Could low altitudes on Mars support liquid water?

[Findthepin1]

I recently came across a Mars Express photograph of Valles Marineris filled with fog. Given the canyon's relatively high air pressure, equatorial temperature, and apparent possibility for humidity, is it possible that it can contain transient puddles of water under the right conditions?

Edited June 19, 2015 by Findthepin1
oops

[Kryten]

No, the pressure still isn't high enough to reach the triple point; the 'fog' was most likely dust. You could theoretically have puddles at the bottom of Hellas Planitia, which is quite a bit deeper, but would still require rare temperature conditions and high salinity.

[Exoscientist]

Actually Valles Marineris quite frequently exceeds the pressure triple point of 6.1 mbars. For instance even at the Viking landing sites this was frequently exceeded. The problem is the pressure is still so low that when the temperature rises just a little above freezing the water will boil away. So it would be just a tiny window of temperature where the water could be liquid before either freezing or evaporating.

However, the presence of salts could extend this temperature range.

Do you have the link to the images ?

Bob Clark

[Findthepin1]

In this part of the canyon the elevation is about 4600 meters below the datum (according to Google Earth), and I tried to calculate the air pressure at that altitude, which gave me just under 0.91 kpa. Wolfram|Alpha says the boiling temperature of water at this temperature is about 5.445 degrees Celsius. If the water is salty, the melting temperature will be lower, but I'm not sure if this will affect the boiling temperature measurably. Wikipedia (itself sourced from cab.inta-csic.es), says the average high temperature in the warmest month in equatorial Mars is 4 degrees Celsius, which is below the boiling temperature by a relatively large margin (~27% of whole temperature range below boiling temperature).

As for the mentioning of the possibility of puddles in Hellas Planitia, the boiling temperature at the lowest altitude (which I usually just refer to as Low Point) is between 8.98 and 10.04 degrees Celsius (varies because of seasonal pressure changes). This is sufficient to support regular water without salt or anything (although given what we've found in the regolith, salt ending up in bodies of water is a near certainty) and since Low Point in particular and Hellas in general is further from the equator, the temperature shouldn't commonly approach the boiling temperature.

I would also like to correct an error that I made in the OP. This is a Mars Express image, not HiRise as I mentioned. The post has been updated to account for this.

Edited June 19, 2015 by Findthepin1

[lajoswinkler]

That's not fog. It's a probably a near infrared image, obviously false colored. There are no bluish areas on Mars. It's all false colored infrared.

Conditions on Mars allow for brief occurences of muddy, concentrated brine coming close to surface in the lowest parts of the planet surface, burping a bit and evaporating, leaving a salt-mud residue. That's all.

[Kryten]

That's not fog. It's a probably a near infrared image, obviously false colored. There are no bluish areas on Mars. It's all false colored infrared.

This is pretty much gibberish. Please go and try and actually learn something about colour imaging before coming up with more of this stuff, there'd be no point even applying 'false colors' to a solely IR image.

As for the image, after looking into it a bit more it seems to be transient ice crystals, similar to cirrus clouds on earth. No liquid state necessary.

[Kerbart]

I recently came across a Mars Express photograph of Valles Marineris filled with fog. Given the canyon's relatively high air pressure, equatorial temperature, and apparent possibility for humidity, is it possible that it can contain transient puddles of water under the right conditions?

Relative is the keyword here. Given that the surface atmosphere of Mars rivals the vacuums most high school labs can produce I wouldn't get my hopes up too much.

Let's put it this way: when flying (at the regular altitude of 35,000' to 40,000') do you ever fly through clouds? That tells you something about the ability of the atmosphere to contain liquid water at that point. And keep in mind that you'll have to double that altitude to get at the pressure levels where Mars' atmosphere is at.

[DMSP]

This is pretty much gibberish. Please go and try and actually learn something about colour imaging before coming up with more of this stuff, there'd be no point even applying 'false colors' to a solely IR image.

As for the image, after looking into it a bit more it seems to be transient ice crystals, similar to cirrus clouds on earth. No liquid state necessary.

What?

I think Lajoswinkler is correct about the false colors.

[rtxoff]

This is pretty much gibberish. Please go and try and actually learn something about colour imaging before coming up with more of this stuff, there'd be no point even applying 'false colors' to a solely IR image.

As for the image, after looking into it a bit more it seems to be transient ice crystals, similar to cirrus clouds on earth. No liquid state necessary.

This is definitely a false color image.

[lajoswinkler]

Of course I'm right. Any photo of Mars where bluish colors are visible is a false color one. That's why sometimes you see blue, deep green rocks, sometimes blue sky. Using true colors (true color is an arbitrary term obviously, meaning what human eye sees in noted conditions) Mars is rusty, peach reddish desert.

Examples.

False colored and with elevated saturation over some channels.

Edited June 20, 2015 by lajoswinkler

[Kryten]

He says it's near IR. A near IR image would be monochromatic, it's perfectly possible for ice crystals to appear bluish in a standard RGB image, and HRSC has the filters to produce RGB images. Given this image was produced by an amteur for a popular audience, assuming it's false is just the kind of paranoid raving about colour we've all grown to expect from Lajoswinkler.

[lajoswinkler]

I knew I shouldn't had deleted the "full spectrum" part. Not only can near infrared images don't have to have one channel, but also VIS images can be extended with them, so colors obviously shift. In photography jargon that's also sometimes called infrared.

That, plus corrections and boosting the saturation makes the wackyland images of Mars we usually get.

I suppose you think this is what Mars actually looks like. LOL

[rtxoff]

While the HRSC is capable of producing RGB only images it would be a waste of its capabilities. HRSC is always transmitting images with all 9 channels it records. It's up to the mission guys to convert this images in RGB form so we can watch them but they are free to transform channels like near infrared into the red channel for an example so we could also see the infra red stuff in the images. Even if they would compose a image that uses only the 3 RGB channels it would still be a false color image.

If you're being pedantic you can even say that images taken with normal consumer cameras are false color images because a composite image of the channels a CCD chip records never will reach the natural color capabilities of the human eye and also most consumer cams add some effects to the pictures to look more attractive.

[Kryten]

I suppose you think this is what Mars actually looks like. LOL

That's a VMC image... it's from a standard RGB CMOS camera originally tacked on to view the Beagle 2 release. It's by far the closest you're over going to get to what you've been raving about all this time, so of course you think it looks wrong.

Edited June 20, 2015 by Kryten

[lajoswinkler]

LOL I give up.

[NFUN]

I'm tempted to give you guys "a room" in which you might argue the intricacies of photography together, since you are so insistent on doing it in every thread that remotely relates.

Findthepin1, dissolved salts will affect both the boiling and melting point. See colligative properties.

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php

[Dres]

I agree, its a false color image of the dust in the canyon floor. You can tell, mainly because it has actual terrain in it (such as a crater. middle of the canyon on the left).

[KerikBalm]

No, the pressure still isn't high enough to reach the triple point; the 'fog' was most likely dust. You could theoretically have puddles at the bottom of Hellas Planitia, which is quite a bit deeper, but would still require rare temperature conditions and high salinity.

Would it require high salinity?

I thought the pressure there was sufficient to get just above the triple point of water.

Sure... its a very narrow temperature range between freezing and boiling (arbitrarily small as one gets arbitrarily close).

Salinity would help expand the temperature range, but it shouldn't be required, should it? Wouldn't pure water be able to exist in an open container (lets say thermally regulated) at the bottom of Hellas?

Sure, it would eventually evaporate as it does on Earth, but it wouldn't neccessarily boil or freeze.

No?

[Spock1108]

A recent study showed that in the crater Gale, and many other areas of Mars, the salt concentration is such as to maintain liquid water in the first 5 cm of ground! Of course not all day, but especially the morning and evening of Martian winter!

http://www.nature.com/articles/ngeo2412.epdf?referrer_access_token=gS933ikyIyArQcRigENli9RgN0jAjWel9jnR3ZoTv0MJu0lcwUIHOohrHD9R7vfCbisXPqIIdfuDtxZ9mKb0jiNnneDrotyvTjBSeFU0BQ6T3JEjxDnnfl9MUOZfIISPsGZoAYI10Xd2UnwaV5-X1wP9bnNAsBM650HYFIxVc7oSxK9dq7oSBhaPBjYLXOMf&tracking_referrer=www.bbc.com

[Findthepin1]

Would it require high salinity?

I thought the pressure there was sufficient to get just above the triple point of water.

Sure... its a very narrow temperature range between freezing and boiling (arbitrarily small as one gets arbitrarily close).

Salinity would help expand the temperature range, but it shouldn't be required, should it? Wouldn't pure water be able to exist in an open container (lets say thermally regulated) at the bottom of Hellas?

Sure, it would eventually evaporate as it does on Earth, but it wouldn't neccessarily boil or freeze.

No?

The temperature window at Low Point in Hellas is about 9-10 Celsius degrees wide. The air pressure varies seasonally between 1.155 and 1.24 kpa. This is well enough to sustain liquid water.

- - - Updated - - -

A recent study showed that in the crater Gale, and many other areas of Mars, the salt concentration is such as to maintain liquid water in the first 5 cm of ground! Of course not all day, but especially the morning and evening of Martian winter!

http://www.nature.com/articles/ngeo2412.epdf?referrer_access_token=gS933ikyIyArQcRigENli9RgN0jAjWel9jnR3ZoTv0MJu0lcwUIHOohrHD9R7vfCbisXPqIIdfuDtxZ9mKb0jiNnneDrotyvTjBSeFU0BQ6T3JEjxDnnfl9MUOZfIISPsGZoAYI10Xd2UnwaV5-X1wP9bnNAsBM650HYFIxVc7oSxK9dq7oSBhaPBjYLXOMf&tracking_referrer=www.bbc.com

http://www.media.inaf.it/wp-content/uploads/2015/04/Brines_graphics.png

How much water does Gale have?

Edited June 22, 2015 by Findthepin1

[Spock1108]

Few, but just to have similar phenomena, along the slopes of Mount Sharp...

[Windspren]

That's a VMC image... it's from a standard RGB CMOS camera originally tacked on to view the Beagle 2 release. It's by far the closest you're over going to get to what you've been raving about all this time, so of course you think it looks wrong.

Soooo.... Mars has clouds now? What happened, did someone install RSS and mess up the EVE install?

[Exoscientist]

http://astrobob.areavoices.com/files/2013/09/fog_valles_marineris-ESA-Mars-express.jpg

In this part of the canyon the elevation is about 4600 meters below the datum (according to Google Earth), and I tried to calculate the air pressure at that altitude, which gave me just under 0.91 kpa. Wolfram|Alpha says the boiling temperature of water at this temperature is about 5.445 degrees Celsius. If the water is salty, the melting temperature will be lower, but I'm not sure if this will affect the boiling temperature measurably. Wikipedia (itself sourced from cab.inta-csic.es), says the average high temperature in the warmest month in equatorial Mars is 4 degrees Celsius, which is below the boiling temperature by a relatively large margin (~27% of whole temperature range below boiling temperature).

As for the mentioning of the possibility of puddles in Hellas Planitia, the boiling temperature at the lowest altitude (which I usually just refer to as Low Point) is between 8.98 and 10.04 degrees Celsius (varies because of seasonal pressure changes). This is sufficient to support regular water without salt or anything (although given what we've found in the regolith, salt ending up in bodies of water is a near certainty) and since Low Point in particular and Hellas in general is further from the equator, the temperature shouldn't commonly approach the boiling temperature.

I would also like to correct an error that I made in the OP. This is a Mars Express image, not HiRise as I mentioned. The post has been updated to account for this.

Thanks for the image and the calculations. Note also measurements by Mars Curiosity suggest that thin films of liquid water might exist temporarily near the surface on Mars:

Evidence of liquid water found on Mars

By Paul Rincon

Science editor, BBC News website

http://www.bbc.com/news/science-environment-32287609

Bob Clark

- - - Updated - - -

This is pretty much gibberish. Please go and try and actually learn something about colour imaging before coming up with more of this stuff, there'd be no point even applying 'false colors' to a solely IR image.

As for the image, after looking into it a bit more it seems to be transient ice crystals, similar to cirrus clouds on earth. No liquid state necessary.

Correct. Clouds don't have to have liquid water. Clouds on Mars consisting of ice crystals have been known on Mars since the earliest telescopic observations of the planet. But these images are known by the infrared signatures to be clouds not dust.

Here's another famous image from the Viking missions:

Clouds in Noctis Labyrinthis.

This image shows early morning fog in the Noctis Labyrinthis, at the westernmost end of Valles Marineris. This fog, which is probably composed of water ice, is confined primarily to the low-lying troughs, but occasionally extends over the adjacent plateau. The region shown is about 300 kilometers (186 miles) across.

http://www.solarviews.com/cap/mars/noctis.htm

Bob Clark

[cantab]

The lowest altitudes on Mars such as Hellas do have pressure higher than the triple point of water. But for liquid water to be stable depends on the partial pressure. Unless the air was 50% water vapour, which seems very unlikely, the water would evaporate.