Anonymous asked in Science & MathematicsAstronomy & Space · 9 months ago

According to a recent paper the minimum mass for a planet to have water is 2.7 percent that of Earth so why doesn’t Mars have liquid water?

Mars is around 5 times that mass. Are they meaning if a planet had that mass but a similar density to Earth? In that case the radius of the planet would be around 35 percent that of Earth. Zero world with a radius of that can have liquid water.

8 Answers

  • 9 months ago
    Favourite answer

    If just "water" is specified, then that could be in any form - ice, vapor, or liquid.  Mars *does* have water ice, as it was discovered by the Phoenix probe years ago. 

    Liquid water wouldn't last on it's surface, as the pressure is so low it would simply boil away, and the temperature is so cold that what has boiled will freeze solid. 

  • 9 months ago

    Does it say in the paper that such planets 'must' have water ??

  • Mike
    Lv 7
    9 months ago

    Mars has no magnetic field, so nothing to protect its atmosphere from the solar wind.

    Without protection, the atmosphere was gradually blown away from the planet.

    So now Mars has too little atmosphere to keep water from sublimating to vapor and being lost to space.

  • 9 months ago

    Martian water has both sublimated and frozen over the Aons

    It is thought that 2. 5 Billion years ago Mars was a lot warmer, wetter, had internal heating which produced its Vast Volcanoes

    With more Mass, it would have had a substantial Atmosphere too

    The Tharsis Region of Mars is a Vast kidney shaped Plain the size of Texas

     A scar hewn out by a tremendous Impact

    It can explain why also get Meteorites on Earth that have originated there

    Maybe even its two Moons

    At 2. 5 Billion years ago it would have been the death knell for any Evolution that had been going on there

    Evolution began on Earth 3.8 years ago so there would have been a Hiatus there

     A little Robot Scraping the Surface does not yield a lot of Information

    But Archeologists and Geologists would find more clues

    Imagine finding a Fossil

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  • Tom
    Lv 7
    9 months ago

    You HAVE to have atmospheric pressure or any water would boil off

  • 9 months ago

    Mars has no liquid water on the surface that we have seen.  However, photos show there are soil marks on slopes that mean water flowed down recently.  So Mars does have liquid water at times.

  • Anonymous
    9 months ago

    It comes down to density. If Mars had more density and thereby more mass keeping the radius it would likely have a molten core and magnetic field this a thicker atmosphere. If a planet with a density similar to Earth with a radius of 35 percent that of Earth it could still have a magnetic field but a far weaker one. Look at Mercury for example. Place that in the habitable zone and it could have a thinner atmosphere. Remember a 1 percent atmosphere than Earth can still have liquid water. 

  • P
    Lv 7
    9 months ago

    Mars is too cold.

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