Frosty blue dunes on Mars
It’s been a while since I’ve posted a jaw-dropping high-res picture from Mars, so how about this one: a gorgeous shot of frost coating dunes on the surface of the Red Planet?
[Oh yes, you want to click that to enaresenate.]
This picture was taken by the HiRISE camera on board the Mars Reconnaissance Orbiter, which takes extremely detailed images of the surface of the planet. It shows wind-driven sand dunes on Mars, rippling in a similar way as on Earth. The sunlight is coming from the upper left direction, and where the light hits the surface you can see the familiar reddish cast; that’s actually from very fine-grain dust laden with iron oxide — rust!
But the shadows, where the Sun doesn’t reach, it’s cold enough that carbon dioxide in the Martian air freezes out, forming a thin layer of dry ice on the surface. In this image — where the colors have been enhanced so you can see the effects better — this shades the dunes blue. You can see the frost not just covering the dunes in general, but hiding in the troughs of the ripples too (which I think is why the sunward facing parts of the dunes can look blue; that’s from the ripple shadows). The non-color-enhanced version showing the entire dune region can be found here — and is stunning in its own right.
These dunes fascinate me. The sand on Mars is actually basaltic, making it look grey to the eye. Those grains are big enough that they don’t move as easily as the finer dust, and they pile up to form the big dunes, with the redder dust coating them. The color can change when frost forms, as in the picture above, but you also get incredibly dramatic and simply stunning patterns when dust devils — tornado-like vortices that form when wind blows over warm air rising off the surface — lift up the red dust and expose the grey basalt underneath. The swirling patterns are intricate and incredible, as you can see in this picture here (click to embiggen and get more details).
Pictures like this remind me viscerally that these objects we see in the sky are not just some distant lights, they are whole worlds. They have fantastic details and are as diverse and have complex interactive systems as any we find on Earth. This makes their study important, fascinating… and of course, astonishingly beautiful.
Image credit: NASA/JPL/University of Arizona. Tip o’ the heat shield to HiRISE on Twitter.
Related posts:
- The artwork of the Martian landscape
- Martian dunes under the microscope
- The Devil is in the details
- Happy first day of spring… Mars!
Comments (27)
Links to this Post
- Deserts on Mars and an old TRC essay. « The Relative Comment | February 27, 2012
- currently… | flying buttresses | February 28, 2012
- Linkification » L’esprit d’escalier | March 2, 2012
- Frosty blue dunes on Mars « Xenophilia (True Strange Stuff) | March 2, 2012
10 on the scale of awesomeness
That second one looks like it would make a good tattoo.
Enaresenate?
What has this to do with compounds of arsenic?
(Yes, I know that it’s spelt arsenate not aresenate, but that was too good a straight line to let go.)
What a fine desktop background image!
Both of those pictures are life-altering. My head literally swims from looking at the full page images and “Across the Universe” plays inside. Thanks so much for your site.
Those aren’t dust devil tracks in the second picture, they’re crop circles.
Nigel Depledge, I was thinking encyanate.
Interesting and awesome as always!
Wow… is that a sort of interference pattern to be seen on the center dune? Phil, this is so beautiful. Thank you for all you do.
With all that sand likely building up static, any astronauts visiting could end up charged with basalt…..
My new desktop background. Many thanks!
Clearly Mars believes that acid-washed denim will be making a comeback this spring fashion season.
To be serious though, I DO remember reading about one of the rover designers, who was concerned about possible electrostatic discharges from the Martian dust devils. There was no documentation at the time about electrostatics with Terrestrial dust devils, so he went into the desert with some instruments and documented thoroughly.
A lot of people who initially had disparaged the notion were shocked, so the rovers received extra protection against ESD and were shut down in the early mission when dust devils came their way.
I don’t know if they still shut down Opportunity when dust devils are heading its way.
The picture is beautiful. I love the dunes and the blue ripples. The ripples make me want to go swimming.
Embiggen! I love it. 8-}
Embiggen: I love it! 8-}
Embiggen! I love it. 8-}
Where are the expert comments from Richard C Hoagland ?
What is that artefact on the lower left? In the shadow in the left corner? It looks like an termite hill with tentacles? Maybe there are mites on mars, which ate all the plants?
Umm, body paint,,,
,,,or tattoos. Either is good for me,,,
Great pics,,,
Gary 7
A new quilt top – that’s what the first photo looked like to me without thinking about it. So I’m glad to know Mars looks beautiful in blue. O my gosh.
Great image – although it could almost easily be a photo from above the Sahara, Namib or Great Sandy Deserts here on Earth as much as Mars.
Where are those tell-tale martian
canalscraters?Quoted for truth – very well said and seconded by me.
Wzrd1 (6) said:
Heh. So were you thinking of the colour or the cyanate anion?
Enaresenate? I thought it was enbarsoomenate for Mars?