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Posted by: Magnus Lundstedt Mar 14 2006, 11:20 PM

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/

Posted by: ElkGroveDan Mar 15 2006, 01:36 AM

Nice. Now if you really want to impress us, project it on a rotating globe

Posted by: RNeuhaus Mar 15 2006, 01:56 AM

Very interesting pictures and these give us the idea where is low and high. Very good Mars altitud view.

Rodolfo

Posted by: Magnus Lundstedt Mar 15 2006, 08:09 AM

Nah, that is not so intresting..

Posted by: helvick Mar 15 2006, 08:20 AM

Well - if you take your idea and create a specular map and a texture map with a less saturated blue you would have quite a convincing effect on something like Celestia. It would be quite a challenge (I think) to animate but you could have a selection of alternate textures.
like Don Edwards is doing http://www.shatters.net/forum/viewtopic.php?p=68207&sid=ecd49b10934d68f09fe3b2a27806b8d2

Posted by: Richard Trigaux Mar 15 2006, 08:27 AM

Interesting work!

But to be noted that, Mars having several well separated basins, the water level would not necessarily be the same everywhere, at least with few water. Fot instance it is likely that the northern bassin had water, at least temporarily, at a time where Helas basin (the deepest) had not.

Posted by: Magnus Lundstedt Mar 15 2006, 09:49 AM

Ah intresting. Do we know for sure that helas basin did not have any water in it, and that the northern basin had, or was that just an example? But that is certainly possible, since it did necessarily not rain over helas basin (like deserts on earth). I guess it is also possible it did not rain anywhere on mars in any significant amounts, etc..

While the best explanation for mars is probably that of an forever dry-planet, I wonder if this scenario would be reasonable;

Mars starts out with significant amounts of water ice, maybe in melted form due to much vulcanism in "embryonic-mars", or that it quickly turns to ice form - "a snowball mars". Then this water-ice boils away due to the low airpressure on mars (water sublimation). After some time the huge amounts of water vapor in the atmosphere increases airpressure significantly; thus allowing for oceans to stay liquid more stable for a longer time. Water vapor is also a powerful greenhouse gas afaik, so the weak sunshine from the young sun is enough to keep temperatures above 0 C. At this time some kind of equilibrium forms between the pressure in the air from water vapor and evaporation of the oceans. The water vapor in the atmosphere is also constantly outgassed in space because of mars low gravity + no magnetic field + solar winds, etc. ?

To compare the order of magnitudes between oceans and atmosphere on earth:

Mass of ocean: 1.4 × 10^21 kg
Mass of atmosphere: 5.1480 x 10^18 kg

(numbers from wikipedia)

So it would probably not be unthinkable that massive amounts of water (maybe in ice-form) on mars could generate a massive H20-rich atmosphere to allow for liquid oceans?

EDIT: I attatch an image of the phase diagram of water, with range now and a example range for what I talked about above:

Posted by: Richard Trigaux Mar 15 2006, 11:56 AM

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

For instance, if you look at http://www.google.com/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).

Posted by: Magnus Lundstedt Mar 15 2006, 01:49 PM

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.

Posted by: David Mar 15 2006, 01:58 PM

You can play a similar game over at Viktor Toth's http://www.vttoth.com/probes/mola.html website. He has the same sort of game for Venus, which is in its way even more interesting (if only for demonstrating how bizarre and unearthlike Venus' topography is).

Posted by: Magnus Lundstedt Mar 15 2006, 02:25 PM

Nice! Albeit too low resolution to be really intresting

Would be nice with highresolution topography data on venus to do the same. Howevera afaiu the surface of venus has "recently" been resurfaced; thus any tracks of ancient lakes, oceans, rivers, etc is probably long gone.

Posted by: Richard Trigaux Mar 15 2006, 03:29 PM

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.






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).

Posted by: Magnus Lundstedt Mar 15 2006, 04:23 PM

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?

Posted by: RNeuhaus Mar 17 2006, 12:55 AM

About the geological marks originated by a "giant surge". I am not sure about your interpretation since the width of channel is not related to the magnitud of flow surge but also it is related to the time of flow. The other factor might play is the mass density. The denser is the water such as a mud along with stones, erodes the land faster than only water. The case is the very often in the andean zone in the rain time which makes big downpour which drags the land very fast and makes channels to be wider. Are you referring width of the channels from Kaiser or Marines Vallies or other where else.

The other factor about the width erosion land is of its composition. Some loose land such as sand, the water can erode it very easy and fast against on a rock and compact surface. The northern land looks less rocky and mostly of silica sand lands.

Back here about to prove about the "big surge" might be resolved after an laboratory empirical observation on different types of land and measure with liquid force (water or other liquid state such as hydrogen, methane or other which becomes liquid at lower temperature that has happened at billions years when the sun was young with less heat radiation).

Rodolfo

Posted by: Richard Trigaux Mar 17 2006, 07:57 AM

Thanks for your contribution. Yes, certain factors like mud, or sandy terrain, could make appear flow marks wider. but I still maintain that such water surges (linking the Nort east part of Tharsis dome, and Vales Marineris, to the northern low lands), were formed by something much more powerfull than our usual rivers. If you look at the Google Mars, these traces are very visible, while M'aadim Vallis (the one which flows into Gusev) is barely visible. However M'aadim vallis is already huge to our standards. At the same scale even our largest rivers would not be visible.

Also the images clearly show a one-time short event. A smaller flow working for a long time can form a large valley, but this valley shows meanders and a narrow bed (Like in France the lower Seine valley), not sand banks the width of the valley. Try to go on a beach, and manage to make some water flow in the sand: if forms water beds which look exactly like the martian formations, but at a much lesser scale. And you notice that these formations are the width of the actual water flow, and that they appear in some seconds, compared to hours with a lesser flow to obtain the same width.


So I still maintain that these formations were created by huge water surges, maybe muddy, or boiling with carbon dioxyd, but not by a continuous small river. This is the mystery.

Posted by: RNeuhaus Mar 17 2006, 09:03 AM

Thanks Richard for your reply:

That part has convinced me. The surge does not make meander rivers. That is a good hit. About the narrow bed at the bottom of the river, it is relative, since it might depends upon to the surface varying resistance to the erosion. About the sand bank, I agree about this, the sand bank is mostly correlated with the amount of flow water. The good examples are the comparision between the Amazon and Nilo deltas.

Rodolfo

Posted by: Bob Shaw Mar 17 2006, 09:03 AM

Richard:

The 'scabland' erosion was, indeed, dramatic, and may well have been more-or-less one-off; but there *are* images showing clear evidence of repeated flows with classic river erosion structures, too. Granted, these are on a more 'normal' scale!

Bob Shaw

Posted by: tty Mar 17 2006, 01:57 PM

The actual surface of seas on Mars wouldn't be "flat" though. Here on Earth the sea surface varies almost 200 meters with respect to an ellipsoid (see: http://kiska.giseis.alaska.edu/input/west/introgeophys/05_sea_surface_and_geoid/)

On Mars the geoid (areoid) is even more irregular (ca 1000 meter), particularly around the the Tharsis bulge and the Hellas basin. To get a true map of shorelines you should drape the "water" over the areoid rather than the topography and then superimpose the result on a topographic map. Areoid maps are avalable from the PDS.

tty

Posted by: ljk4-1 Mar 17 2006, 04:31 PM

The Wikipedia section on Terraforming:

http://en.wikipedia.org/wiki/Terraforming

Has two artworks of Mars if it had oceans:

http://en.wikipedia.org/wiki/Image:Mars_Terra.jpg

http://en.wikipedia.org/wiki/Image:Terraformed_mars_3_stage.jpg