric carbon dioxide is like a chemical spy,” said Paul Niles, a space scientist at NASA’s Johnson Space Center in Houston and lead author of the paper. “It infiltrates every part of the surface of Mars and can indicate the presence of water and its history.”

The low gravity and lack of a magnetic field on Mars mean that as carbon dioxide resides in the atmosphere it will be lost to space, a process that favors loss of the lighter carbon-12 isotope compared to carbon-13. Although an older atmosphere on Mars should contain much more carbon-13, it doesn’t. This suggests that the Martian atmosphere has been recently replenished with carbon dioxide emitted from volcanoes, and volcanism has been an active process in Mars’ geologically recent past.

Another clue comes from the second element that makes up carbon dioxide: oxygen. Oxygen, like carbon, comes in different isotopes: oxygen-16 and the heavier oxygen-18.

The team compared the results from Phoenix to measurements obtained from Martian meteorites that were hurled into space from the Red Planet’s surface during impact events and eventually fell onto Earth where they were later collected. The meteorites contain carbonate minerals that form only in the presence of liquid water and carbon dioxide.

“Carbon dioxide spewed into the atmosphere by volcanoes is very similar in its oxygen isotope ratio to that found in rocks,” said Boynton. “But we see a big difference between the oxygen ratios of the volcanic rocks and the atmosphere.”

This suggests that the carbon dioxide in the volcanic rock of Martian meteorites has reacted with liquid water, enriching the oxygen in carbon dioxide with heavier oxygen-18.

The comparisons of isotopes in Mars’ atmosphere with those in the meteorites provide confirmation of key findings. For example, one meteorite that crystallized during recent geological time on Mars – about 170 million years ago rather than billions of years ago – has carbonates with isotopic proportions that match the atmospheric measurements by Phoenix.

According to Niles, the isotopic signature indicates that liquid water has been present on the Martian surface recently and abundantly enough to affect the composition of the current atmosphere. It also reveals the water has primarily existed at temperatures near its freezing point.

The results provide supporting evidence that the watery conditions associated with carbonate formation have continued even under Mars’ current cold and dry conditions.

“This shows that the carbonates formed under the influence of water and the atmosphere in the recent geologic past,” Boynton said.

Niles added: “The findings do not reveal specific locations or dates of liquid water and volcanic vents, but geologically recent occurrences of those conditions provide the best explanations for the isotope proportions we found.”

The University of Arizona conceived of and ran the Phoenix mission, which landed near the north pole of Mars in May of 2008; it is the first Mars mission ever led by a university. The Principal Investigator is Peter H. Smith, a professor at the UA’s Lunar and Planetary Lab. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., provided the management of the project. For his leadership on the TEGA project, Boynton was recently honored with NASA’s Exceptional Public Service Medal.


28 thoughts on “Phoenix Mars Lander Finds Surprises About Planet’s Watery Past

  1. Question
    What temperature would the martian atmosphere have to be for liquid water to exist? Given the low atmospheric pressure there.

  2. According to Niles, the isotopic signature indicates that liquid water has been present on the Martian surface recently and abundantly enough to affect the composition of the current atmosphere. It also reveals the water has primarily existed at temperatures near its freezing point.
    So after the aliens completed their long transformation of Earth into something that would yield intelligent life similar to themselves, they obliterated the telescopically-visible evidence of their work on Mars?
    They were likely still horribly embarrassed after screwing up Venus so badly. Oh well, with engineering and design work you do end up with unusable prototypes. Good thing they got it on the second try, Mars would have been much harder. And with Earth a success, there was no need to preserve the preliminary efforts on Mars. Best to not have the rapidly-developing new intelligent life wonder who’s doing what one planet over.

  3. Isn’t the carbon isotope ratio in CO2 that ‘proves’ that man is increasing the atmosphere’s CO2? Doesn’t this result shake the assumptions that lead to this ‘result’?

  4. I remember being surprised at one of the first images from underneath the Lander. I have digitally enhanced a section of it here –
    However an inquiry to the Phoenix team at the time received a response that the image was inconclusive with regard to liquid water –
    -Thanks for your interest in the mission and sorry for the long delay in our response. At this writing speculation varies–unfortunately we can’t sample it, and it’s hard to tell just from images. It may be composed of particles of Martian soils and salts, partially liquidized in the landing and subsequently solidified, condenses or crystallized after being ejected onto struts.-
    Later images of frost subliminating from sampling scrapes seemed to provide more conclusive evidence. I visited the Phoenix site most days during the first weeks after landing. I remember wishing the screens on the sample ports had been designed for muddy soil. The Phoenix mission was very engrossing. The image captured from the mars orbiter of the lander descending on its’ main chute is a keeper.

  5. M White said September 13, 2010 at 12:30 am:

    What temperature would the martian atmosphere have to be for liquid water to exist? Given the low atmospheric pressure there.

    According to Wikipedia:

    Liquid water cannot exist on the surface of Mars due to its low atmospheric pressure, except at the lowest elevations for short periods.[42][43] However, the two polar ice caps appear to be made largely of water.[44][45] The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 meters.[46] A permafrost mantle stretches from the pole to latitudes of about 60°.[44]

    Water on Mars entry:

    Current conditions on the planet surface do not support the long-term existence of liquid water. The average pressure and temperature are far too low, leading to immediate freezing and resulting sublimation.

    Back at the first entry, we find this about the atmosphere:
    Surface pressure: 0.636 (0.4–0.87) kPa
    Composition: 210 ppm water vapor
    Thus the question seems moot. There could be a surge from an underground reservoir, perhaps some condensation, but not enough liquid water existing long enough to matter.
    Interesting planet. Fertile soil for plants, if there was water and a suitable atmosphere, and a little more warmth. Looks like there’s enough water. Just needs a denser atmosphere. So if we drop enough nuclear bombs on the surface to melt the rust and liberate the oxygen, by the time the radiation fades the atmosphere will be settled down and then…

  6. There’s nothing particularly surprising about these results; we’ve known since the seventies that Mars has had flows of liquid water at the surface, and that it is geologically active. The isotope evidence suggests that this may have been happening more recently than was previously known, and that there is still substantial release of CO2 from the regolith or volcanic sources.
    The “dewdrops” on the landing strut are interesting. Is there a later image of the same area? If the drops are water, they could be expected to change – evaporating, growing, running down the strut, and freezing – according to time of day and weather c0nditions. If they are melted minerals from the soil (which seems unlikely to me), they would not change. The subliming frost could be either water or CO2.


    The Salty Tears Of Phoenix Show Liquid Water On Mars
    by Staff Writers
    Ann Arbor MI (SPX) Mar 19, 2009
    Salty, liquid water has been detected on a leg of the Mars Phoenix Lander and therefore could be present at other locations on the planet, according to analysis by a group of mission scientists led by a University of Michigan professor. This is the first time liquid water has been detected and photographed outside the Earth.

    Has animated pic, link to larger pic.
    May 26th 2009

    More Researchers Say Liquid Water Present on Mars Now
    Finding perchlorates on Mars was not only surprising for the Phoenix lander science team, it also has created a bit of a rift among the researchers. In March, Ian reported on one scientist who used strictly photographic evidence to say that blobs appearing on the lander’s legs were actually water. Other scientists, however, including principal investigator Peter Smith were dubious about the “water on Mars now” claims. But now, a group of researchers at the University of Arkansas say they have now demonstrated a potential stable liquid on present-day Mars in the immediate environment of the lander.
    The extreme temperatures found on Mars typically lead to either crystallization or evaporation of water, making it difficult to imagine that water could be found in liquid form. However, salts have been shown to lower the freezing point of water – which is why street crews use salt on the roads to melt ice, Hanley said. Some salts, like perchlorates, lower the freezing point substantially. It turns out that the temperature for the liquid phase of magnesium perchlorate – 206 degrees Kelvin – is a temperature found on Mars at the Phoenix landing site. Based on temperature findings from the Phoenix lander, conditions would allow this perchlorate solution to be present in liquid form for a few hours each day during the summer.

    Same animated pic but larger, also a “pulled back” shot showing the full under-lander view.
    So a particular sort of salty liquid water can exist on Mars, at least as droplets, for a little bit of time for a tiny part of the year.
    Wonderful. These dang Martian landers are problematic enough to design and get delivered to the surface, and now they also have to figure in salt water corrosion resistance?!

  8. kadaka (KD Knoebel)
    Many thanks for the links. I now see I was not too far of the mark. I had not previously seen the subsequent images of additional water droplets. I believe the photographic evidence for salty liquid water on the Lander leg in the animation would be even more compelling if the images had been expanded 4 pixels to 1 or 9 pixels to 1 before processing.
    Way OT. Do any of the old grumpy guys of the skeptic community know how to get photostyler 2.0 SE running under windows 7. It was raw, but I miss it 🙁

  9. el gordo says:
    September 13, 2010 at 1:03 am

    I was amused by the NASA astronomy picture of the day (30 August) because the blurb was saying how dry Mars is and then I had a closer look. No, it couldn’t be.

    Nice photo, but I missed your point. I found which describes the Comanche outcrop rocks and their carbonate content.
    kadaka (KD Knoebel) says:
    September 13, 2010 at 4:02 am
    I hadn’t seen those water droplet photos before, thanks. Guess it’s also confirmation I spend too much time reading WUWT….

  10. From: Konrad on September 13, 2010 at 4:44 am

    Way OT. Do any of the old grumpy guys of the skeptic community know how to get photostyler 2.0 SE running under windows 7. It was raw, but I miss it 🙁

    Well, I’m running (free) Debian Linux and use (free) GIMP for image work, as far as I know how to do such.
    However, if you had Linux, which could be dual-boot on a Windows box, then you could run Wine, the Windows-on-Linux not-exactly-an-emulator (read this), which can “emulate” older Windows versions all the way back to Win 2.0. Then you should be able to run your old Windows program.
    For true masochists, or the very desperate, I have heard there are programs that will let you run Linux while running Windows. So, Win 7 to Linux to Wine to Your Old Program.
    Obligatory Links:
    (note that GIMP and Wine come with the Debian distribution)
    GIMP for Linux (currently use)
    GIMP for Windows (have used)
    Wine project home page (currently use)
    Cooperative Linux aka coLinux – just Googled it, “…the first working free and open source method for optimally running Linux on Microsoft Windows natively.” Home page says it works on Windows 2000, XP, Vista, and 7. Haven’t tried it myself, but what the heck, it’s free. Worth a shot.

  11. Talking of Co2, Mars and fuel:

    CO2 rocket could fuel return missions from Mars
    11 August 2010
    “Hertfordshire University is developing a carbon-dioxide-fuelled rocket that could help solve the problem of how Mars missions return to Earth.
    Researchers at the university hope that by September they will have built and tested the first rocket demonstrator powered by reacting carbon dioxide with aluminium.”
    The Engineer
    University of Hertfordshire

  12. Regards water in a low pressure atmosphere.
    Water can exist in its super-cooled liquid state down to very low sub-zero temperatures. So I presume it is possible that those droplets on the lander leg could be super-cooled droplets of liquid water that have condensed out the atmosphere (they certainly look like it). (The heat of the lander initiating some convection and water-vapour from the frozen earth beneath it.)
    This is the same as super-cooled droplets condensing out the upper atmosphere on earth, in lenticular clouds (and then stick on our wings). Liquid water at minus -35 oc is quite normal – our rules say it stops being liquid at -45 oc.
    But if you disturbed the droplets, they would freeze instantly.

  13. This suggests that the Martian atmosphere has been recently replenished with carbon dioxide
    All they have to do now is to find a SUVs’ cementery 🙂

  14. Is it too much to be a contrarian?
    There are a number of assumptions that go into the finding.
    Also, human nature should be taken into account.
    Regarding human nature:
    We know the great quest of those exploring Mars (by remote and in situ means) has been to find water and more specifically evidence of liquid water on the surface so it can be declared “Mars and Earth have something in common”, and that “life was possible on Mars” at least sometime in the past.
    (So, as to generate interest in projects, and, thus, funding.)
    People tend to find what they are looking for whether it is there or not — it’s call confirmation bias.
    In regards to the assumptions:
    The assumption is that there is only one way these isotopes of carbon and oxygen can form and that is in the presence of liquid water, but is that confirmed. Mars is very different from Earth in many ways. Could it be that how various isotopes are formed is different from Earth because the environment of Mars is significantly different from Earth?
    And in a slightly different vein, could this water of been formed or existed below the surface, only to quickly evaporate when expelled to the surface?
    Liquid water on the surface of Mars would take a dramatic change from present Mars dynamics. What would those dynamics possibly be?
    Now, this announced finding could well be entirely correct, but applying reasonable scepticism requires exploring possible reasons why the finding may not be correct.
    Too many times, Grand & Glorious conclusions are announced by scientists and the general public buys in without questioning the basis of the conclusions.
    Didn’t we see that in the AGW debate?
    “Just saying.” 🙂

  15. Does anyone else get the impression that this article was written by someone who does not understand what they are writing about, but they think they do?
    The logic as presented just does not hold up.
    Volcanic Atmospheric CO2 = Volcanic Rock CO2
    Volcanic Rock CO2 != Atmospheric C02
    Therefore Volcanic Rock CO2 has reacted to water and changed the atmospheric CO2

  16. Unfortunately our ability to predict climate right here on the planet we inhabit is not much superior to our skill at predicting what is going on regarding interplanetary bodies. Every time we visit one of our neighboring planets, their moons or an asteroid or comet we find that our theories of their compositions and histories are incorrect. I am sure that the computer models used are equivalent in quality in both cases.

  17. What is predictable: Martian CO2 found to have terrestrial origin
    This is quite logical as there is neither life on mars nor any SUV’s on sight.

  18. My limited understanding is that the natural sky color as seen from Mars’ surface is indigo-blue, not the bright blue we have here on earth. Martian sky can appear orange, but only during the massive dust storms that occasionally erupt there. And yes, it is contriversial how the color calibration came out on some of the images from Mars landers.
    Dr Watson says:
    September 13, 2010 at 7:23 am
    I just wish they could decide what color the Martian sky is.

  19. Enneagram said on September 13, 2010 at 7:48 am

    This suggests that the Martian atmosphere has been recently replenished with carbon dioxide
    All they have to do now is to find a SUVs’ cementery 🙂

    Umm, it’s been awhile since those SUV’s roamed the Martian countryside, the planetary surface has a top layer of rust… Hello! You have found the cemetery!

  20. @James F. Evans – Being a scientist, I have to agree with you. The ‘search for water/life’ has always been a bit disingenuous to me. Maybe the people in charge at NASA are truly motivated to find liquid water somewhere else in the universe. But, like I tell my astronomy students: the only reason a scientist needs to study Mars is to learn something new. And going by the reaction of my students, I don’t know that NASA’s effort to popularize martian exploration under the umbrella of “the search for life elsewhere” is very successful. Most of the students and scientists I know would want to study Mars anyway. Personally, I support exploring Mars for a very simple reason: because it’s there. And those who think planetary exploration is a waste of time, effort and money are not convinced by the “search for life” directive.
    Personally, if life did arise by natural causes, it is such an unlikely occurrence that I consider it a bit ridiculous to couch everything in the language of the “search for life elsewhere”. Not that I want to have that debate any time soon…

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