Evidence For Liquid Water On a Frozen Early Mars

Matt_dk writes "NASA scientists modeled freezing conditions on Mars to test whether liquid water could have been present to form the surface features of the Martian landscape. Evidence suggests flowing water formed the rivers and gullies on the Mars surface, even though surface temperatures were below freezing. Dissolved minerals in liquid water may be the reason."

Re:Whatever happened to...

[Yvanhoe]

Still valid, but this is not the question. They are trying to determine wether big bodies of water existed on Mars. About Mars having huge quantities of water ice, we know it from several years, we even have pictures [esa.int] of it and even a map [blogspot.com] of Mars' aquifers.

Re:Whatever happened to...

[b0ttle]

Researchers did an experiment simulating the temperature and pressure conditions on Mars, and found that liquid water is possible because of the perchlorates Phoenix found on the soil.
http://www.universetoday.com/2009/05/26/more-researchers-say-liquid-water-present-on-mars-now/ [universetoday.com]

Re:Whatever happened to...

[TapeCutter]

It's been suggested recently that the perchlorates invalidated the micro-oven experiments, Apparently when heated they release large amounts of oxygen that would incerate any organics. Since I only have a vauge idea of what a perchlorate is, I have no idea if that's a valid criticisim. But given the possibility of ground water I think the methane hots spots [google.com.au] are worth a closer look.

Re:Warmer?

[TapeCutter]

"Weather or not its breathable"

Somewhat ironically, life is what made our atmosphere breathable. Without life it's highly unlikely there would be anything more than trace amounts of free oxygen in an alien atmosphere.

Re:Warmer?

[scorp1us]

That's a very good question. But the problem is one of sublimation. That is from solid state to gas. It happens in cold dry air. Snowcap-free Mt Kilimanjaro in Al Gore's "Incon. Truth" didn't melt from global warming. It sublimated because farming on the windward side made the air passing over the mountain drier.

The only way to keep the liquid water around is to have a denser, wetter atmosphere.

The problem with storms filling in gullies is that the dust particles are very fine, and have to be since there's not a lot of gas to move them. Without moisture, it is hard to bond to other particles (static charge being the leading cause) so its hard to have some drift that won't be blown away at the next dust storm.

That being said, there is evidence of water percolating. This won't be able to make large new gullies, but it will help maintain the ones that are there. And in fact, we have no idea of the gullies that exist that are filled in by dust. I can only conclude that the gullies we see are stable features left over from a time long ago. The "last of the line" so to say.

Re:Warmer?

[Geoffrey.landis]

...we also know that there are massive periodic dust storms. Don't you think the storms would have eroded away the water gullies, or at least filled them with dust by now ? So I would say the formations are a lot more recent than "in the ancient past when Mars had a bigger atmosphere".

The cross-section weighted average particle size of the dust particles is about 5 microns. Think of the particles as being ten times finer than the particles that make up talcum powder. It's more like cigarette smoke than it's like sand; it's not very abrasive, and doesn't do much in the way of erosion.

Sandstorms, like we have on Earth, do much more erosion.

However, yes, burial and deflation of features is a well-known effect on Mars. In some places the ancient surface is exposed, but in other places it is well buried. There are a lot of places on Mars where all you can see is the overlayer of dusty soil.