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Subscribe to RSSMars Reconnaissance Orbiter captures the springtime thaw of seasonal carbon dioxide ice on Mars.
The seasonal thawing of carbon dioxide ice near Mars' north pole carves grooves in the region's sand dunes, three new studies reveal.
The discovery, made using observations from NASA's Mars Reconnaissance Orbiter spacecraft, or MRO, reinforces that the Red Planet's surface continues to be transformed today, even though Mars' volcanoes have died out and its liquid surface water apparently dried up long ago.
"It's an amazingly dynamic process," Candice Hansen of the Planetary Science Institute in Tucson, Ariz., lead author of one of the studies, said in a statement. "We had this old paradigm that all the action on Mars was billions of years ago. Thanks to the ability to monitor changes with the Mars Reconnaissance Orbiter, one of the new paradigms is that Mars has many active processes today."
MRO photographed dunes in Mars' far northern latitudes using its High Resolution Imaging Science Experiment camera, or HiRISE. The images revealed a number of grooves appearing in the dunes as the northern spring took hold and progressed. [Dry Ice 'Smoke' Moves Mars Sand (Video)]
The phenomenon is driven by the springtime thawing of a surface layer of frozen carbon dioxide, also known as dry ice.
This thawing occurs first on the ice layer's underside, which is in contact with the warming ground, researchers said. The dry ice sublimes from a solid state to a gaseous one, and pressure builds as more and more gas is produced and trapped.
Eventually, cracks form in the ice, and some of the carbon dioxide gas breaks free, forming temporary grooves in the dune as it hisses out.
The escaping gas also carries sand, which forms dark streaks as it spills across the dry ice covering the dune. These dark fans disappear as the seasonal ice evaporates, and Martian winds erase most of the newly formed grooves before the next winter and springtime roll around.
The grooves are smaller versions of the "gullies" MRO has spotted on other, steeper Martian dunes, which were apparently formed in a similar way, researchers said. And similar processes have been observed near the Red Planet's south pole.
"It is a challenge to catch when and how those changes happen, they are so fast," Ganna Portyankina of the University of Bern in Switzerland, lead author of another one of the studies, said in a statement. "That's why only now we start to see the bigger picture that both hemispheres actually tell us similar stories."
The three new studies, which appear in the journal Icarus, were based on observations made by MRO over three Martian years, or about six Earth years. The papers document a variety of seasonal changes on Mars, including the dune grooves and the distribution of water frost, which is blown around by springtime winds.
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What about the fact that they found seasonally melting water ice on the poles? That doesn't warrant a story or investigation by a rover? We only want to look at the parts of the planet we know have been dead for millions of years? Really? I mean, this isn't conspiracy theory it's been found by the Mars Reconnaissance Orbiter.
Here's some video and another story on it:
http://www.youtube.com/watch?v=zV4fws-VaIc
http://www.livescience.com/24265-mars-water-streaks-seasonal-flows.html
If you poke around youtube and google you'll find more.
Good point.
I do not buy the description that the much darker areas are "dark sand". If that was the case, and this was happening on a seasonal basis, over and over again, the color of the dunes would be equivalent to the other shell of them after the ice receded.
There appears to be conflicting opinions within NASA.
There is ample evidence of water on Mars in the past, lots of it. And most like there is still a lot of it a bit under the surface as ice. There is probably some seasonal melting that occurs along the flanks of these slopes when summer comes at those latitudes. So these areas away from the poles are not dead, but indeed show evidence of water flow. That doesn't seem as likely at the poles where it doesn't get warm enough for water ice to melt and CO2 freezes...at -109 F.
I had previously mentioned co 2 was quite possibly a player in what we see on mars but as I read this article, it becomes apparent that co 2 phase transition may also account for SOME (not all or even most) of the features we see on earth. Now that I type this I realize that not only may it be a factor from earths way early history, but, I suspect that if we look carefully enough, we may very well find a small effect delineated over time occurring on earth right now!! I have no immediate suggestions on where to look, but perhaps this is yet another good thesis paper theme for a clever science student. Just don't get carried away with making it some sort of climate altering grand scheme, it is not, whatever the process is, I am more than certain it has been in play longer than man has. As for mars, I have an idea that several like process have been in play and mimic h2o's effects, just over a longer time span. Not to suggest mars never had liquid aggregations (pools,ponds,lakes oceans etc.) but that we should not be too quick to proclaim any theory as absolute nor impossible. Rather judge them all with prudence, skepticism and a realization that we are, so far, just a blip in time relative to everything else. Great ongoing work JPL, and nice article nbcnews. More robotic missions are called for. An impetuous to streamline such missions and find methods to reduce the overall assosciated costs are also in order. For instance, what is anyones guess as to the maximum total number of robot missions we could maintain (not talking dollars but raw ability) in parallel? I'll say about 21.
(just for the record, I still believe mars has hugh underground oceans beneath it's crust that we have yet to verify...at the same time I bet the earth also has large underground water deposits that we, as of today, have no awareness of.)
It is nice to know that we can potentially harvest (or surface mine) this seasonal frozen CO2 for propulsion and other purposes in sizable volume or mass at the Martian poles. (The same also goes year around for frozen H2O as well, BTW.) - RC
(Please also note that generally speaking you will not deplete the planetary supply of these resources, because most of it will end up back on the surface of Mars. (I personally think there are vast oceans of H20 underground on Mars.)) - RC
(The Martian soil itself is a very dense atmosphere, and this dense atmosphere has captured or trapped a lot of water over the billions of years, which in turn has the tendency to descend to the bedrock as a Martian water table.) - RC
(The ultra fine Martian dust especially ensures this, BTW) - RC
(And as I pointed out before, water makes a very good construction cement at the proper temperatures. All you need is the congregate and the forms (and the requisite insulation to enjoy it all)!) - RC
Hm.... almost like you've been there... any relationship to John Carter? :P
(Sorry, I really meant "aggregate", at least in light of the latest 'refinements' in definition regarding composites.) - RC
(MSpielman, why don't you ask him if he is any relationship to me? (:-)) )
Head north Rover Curiosity .
Check out and analyze some samples from around those freezing sand dunes .
Drilling there should be allot easier also .