Astronomy Picture of the Day -- Dark Sand Cascades on Mars

NASA ^ | November 25, 2012 | (see photo credit)

[SunkenCiv]

Explanation: They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The above image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first to be trees standing in front of the lighter regions, but cast no shadows. Objects about 25 centimeters across are resolved on this image spanning about one kilometer. Close ups of some parts of this image show billowing plumes indicating that the sand slides were occurring even when the image was being taken.

[SunkenCiv]

[Credit: HiRISE, MRO, LPL (U. Arizona), NASA]

[SunkenCiv]

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[onyx]

I so much love that photo, I almost want a copy to frame to hang on a wall!

[Noob1999]

Oil or tar on Mars??

Is that possible without decayed carbon based plants??

Enquiring minds, etc.

[GeronL]

how many miles does that cover?

[DManA]

Where’s that BIG BIG BIGGER THAN BIG news they promised us last week?

[fieldmarshaldj]

Looks like some funky cheese in my refrigerator.

[colinhester]

No kidding. That’s cool!

[onyx]

Truly!

[JRandomFreeper]

Looks cold. Article doesn't say whether the frost is H2O or CO. Either way... Pretty as it looks, I'd say put some Christmas lights on it, and go back to where it's warm. Don't expect the lights to look nice if I have to put them out. ;)

/johnny

[JRandomFreeper]

CO should be CO2. Doh!

[Jack Hydrazine]

I bet NASA is going to say that this isn't a lake on Mars.



And these aren't trees or bushes.

[The Cajun]

By no means land a rover there!!!
Could get hung up in the trees :)

[Beowulf9]

“Objects about 25 centimeters across are resolved on this image spanning about one kilometer”

I hate when they use these measurements because I have no idea what they mean. I cannot get any idea of the size I am looking at.

And their explanation, although I’m sure correct, does not seem correct. The dark stains appear to be standing freely in the air and do not look at all as if they are sliding down a sand dune.

Useless to me.

[Graewoulf]

Great find! Thanks!

[onyx]

I haven’t given any thought to the temperature.
I remain captivated by the photo.

[JRandomFreeper]

The picture frame is about a half mile across. Every pixel is about 10 inches. If I did my sums right. I'm just a cook.

Interpreting overhead photographs requires a rather long school in the US military.

Lots of pitfalls and tricks to it. What you think you see might not be reality on the ground.

johnny

[Ken H]

Looks like a Martian ski slope.

[calex59]

Article doesn't say whether the frost is H2O or CO

Actually the article does say. It is CO2 ice.

[Tainan]

Very cool. I set it as my new desktop. Replaces the ‘moonbow waterfall’ pic of last week(?). Thanks.