Will the Phoenix Mars Lander find liquid water brines on Mars?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Exoscientist, Mar 13, 2008.

  1. Exoscientist Mathematician Registered Senior Member

    Experiments under Mars conditions show water could remain liquid down to -20C to -50C in salt solutions:

    Water Could Stay Liquid on Mars.
    By Bjorn Carey
    15 November 2005
    "Using a planetary environmental chamber - a tank that mimics the atmosphere, temperature, and pressure of other planets - the team exposed various concentrations of briny water to conditions that match Mars' colder, less pressurized environment. Based on these experiments, salty water, it seems, can exist as liquid on Mars.
    "It was thought that any liquid on the surface would evaporate almost immediately,' Julie Chittenden, a graduate student with the Arkansas Center for Space and Planetary Sciences told SPACE.com. 'These brine solutions enable water to stay liquid at colder temperatures. If you expose these brine solutions to cold temperatures, they can exist for a very long period of time.'
    "While pure water freezes at zero degrees Celsius, water mixed with sodium chloride and calcium chloride salts - the two salts used in these experiments - remains liquid down to -21 and -50 degrees Celsius respectively."

    The Phoenix lander is to land in the Mars north polar region. It might be thought there would be little chance for liquid water here.
    But this report shows modeled maximal temperatures on Mars according to latitude:

    Title: On the possibility of liquid water on present-day Mars.
    Journal: Journal of Geophysical Research, Volume 106, Issue E10, p.
    23317-23326 (JGR Homepage)
    Publication Date: 10/2001

    It appears in Fig. 4 on page 23,231. The maximal temperature at 70 degrees North latitude is given as 250 K, -23 C.
    This is below the freezing point of pure water but the experiments show it is in the range for liquid water brines. This fact is also discussed here:

    Making a Splash on Mars.
    "On a planet that's colder than Antarctica and where water boils at ten
    degrees above freezing, how could liquid water ever exist? Scientists
    say a dash of salt might help."
    "One thing we have to be careful of is our everyday experience that
    water always freezes at zero degrees," noted Hoover. "It doesn't.
    Water containing dissolved salts freezes at a significantly lower
    temperature. Don Juan Pond in Antarctica is a good example. It's a
    high salinity pond with liquid water at temperatures as low as -24 °

    Some images of Don Juan Pond:



    Some reports argue there is no life in Don Juan Pond but this article discusses life found on its periphery:

    An extraterrestrial habitat on Earth: the algal mat of Don Juan
    [correction of Jaun] Pond.
    Adv. Space Res. 1983; vol. 3, 8:39-42.

    Bob Clark
  2. Exoscientist Mathematician Registered Senior Member

    In addition, to the citation I gave that gives modeled North polar temperatures, this report gives actual TES measurements during Summer in Fig. 3:

    Summer season variability of the north residual cap of Mars as observed by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES).
    W. Calvin and T. Titus.
    Planetary and Space Science
    Volume 56, Issue 2, February 2008, Pages 212-22

    It shows 255K being reached as far north as 75N latitude, so would get even higher at the approx. 70N latitude of the Phoenix landing site.
    The linked image below which is a blow up of Fig.1 from the report:

    Factors Influencing the Location of Sustained Cold, Bright Spots in the North Residual Cap of Mars.
    J. M. Pocock, W. M. Calvin
    Seventh International Conference on Mars (2007), Abstract #3210

    also shows 255K being reached at 75N latitude, so even higher at 70 N latitude.

    Bob Clark

  3. draqon Banned Banned

    it isnt exactly salty on Mars...

  4. 2inquisitive The Devil is in the details Registered Senior Member

    Why do you make such a statement based on only one location?
  5. draqon Banned Banned

    it only states of an assumption of salty water. I do not disagree with you that there was most likely water on Mars, yes I do believe that Mars had water on its surface...but were are these salt results of which you speak of?


    allright I see it now, Mars Odyssey 2001 seems to suggest chloride presence...

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