<p>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 <a href="http://www.dailygalaxy.com/my_weblog/2011/08/-mars-vanished-water-atmosphere-where-did-it-go.html" rel="noreferrer">Mars' Vanished Water &amp; Atmosphere --Where Did It Go?</a> and <a href="http://www.universetoday.com/106297/mavens-quest-where-did-mars-water-go/" rel="noreferrer">MAVEN’s Quest – Where Did Mars Water Go?</a>.</p>

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

CC BY-SA 3.0
2018-05-01T14:26:40.850Z
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.
userLTK
CC BY-SA 4.0
2019-03-11T22:12:33.313Z
@userLTK thats an answer. Chop Chop
Muze
CC BY-SA 4.0
2021-06-24T20:07:44.477Z
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?
Ryan
CC BY-SA 4.0
2024-04-19T16:24:07.413Z
@Ryan That sounds like an excellent question to post! I will say that solar wind is going to probably ionize the atoms so they won't really be in a state to react with each other much.
Darth Pseudonym
CC BY-SA 4.0
2024-04-21T05:11:53.513Z
@DarthPseudonym can you explain more? For example, let’s say an astronaut on a spaceship traveling to Mars throws a bucket of water out in to space. I’m guessing the liquid would quickly turn to gas due to loss of pressure. Are you suggesting that solar radiation will separate the H2O so then there will be seperate H and O atoms floating around?
Ryan
CC BY-SA 4.0
2024-04-21T14:54:05.450Z
For some of it, eventually, yes. That's what ionizing radiation does, it's called radiolysis. (I should have said solar *radiation* will ionize the atoms, not the wind itself.) But more to the point, solar wind erosion of the atmosphere is, as far as I'm aware, primarily going to affect individual ionized atoms, so it's more that water molecules get high enough up to get radiolyzed, and then some of the ions produced can get blasted off by electromagnetic interactions with solar wind. At least that's what I understood from MAVEN's findings.
Darth Pseudonym
CC BY-SA 3.0
2013-12-10T20:02:59.793Z
2018-05-01T12:17:18.497Z
2018-05-01T12:17:18.497Z
Eduardo Serra
<p>Many sources indicate that there is <a href="http://en.wikipedia.org/wiki/Martian_polar_ice_caps" rel="nofollow noreferrer">ice water</a> on <a href="http://en.wikipedia.org/wiki/Mars" rel="nofollow noreferrer">Mars</a> today, but it is mainly <a href="http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Water_ice_in_crater_at_Martian_north_pole" rel="nofollow noreferrer">traces</a>, here and there, but not that much.</p>

<p>However, solid hypothesis state that there were oceans on Mars, see Wikipedia's <a href="http://en.wikipedia.org/wiki/Mars_ocean_hypothesis" rel="nofollow noreferrer">Mars ocean hypothesis</a> or at least <a href="http://www.esa.int/Our_Activities/Space_Science/Results_from_Mars_Express_and_Huygens/Mars_Express_evidence_for_large_aquifers_on_early_Mars" rel="nofollow noreferrer">large aquifers on early Mars</a>. 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 like<a href="http://en.wikipedia.org/wiki/Grand_Canyon" rel="nofollow noreferrer">Grand Canyon</a> or <a href="http://en.wikipedia.org/wiki/Monument_Valley" rel="nofollow noreferrer">Monument Valley</a>).</p>

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

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

<p>So it may have been transformed on the planet.</p>

<p>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 <a href="http://en.wikipedia.org/wiki/Mars_ocean_hypothesis#Fate_of_the_ocean" rel="nofollow noreferrer">fate of that ocean</a>, but none suggests the oxidation of iron consuming the entire oceans. Moreover, oxidation would imply the presence of water and dioxygen...</p>

<p><a href="https://i.sstatic.net/PKeNw.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/PKeNw.jpg" alt="enter image description here"></a>
<a href="http://en.yibada.com/articles/18182/20150309/red-planet-once-held-large-shallow-ocean-mean-positive-signs.htm" rel="nofollow noreferrer">http://en.yibada.com/articles/18182/20150309/red-planet-once-held-large-shallow-ocean-mean-positive-signs.htm</a></p>

CC BY-SA 4.0
2020-03-01T11:42:44.913Z
Related: https://astronomy.stackexchange.com/q/32484/16685
PM 2Ring
<mars><water>
Where did Mars' water go?
Thibault
# Where did Mars' water go?

(Asked by: username_0 on 2013-12-10)

Many sources indicate that there is [ice water](http://en.wikipedia.org/wiki/Martian_polar_ice_caps) on [Mars](http://en.wikipedia.org/wiki/Mars) today, but it is mainly [traces](http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Water_ice_in_crater_at_Martian_north_pole), here and there, but not that much.

However, solid hypothesis state that there were oceans on Mars, see Wikipedia's [Mars ocean hypothesis](http://en.wikipedia.org/wiki/Mars_ocean_hypothesis) or at least [large aquifers on early Mars](http://www.esa.int/Our_Activities/Space_Science/Results_from_Mars_Express_and_Huygens/Mars_Express_evidence_for_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 like[Grand Canyon](http://en.wikipedia.org/wiki/Grand_Canyon) or [Monument Valley](http://en.wikipedia.org/wiki/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](http://en.wikipedia.org/wiki/Mars_ocean_hypothesis#Fate_of_the_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](https://i.sstatic.net/PKeNw.jpg)](https://i.sstatic.net/PKeNw.jpg)
<http://en.yibada.com/articles/18182/20150309/red-planet-once-held-large-shallow-ocean-mean-positive-signs.htm>

**Tags:** mars, water
> **Comments:**
> **username_1**: Related: https://astronomy.stackexchange.com/q/32484/16685  

---

## 1 answers

### Answer by username_2 on 2013-12-10. Score: 10 | Accepted answer

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?](http://www.dailygalaxy.com/my_weblog/2011/08/-mars-vanished-water-atmosphere-where-did-it-go.html) and [MAVEN’s Quest – Where Did Mars Water Go?](http://www.universetoday.com/106297/mavens-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.

> **Comments:**
> **username_3**: 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.  
> **username_4**: @userLTK thats an answer. Chop Chop  
> **username_5**: 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?  
> **username_6**: @Ryan That sounds like an excellent question to post! I will say that solar wind is going to probably ionize the atoms so they won't really be in a state to react with each other much.  
> **username_5**: @DarthPseudonym can you explain more? For example, let’s say an astronaut on a spaceship traveling to Mars throws a bucket of water out in to space. I’m guessing the liquid would quickly turn to gas due to loss of pressure. Are you suggesting that solar radiation will separate the H2O so then there will be seperate H and O atoms floating around?  
> **username_6**: For some of it, eventually, yes. That's what ionizing radiation does, it's called radiolysis. (I should have said solar *radiation* will ionize the atoms, not the wind itself.) But more to the point, solar wind erosion of the atmosphere is, as far as I'm aware, primarily going to affect individual ionized atoms, so it's more that water molecules get high enough up to get radiolyzed, and then some of the ions produced can get blasted off by electromagnetic interactions with solar wind. At least that's what I understood from MAVEN's findings.  

---

