Earthlike Mars? Options

[marsbug]

An small impact could do a good job of mixing dark rock and dust with ice....ok like I said it's my pet idea this month!

But, with regards to the presence of a frozen northern ocean, wouldn't a census of small craters churning up ice be a nice cheap way to map ice distrubutions at depths greater than a meter? I assume that's beyond the limits of current techniques or the ice turned up at these craters wouldn't have been a surprise! A job for someone with patience who doesn't mind combing HIRISE images of mars I think, with some follow up by CRISM to confirm that it is ice not just light toned soil .

[dburt]

Interesting thought. In fact, I'd be surprised if someone hasn't already submitted a proposal to NASA to do something very similar (not that I've seen one yet). If not, someone (not me!) may well do so now that you've posted that excellent idea. (Sometimes you just gotta love academia...)

-- HDP Don

[marsbug]

A press release from Prof Vincent Chevrier (who's been known to hang out on BAUTforum and answer questions on the Phoenix mission), whose university of Arkansas group do a lot of work simulating conditions on mars.

[serpens]

Thanks for posting the link Marsbug, it has all been very quiet on the Phoenix results analysis front. But there is a gap between between 'potential' to exist and 'do' exist. The article doesn't make clear whether the Mg perchlorate brine was introduced to the experiment, or if it formed naturally from ice deposits in the in the simulated martian environment of pressure / temperature / atmospheric composition and regolith. As Vincent has rightly pointed out elsewhere, the contentious 'droplets' on the lander legs do not prove the existence of brines on Mars, but are (whatever they may be) the result of the alien environment created by the landing and operation of Phoenix. Introduction of a formed brine to an experiment has the same caveat and the use of 'potential' in the article could reflect Vincent's normal and laudable, conservative approach. The TECP results did not provide any evidence of the development of films or brines. That doesn't mean they are not there - but it does reduce the likelihood.

[marsbug]

I suspect it was introduced to the chambre to, but I'll ask. For anyone following this topic we're talking with Prof Chevrier here.

The evidence doesn't point to the phoenix site being rich in brine, but if a brine formed from components present at the phoenix site can be stable under accurately reproduced conditions then, given the size of the martian arctic, I'd bet my favourite coat (and it's a very nice coat, if a bit matrix-esque for every day use) that brines do occur, even if only rarely.

There is another thread, here, where we were taking over the formation of brines with Hanna Sizemore, a phoenix team postdoc. She is adamant that even under ideal conditions the most liquid water you'd see at the phoenix site is a few monolayers. However she was fending off talk of liquid droplets on the landers legs, and even open pools of brine, so she might be willing to go as far as 'ten monolayers, in the right spot under the best conditions imaginable' or similar if she doesnt feel like the only skeptic in the room. I hope there's room in the martian arctic for a few exceptional microclimates where brine can form in detectable amounts, becuse I reeally like that coat!

It seems that stable brines can exist on mars, using solutes available at the phoenix landing site, and at the MER's sites and the viking 1 site (see link on post 40), and there are reserves of water ice at lattitudes as low as 45 degrees north (see link on post 44), so I'll eat the coat if there aren't a few damp patches up there from time to time. It's leather so I'll have to get a big tenderiser

[glennwsmith]

And here's something hot off the press from the Imperial College of London which supports the possibility -- no, let's say probability -- of a frozen Oceanus Borealis. The link is as follows:

http://www3.imperial.ac.uk/newsandeventspg...-10-59-30#fni-2

Their thesis is that the Late Heavy Bombardment added huge quantities of water to the surfaces of both Earth and Mars. I quote briefly:

"They found that on average, each meteorite was capable of releasing up to 12 percent of its mass as water vapour and 6 percent of its mass as carbon dioxide when entering an atmosphere . . .Using published models of meteoritic impact rates during the LHB, the researchers calculated that 10 billion tonnes of carbon dioxide and 10 billion tonnes of water vapour could have been delivered to the atmospheres of Earth and Mars each year . . . However, researchers say Mars’ good fortune did not last. Unlike Earth, Mars doesn’t have a magnetic field to act as a protective shield from the Sun’s solar wind. As a consequence, Mars was stripped of most of its atmosphere. A reduction in volcanic activity also cooled the planet. This caused its liquid oceans to retreat to the poles where they became ice."

[serpens]

As Glenwsmith indicated on another thread, Oceanus Borealis is linked to the Meridiana lake/playa hypothesis. Taking another look at some of the features in the north it almost seems time to dust off some of Nick Hoffman 's White Mars observations, but with a view to reconsidering some of these northern outflow features as submarine water flow turbidites rather than Nick's proposed cyroclastic (CO2) cause.

[glennwsmith]

The possibility that there is a frozen Oceanus Borealis beneath the dust of the northern plains has implications far beyond Mars, of course. If I may be allowed to speak in an enthusiastic vein for a moment, consider that Mars is only the second planet that we have been able to "sample". Finding large quantities of water there would thus, in a sense, double the amount of water likely to be extant among the universe's population of rocky planets.

The verification of an Oceanus Borealis also increases the liklihood that we will find significant quantites of water on our own moon; or -- to put this in negative terms -- if Mars is cold and dry, this does not bode well for the success of the current LCROSS mission to the moon.

By the way, I'm sure most of you are aware of yet another recent paper pointing to the presence, at least in the past, of a significant body of water on Mars; the link follows:

http://www.colorado.edu/news/r/7e9c22ec0cd...4ed2e29f16.html

[serpens]

http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1939.pdf

One of a number of papers dealing with Mars Aqueous Processes on day 3 of the 40th Lunar and Planetary Science Conference 2009 held in March. Just a touch of home town enthusiasm in the CU media release page.

[tim53]

By the way, I'm sure most of you are aware of yet another recent paper pointing to the presence, at least in the past, of a significant body of water on Mars; the link follows:

http://www.colorado.edu/news/r/7e9c22ec0cd...4ed2e29f16.html

I looked at this paper after I was notified of the press release last week. Their "shoreline" is a fault scarp in alluvium, similar to this example from Nevada. I worked there 30 years ago. It can be difficult to distinguish shorelines from fault scarps across the alluvial fans in the Great Basin because they often are directly associated with one another. This example is "easy" because there's a graben in front of the main fault, but there isn't always one. In this valley ("Dry Valley" I think it was called, though the map software doesn't show the name) west of Caliente, Nevada, the paleolake was rather small and didn't rise to the elevation of the fault scarp.

Fortunately, of course, we could drive up to and walk on the feature to help us determine what it was.

In the martian example, we can't do that (not for a while, at least). So I'm afraid that in my view at least, the paper fails to provide the extraordinary proof that the claim "This is the first unambiguous evidence of shorelines on the surface of Mars" represents. ...in addition to it simply being an untrue statement.

-Tim

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[mhoward]

Yeah, I'm no expert on these things, but I cringed at the word "definitive." I also notice that the Wikipedia entry for Shalbatana Vallis has been updated with this info, including the word "definitive," which I think might be a little premature.

[tim53]

I hate the word "definitive." All it takes is a reasonable doubt to make one look silly for using it.

As a result, probably a lot of people think I'm less sure of myself than I think I am!

-Tim.

[SteveM]

Agree that "definitive" is out of place in most articles, and particularly in this one. I'd just ease off the criticism a bit since this is from UC Boulder's press office, not from the researchers.

[tim53]

Agree that "definitive" is out of place in most articles, and particularly in this one. I'd just ease off the criticism a bit since this is from UC Boulder's press office, not from the researchers.

Well, they may not have used that specific word, but the title of the paper is "Positive Identification of Lake Strandlines in Shalbatana Vallis, Mars" and the abstract says "first direct evidence of strandlines" and the conclusions say "first direct evidence of unambiguous strandlines," which is about as strong a statement as one can make.

Even if the specific feature had merit (it doesn't, unless one is interested in local structural geology), the degree of certainty expressed in the paper is unwarranted.

-Tim.

[glennwsmith]

Serpens, thanks for the link to the actual Shalbatana Vallis paper -- it's darned interesting; and tim53, thanks for making me want to take a closer look. The point is made in the conclusion that billions of years of aeolian activity (journalese for wind!) have eroded most former deltas and shorelines, but these in the Shalbatana Vallis have managed to survive to some greater or lesser extent -- making this area a possible candidate for future (Mars Sciene Laboratory aka "Curiosity"?) landings.

Also, is anyone out there good enough with the Hirise dataset to be able to post a non-3D, maximum resolution image of the area represented by Fig. 3A in the paper? (This shows the putative shorelines.) I would be forever in your debt.