Many sources indicate that there is ice water on Mars today, but it is mainly traces, here and there, but not that much.

However, solid hypothesis state that there were oceans on Mars, see Wikipedia's Mars ocean hypothesis or at least large aquifers on early Mars. They all concern early Mars so around 3.5 to 4 billions years ago. These theories suggest that Mars oceans could have formed Mesa landscapes (just likeGrand Canyon or Monument Valley).

So my question is simple, if all these hypotheses are true, where did that water go?

Is it possible that so much water could have been evacuated from the planet? I guess it would have needed A LOT of energy.

So it may have been transformed on the planet.

Is it possible that the water has oxidized iron, creating Iron oxide (ie rust) and that it is the main reason for Mars red color? The Mars ocean hypothesis page suggests some leads about the fate of that ocean, but none suggests the oxidation of iron consuming the entire oceans. Moreover, oxidation would imply the presence of water and dioxygen...

enter image description here http://en.yibada.com/articles/18182/20150309/red-planet-once-held-large-shallow-ocean-mean-positive-signs.htm


1 Answer 1


Some of the water evaporated, some of it froze and another good part of it went into the surface and is now subterranean. For more info read Mars' Vanished Water & Atmosphere --Where Did It Go? and MAVEN’s Quest – Where Did Mars Water Go?.

There's much still to learn and experiments in the future will help us to better understand the evolution of Mars' atmosphere.

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    $\begingroup$ You should clarify what you mean by evaporated. Water evaporates on Earth in vast amounts every day but Earth doesn't lose much water. There's two primary mechanisms through which Mars lost it's water. Jeans escape and being blown off by the solar wind. $\endgroup$
    – userLTK
    May 1, 2018 at 14:26
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    $\begingroup$ @userLTK thats an answer. Chop Chop $\endgroup$
    – Muze
    Mar 11, 2019 at 22:12
  • $\begingroup$ If the water evaporated or went in to space, where did the atoms of the water molecules eventually go? Mass doesn’t disappear so did these hydrogen and oxygen atoms eventually become comets? Make there to another planet, etc? $\endgroup$
    – Ryan
    Jun 24, 2021 at 20:07

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