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Martian Canyons May Have Been Carved By Wind
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.
While here on Earth with a good 1 atmosphere of pressure, wind might be 10 times faster than water. Now how does that scale to Mars' 0.6% atmospheric pressure?
Seven puppies were harmed during the making of this post.
It's pretty obvious that Mars was primarily carved by arc discharge.
- In Soviet Korea, only old people loose all their bases to Natalie Portman's petrified hot grits overlords.
If you're going to dumb it down that much, why not just call it 'something'.
It certainly sounds like "something" is exactly the level of confidence in the information at this point!
Is it just my observation, or are there way too many stupid people in the world?
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.
Is it just my observation, or are there way too many stupid people in the world?
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.
systemd is Roko's Basilisk.
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?
Wind, water, lava flows.... Another on first consideration implausible one is electric discharge. But some pretty good points can be made about these matching the observations. I have never heard the proponents of that model provide a convincing and comprehensive explanation of what gets and keeps the discharge going, though.
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?
Where are we going and why are we in a handbasket?
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...i get it...
but it's all "fluid"...right?
Thank you Dave Raggett
I'm not saying it's aliens, but it's aliens.
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 released. This process would release a lot of smaller rock and dust, that sometimes looks like material washed down by moving water.
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 have done a significant amount of the erosion work. Thus, it is more like the question of being hit by a 20 MPH wall of water once or a 2 MPH breeze (with occasional strong gusts) for several millennia. If I was a rock, I might prefer the water.
And if I remember correctly, Martian wind often is in the form of sandstorms. So this would be fast moving with an abrasive in the fluid to do the mechanical scouring work.
Although I wouldn't simply assume wind-based erosion to be the case on Mars, I don't understand how it seems so implausible.
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.
Somehow the first time I read this it came out Martion crayons not canyons. Confused the hell out of me.
Looking at http://en.wikipedia.org/wiki/Compressible_flow
"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 occurs."
So: in physics fluids can be gases or liquids, and the post you're correcting was in fact right on that.
But from that Wikipedia quote whether a gas and a liquid "follow essentially the same physics" would seem to depend on the Mach number of the gas being relatively small?
"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*, bringing material down to the water flow, where it can we washed away, or carrying it away as fine dust. The question is how much of each?