Water oceans on mars?, Images of different water oceans on mars based on MGS MOLA instrument. Options

[Guest_Magnus Lundstedt_*]

I have just completed a fun little afternoon project. I have long been looking for what an ocean on mars would look like for different amounts of water - preferably with a movie for many different ocean heights. So after not finding it ever, I did it myself today:

http://magnus.infidyne.com/mars/water/

[Guest_Richard Trigaux_*]

There are still many things strange and unknown about water on Mars.

For instance, if you look at Google mars you notice that huge surges of water (or at least liquid) created hyper large flow channels leading from Tharsis dome to the northern plains. The springs of these water flow are graben-like hollows which are Vales marineris itself, of parallel to it. It is really ununderstandable, it is as if there was a huge eruption of water from underground, associated with major geological features. Could magma chambers differentiate to such an extent that they contain only water? All along the southern plateau, flow marks gather water which apparently rained over this plateau, for instance Maadim Vallis, which filled the Gusev crater (Spirit landed on this filling). Other flow marks lead to Helas basin, but were apparently unable to fill it with sediments.


So whatever how this happened, it is clear that Mars, usually very dry, experienced brief episodes of flooding, and thus free liquid water on its surface, and thus a temporary atmosphere of steam. Could such an atmosphere lock Mars in a state of greenhouse heated planet? Perhaps yes, but obviously this did not happened. So in a matter of weeks, or even days, the free water was covered with ice, and likely froze to the heart in some years. Maybe this frozen ocean is still there, in the northern plains, covered with a layer of dust which prevents it from sublimating.

And steam in the atmosphere? Likely most of its molecules are broken by UV light, and hydrogen escapes. The reminder forms oxygen and hydrogen peroxyde, which are still present in Mars atmosphere today. Such an oxydizing atmosphere is the responsible of the reddish colour of Mars (by oxydizing iron).

[Guest_Magnus Lundstedt_*]

Yeah I have seen those. But what I dont understand is why it has to be "huge surges"; why not a smaller continious flow during a million years or so? (if we assume mars could have hold significant amounts of water for that long)

If mars was always very dry, one explanation can be no/little water, but could not another explanation be that while there was huge oceans for a short time and a few rivers leading out to it; verry little rain fell on the landmass resulting in a very dry (desert-like) landmass, most of the steam in the atmosphere never condesated back to rain - it just ended up beeing blown away from the planet high above the surface? Maybe the larger water-outflows from the olympus-mons area is due to increased rainfall / direct condensation on mountain walls, due to more cooling of that area during night (because of extreme altitude).

Well, what I wonder is; do we really KNOW that: (and if so how, what proofs are there?)

1) There was verry little/no water on mars surface
2) The big river-like features was formed in great surges of water (and not wind, or water during X million years?)
3) That Vales marineris was formed after water under it erupted. Cant there be other explanations for that formation, for example deformation of the planet after the evaporation of a hypothetical ocean?
4) It is not possible that entire water molecules or H + O2 molecules separateley gets blown away high above mars surface. If we would have a ground atmospheric pressure of around that of earth, on mars, I assume the highest layers of the atmosphere would be quite far away from the surface; thus the force of gravity acting on those molecules would be far lower than that force on the molecules high up in earths atmosphere. Thus solar winds might be able to blow away larger and heavier atoms/molecules?

It would be intresting if there are any papers on this matter.

[Guest_Richard Trigaux_*]

Yeah I have seen those. But what I dont understand is why it has to be "huge surges"; why not a smaller continious flow during a million years or so? (if we assume mars could have hold significant amounts of water for that long)

Why "giant surges"? because these water beds are huge, 100kms large or more, while showing erosion-sedimentation marks of a mountain torrent. So the flow was much larger than Earth's Amazon, and much faster, implying a flow rate several orders of magnitude greater than anything known on Earth. Such a flow rate would have quickly filled an ocean, so it cannot have lasted millions of years. The mystery is where this water came from, and how such a quantity made to the surface, apparently from underground. The most commonly accepted explanation is that Mars had a watertable, of a mixture of water and carbon dioxid. At the occasion of a tectonic process, the pressure released, inducing a massive boiling of the carbon dioxid and the release of a torrent of mud. Personally I add that some volcanic eruptions may have released huge clouds of steam, carbon dioxyd and dust. But until now nobody can be sure of what happened.

... I assume the highest layers of the atmosphere would be quite far away from the surface; thus the force of gravity acting on those molecules would be far lower than that force on the molecules high up in earths atmosphere.

The gravity at high altitude (100 to 300kms) is not much smaller than on the ground. The ability of a planet to retain its atmosphere depends mainly on its gravitation, but also on its temperature and composition, and in a less extent on processes like UV or solar wind (if the later is not shielded by a magnetic field).

[Guest_Magnus Lundstedt_*]

Why "giant surges"? because these water beds are huge, 100kms large or more, while showing erosion-sedimentation marks of a mountain torrent. So the flow was much larger than Earth's Amazon, and much faster, implying a flow rate several orders of magnitude greater than anything known on Earth. ...
The gravity at high altitude (100 to 300kms) is not much smaller than on the ground. The ability of a planet to retain its atmosphere depends mainly on its gravitation, but also on its temperature and composition, and in a less extent on processes like UV or solar wind (if the later is not shielded by a magnetic field).

Ah didnt realize that it was so huge, quite intresting Would be intresting with some papers that discusses this in more detail.

Ah ok on the altitude. Maybe an earth-like (pressure wise) would not extend larger than 100-300 km above surface, which maybe makes it unrealistic that huge amounts of water can have evaporated into space?