Got Water?

Sue Smrekar
by Sue Smrekar
Deputy Project Scientist - Mars Reconnaissance Orbiter

A theme of Mars exploration is “Follow the Water,” since understanding the history of water on our planetary neighbor will help us understand if there were environments favorable for life to occur and how climate has changed over time. This is because all life on Earth requires water and we assume the same applies elsewhere in the universe. The Mars Reconnaissance Orbiter has made numerous discoveries that have provided new insights into past wet environments on Mars, water vapor in the planet’s current atmosphere and ice in the subsurface. However, so far, liquid water remains elusive.

The Shallow Radar, or “SHARAD” instrument is the only one on the Mars orbiter that was designed with a goal of discovering liquid water below Mars’ surface. This ground-penetrating radar instrument, which was supplied by the Italian Space Agency, transmits a radar signal at approximately 20 megahertz, and receives any radar waves that bounce off the surface or subsurface layers. The radar instrument has sufficient strength to see layers to a depth of about one kilometer (a little more than one-half mile), and even deeper in the polar caps. Layers in the subsurface reflect the radar wave if there is sufficient contrast in their dielectric properties (their bulk electrical properties), as for example between dry sand and ice-filled sand. Water is a much better conductor than other geologic materials, and thus should be readily detected if present.

Image taken from NASA's Mars Reconnaissance Orbiter
This image from NASA’s Mars Reconnaissance Orbiter shows gully channels in a crater in the southern highlands of Mars.The gullies emanating from the rocky cliffs near the crater’s rim (upper left) show meandering and braided patterns typical of water-carved channels. Image credit: NASA/JPL/University of Arizona

Of all the features believed to be formed by water on Mars, we have found only two gullies known to have recent flows – within the last 5-10 years. Gullies are narrow channels that emanate from cliff walls, starting well below the local ground surface. Dr. Michael Malin used the Mars Orbital Camera on Mars Global Surveyor to repeatedly image these features because of their fresh, unweathered appearance. These efforts led to the discovery of the two relatively new gullies.

To date, the Shallow Radar instrument’s observations of dozens of regions containing gullies show no evidence of liquid water. Since slopes of the cliffs where the two new gullies occur are extremely steep, some scientists put forth an alternate hypothesis in which dry debris tumbling downhill could have formed the latest channels. Yet many of the features observed at these and other gullies strongly suggest that liquid water had at least some role in carving the channels. These channels may have formed when a past climate change caused subsurface ice to melt. Or perhaps liquid water was trapped in a past aquifer. But for now, liquid water, if it exists today on Mars, remains out of reach of the Mars Reconnaissance Orbiter.

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    13 Responses to “Got Water?”

  1. Rick Salas Says:
    May 25th, 2009 at 5:33 pm

    Hi Sue, I was just checking out some subjects I’m interested in and found some amazing things going on with exploration on Mars. It’s so interesting learning what is involved and what this could do for life here on Earth. We are learning so much. You guys are truly appreciated by many.

  2. simo Says:
    May 26th, 2009 at 7:31 am

    What if the water is liquefied locally either by local or global environment change (mechanical, temperature, chemical …) thus generating a local and temporary phenomena? In this case it would be extremely difficult to observe liquid water “in action”, but channels presence can still be explained by liquid water flows. As a matter of fact, this hypothesis can be tested by a not so difficult experiment … well, at least for someone having access to the Mars surface :)

    Smrekar says: Hi -
    Thanks for comments! Some replys:
    One possibility is certainly that something temporarily allows liquid water to flow. A leading idea is that either warm summer sunshine at just the right place might allow ice to melt briefly. Enough salt trapped in the ice would help decrease the melting temperature. Changing climate on Mars can certainly help make ice deposits unstable. The channels we see may have formed under past climate conditions, with only dry avalanches forming the recent ‘flows’.

  3. Jerry Fox Says:
    June 1st, 2009 at 1:06 pm

    The picture you post shows very clear-cut channels. Is there any info on how much the landscape is changed by the periodic dust storms? I notice no craters on this landscape, either. So is there any

    reason why the channels might not have been cut in, say, the last 10 years? The winds would surely dry the surface to a good depth quite quickly.

    Of course the real (and unfortunately impractical) experiment would be to take a few gallons of water and spray them on the surface - and sit back and watch what happens.

    Smrekar says:
    Hundreds of images are taken each year of gully sites with the hope of seeing changes. Although we don’t expect to see anything in action (any liquid water would sublimate or freeze within an hour or so, depending on the volume) we are trying to understand the rate at which new gullies form and what are their characteristics. Several new gully flows have formed in the last 10 years. At each new site we can calculate determine the shape of the channels, the slope where they form, monitor changes in color due to dust accumulation, and look for the presence of unusual composition such as salts. This ongoing study will help us better understand the role of water.

  4. Tim Jago Says:
    June 3rd, 2009 at 11:44 am

    Hi Sue,
    Fantastic job you and the team are doing. How much research time is being devoted to tracking the flow, trying to catch it in action? Would the seasons be a factor at the latitudes involved, sublimation? Sorry for the questions but you got me going with this one. Tim

  5. BA Nathan Says:
    July 4th, 2009 at 10:13 pm

    Please tell us more about August 27th 2009 and Mars as I understand it will be very close to earth and we will have an opportunity to see it on that night but I do not have a time- I understand it will be as bright as the moon and almost as big- It will be another what 800 years before that happens again. Where do we go for more information- Where do we look in the sky?

  6. Scott Mendelson Says:
    July 19th, 2009 at 10:06 am

    It would seem that if the seemingly new gullies were formed by avalanches of dry material, changes in structures i.e., loss of volume, should be visible from fyrther uphill from where the material fell, and increases in volume should be visible at the end of the gullies where material would accumulate. Is this the case? Would liquid water carry down enough rock and dust with it to confound this conclusion? Great work! I envy you!

  7. maurice smook Says:
    August 25th, 2009 at 10:26 am


    In early July I was viewing the yahoo news and one of the stories was about the Mars orbiter discovering liquid water this martian gorge. The geographical area of this liquid water sighting was the size of lake Erie or Michigan?. I have checked Nasa’s web site and nothing on about this discovery. If there is liquid water of that magnitude within the martians surface it would be major break through knowing that some life can be sustained on Mars. .

    If it is true that the obiter has detected liquid water within the martians surface it would be the scientists dream, I

    watch nasa tv and nothing has ever been televised regarding about any major discovery of any liquid water within the martians surface.

    I am just curious whether the orbiter has detected this body of liquid water within the martians surface or was it just someone dreaming this story.

    Sue Smrekar says;

    There has not been any observation of liquid water on the surface of Mars by the Mars Reconnaissance Orbiter or any other Mars orbiter. One tantalizing suggestion for brief occurrences of small amounts of liquid water has come from orbital observations of fresh gully deposits that might have been left behind by brief flows of water from underground layers of ice or deep aquifers, but alternative theories have also been offered for those fresh deposits.

  8. Robert M Blevins Says:
    September 6th, 2009 at 4:54 pm

    From your blog post: ‘Of all the features believed to be formed by water on Mars, we have found only two gullies known to have recent flows – within the last 5-10 years…’

    Where can these pictures be found? I think I’ve seen the crater-wall one, with the images taken in 1999 and 2005. But I thought there was another that showed recent upwelling on the surface of the ground. This picture was taken of a sandy area where the flow fanned out for a short distance, and then stopped, (sublimation or evaporation).

  9. Robert M Blevins Says:
    September 11th, 2009 at 9:32 pm

    Hello Sue,
    One more quick question. According to a 2006 PDF issued by JPL/NASA/San Jose State University/ and Lockheed Martin, there is a DRM decided upon for a manned mission to Mars, with the actual landing tentatively set for April 15, 2025. This document is still active at the JPL website. It describes a mission with six crew, two cargo modules (MAV on the surface waiting, one module with the MEV lander and a habitat waiting for the astronauts in orbit) Key to this plan is the use of the ISS and the Russian Energia heavy-lift booster to get the components to the ISS for the Trans-Mars Injection.

    Is this plan still valid? Are we going to Mars in 2025? The PDF says the chosen landing site is Chryse Planatia at the Viking 1 site. The length of the surface mission is listed at between 62-565 days, depending on whether or not the MAV’s methane-fuel production system is deemed operational when the astronauts arrive.

    I think the following link is okay, since it goes to the JPL document and nowhere else. I referenced it so you can have a look. It has pictures, as well as the entire mission plan from start to end, with dates.

    Sincerely, Robert

    Guy Webster, JPL’s Mars media relations specialist, responds:

    Various proposed designs have been developed for human missions to Mars, such as the hypothetical mission described by the Lockheed Martin and San Jose State University authors of that presentation for a 2006 workshop. There has not been approval or scheduling for an actual human mission to Mars.

  10. water properties Says:
    September 18th, 2009 at 6:11 pm

    water properties…

    Your topic Greenversations Saving Some For The Fishes And Rethinking The Future of … was interesting when I found it on Friday searching for water properties…

  11. Aishwarya Says:
    April 23rd, 2011 at 9:00 am

    Hi Sue,

    I have a question on temporary formation of Liquid water on Mars. Mars has strong dust storms and these dust storms must have capability to cause radiative heating of the surface. Can this process lead to formation of liquid water?

    Has NASA worked on the radiative effects on Dust particles on the surface and sub surface ICE? Can you suggest me some reading material on this topic?

    Thank you,
    Have a great day!

  12. haris Says:
    July 20th, 2011 at 10:23 am

    hi sue! i am very much interested in astrology .you guys are realy good.hats off to you

  13. Chris Landau Says:
    February 3rd, 2012 at 1:09 pm

    I can only suggest that large volumes of water, carbon dioxide and methane are released periodically from within Mars into the atmosphere via volcanic eruptions from Mons Olympus and the other volcanoes of the Tharsis Bulge. These planetary wide deluges must be absorbed or lost to space through sublimation.

    There is probably a cyclical pattern tied to strong magnetic storms from the sun. Greater volcanic eruptions will be tied to greater magnetic field induction correlation to the sun. These volcanic periods should also correlate to the Earth’s great magma flows and magnetic field reversals. The sharpness of these scoured river channels, knowing that there is active wind erosion taking place today, would suggest major rain storms within the last 2000 years and probably more recent than that are taking place. So when the next really big planetary eruption occurs, look forward to the next planetary flood. This theory best fits the obvious planetary wide river channels that are present, that have repeatedly eroded the landscape,but have left us with no visible water.

    The problem is, is that The Mars Magnetic Dynamo has shut down (no magnetic field) and only when that restarts can volcanism start up again. I think that Mons Olympus and the other volcanoes are preventing the “Martian Van Allen Belts” from forming by their very height, they are short circuiting the electrical field to Mars. Without this electrical field, there can be no magnetic field, no dynamo effect, no internal heating of the planet, no continental drift and no permanent water on the surface, from permanent rainfall. Erratic rainfall every few thousand years in large scale planetary eruptions will just not give us permanent water.

    Weak lightning storms should be occurring on Mons Olympus today as proof of this idea and geomagnetic planetary maps, concentric around these peaks should provide further proof of the idea.

    Any suggestions for leveling or insulating the volcanoes or restarting the martian magnetic field? Diamagnetic carpeting?

    Chris Landau (geologist)

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