Martian Canyons May Have Been Carved By Wind 39
sciencehabit writes Ancient canyons scar the surface of Mars, a relic from a time billions of years ago when rivers flowed on its surface. But water may not be the only factor that shaped these canyons—the wind whipping through them could be just as important, according to a new study of river canyons on Earth. Scientists studying chasms in the Andes mountains in northeast Chile have found that wind carves some canyons 10 times faster than water. The discovery may be significant for understanding how much water flowed on the surface of ancient Mars.
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"May" isn't the word you think it is.
To understand science, one has to understand that 'may' is in fact a central concept; it is the possibility that something may be true, that guides our research. In most cases, when scientists use the word 'may', it is because they think there is a very good possibility that this is true. In the case of wind erosion and canyons, I would say it is just a question of figuring out how much each factor - wind and water - contributed. Intuitively, water mostly erodes *down*, whereas wind erodes *sideways*, bring
Umm (Score:2)
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It probably compares pretty well when you consider the speed at which water flows on mars... :-P
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The flip side is that gravity is about 1/3 Earth's there. That means it's easier for thin winds to move particles.
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Earth doesn't have the huge global dust storms that Mars gets. But at any rate, 4 billion years ago Mars had a much thicker atmosphere.
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If you're going to dumb it down that much, why not just call it 'something'.
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Which would you rather be hit with, a 20 MPH wind, or a 20MPH wall of water? Remind me again how they are the same.
If you are trying to figure out what formed some canyons, the WHAT and not just HOW is pretty important. If you are just going to call it 'flow' why bother looking at it at all?
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Which would you rather be hit with, a 20 MPH wind, or a 20MPH wall of water? Remind me again how they are the same.
If you are trying to figure out what formed some canyons, the WHAT and not just HOW is pretty important. If you are just going to call it 'flow' why bother looking at it at all?
Water and wind both are fluids. They have very different properties, but follow essentially the same physics. That is how they are the same.
The analogy with being hit once by a wave of the same speed is not apt. Although it appears clear now that water existed on Mars, the abundance of this still is being investigated as is the history and geographic distribution. It is possible that water flowed only sporadically in many areas of Mars. If that is the case, then a slower but more persistent wind could hav
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I understand all that, and I am not saying that wind erosion is implausible. What I don't understand is the desire to remove the substance doing the erosion, wind or water, from the discussion and just reduce it to 'a flow'. It seems to me that wind or water actually matters.
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Looking at http://en.wikipedia.org/wiki/Compressible_flow [wikipedia.org]
"Compressible flow (gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. Gases, but not liquids, display such behavior. To distinguish between compressible and incompressible flow in gases, the Mach number (the ratio of the speed of the flow to the speed of sound) must be greater than about 0.3 (since there is a density change that is greater than 5%) before significant compressibility occ
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It certainly sounds like "something" is exactly the level of confidence in the information at this point!
Electricity. (Score:3)
That's preposterous (Score:2)
I'm pretty sure naturally occurring lasing is still on the table, and I find that highly likely compared to several of the options such as arc discharge, giant space worms, and a young, eccentric billionaire who traveled there to engage in some planetary bondage play, the scars of which haven't yet healed.
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Carved by wind? (Score:2)
Carved by wind? What does that even mean?
Ohhh, wind. Hard to tell the difference when it's written down.
It also ruins any attempt at making a joke about it. See above.
So many physically implausible explanations... (Score:2)
Just how warm was Mars surface back then (Score:2)
that water could flow on it?
And what accounts for the difference in surface temperature, given that Mars's orbit didn't shift by that much?
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that water could flow on it?
And what accounts for the difference in surface temperature, given that Mars's orbit didn't shift by that much?
Loss of most of its former atmosphere.
fluid (Score:2)
ianap but fluid dynamics is actually really interesting and relevant
everything behaves according to fluid dynamics principles...well...that's reductive but it's true for so many things including planets, light waves and typewriters
was it wind or water?
was it liquid water or water vapor?
see how the distinctions start to change?
this is about the recent "Mars had a huge ocean" news story...it was an easy pick for news editors, it's fun and has a cool graphic of an artists's conception of Mars with a huge ocean
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Yes, the situation is fluid.
Let's all say it together (Score:2)
I'm not saying it's aliens, but it's aliens.
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Aliens with fans
Ice-dust strata weathering (Score:2)
While it won't account for all canyons, I suspect there could be Mars-specific mechanisms, such as layers of dust/ice/dry ice that build up over the ages and metamorph under pressure into stratified rock. Then something like a meteor strike disrupts the surface, exposing the strata at an edge, allowing the ice to sublimate, weakening the rock structure and allowing accelerated crumbling of the rockface, exposing more icy strata to the same forces of decay - including wind that blows away some of the dust r
Martian crayons? (Score:2)
Somehow the first time I read this it came out Martion crayons not canyons. Confused the hell out of me.
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