Mystery of the missing water

With enough water on Mars to form frost and clouds, direct visual evidence of water ice, and water apparently responsible for the clumpy Martian soil, one would think that there would be the tiniest bit of free water molecules not bound up in ice in the soil of Mars.

Thermal and conductivity probe

With even an extremely small amount of frozen water, it could be detected by measuring how well electricity flows within the soil. That is exactly what the Mars Phoenix Lander did by sticking electrical probes into the soil. Puzzlingly, the measurements seem to indicate that the Martian soil is extremely dry with no unfrozen water.

Where is the missing water? Is it because it's so cold and the atmosphere so thin that water molecules would immediately be bound in ice or evaporated? Or is there actually unfrozen water in the soil, but some special chemical property of the soil affects the electrical conductivity? I guess we'll hear what's likely from the Phoenix scientists soon enough.

3 Replies to “Mystery of the missing water”

  1. My hubby just said something about the gravity not being sufficient enough to cause green house heating.

  2. The smaller gravity causes more loss of atmosphere than on Earth, and that's what I thought was all to it, but with a bit of searching there turns out to be two additional factors that may be even more important. The lack of a magnetic field on Mars allows the solar wind to strip away the atmosphere, and the lack of plate tectonics (i.e. volcanoes) means that not enough carbon dioxide is replenished to compensate for the carbon trapped in rocks.

    And not so coincidentally, all three factors are due to Mars' smaller size.

  3. Stacy wrote:

    Is it posible that the water is just trapped in the atmosphere? (and dropped some on the ice cap?)

    My own guess is along the same lines, actually. What's puzzling the scientists (and me! :) is that we know there's plenty of water around the lander (and it's also pretty close to the ice caps, that's why it landed where it did), but a thin layer of unfrozen water that should be there isn't (and by thin, they're talking like one molecule thick thinness).

    I have the feeling that it's because of the extremely thin Martian atmosphere, so that any such layer will evaporate very quickly, unlike with the permafrost in Antarctica on our own Earth. I'd be wrong if the partial water vapor pressure (that is, the pressure purely due to water in the atmosphere) between the two places are comparable, though.

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