The artwork of the Martian landscape

By Phil Plait | October 15, 2009 11:28 am

It’s been a while since I’ve sung the praises of the Mars Reconnaissance Orbiter’s HiRISE camera, which takes incredibly hi-res images of the surface of Mars. Thanks to the HiRISE Twitter feed, I found this incredible picture:

Can I get a Holy Haleakala! from the congregation?

Wow. I mean seriously, wow. You really really want to go look at the embiggened version. What you’re seeing here are sand dunes on Mars. This region is in the center of a large crater at mid-north latitude on Mars, a couple of hours past local noon, and with a resolution of 50 cm (18 inches) per pixel. Sand dunes are common in crater beds, where the wind can blow steadily across the surface and sculpt the ever-present sand into those flowing sculptures.

But what this picture so spectacular are the graceful blue-gray swirls arcing across the dunes. These are caused by dust devils, which are a bit like mini-tornadoes. If the ground gets heated, rising air can punch through cooler air above it. This starts up a convection cell, with warm air rising and cool air sinking. If there is a horizontal wind the cell can start spinning, creating a vortex like a dust devil. I’ve seen hundreds of these on Earth, and they are wonderful and mesmerizing to watch.

The important thing to note here is that the sand in the craters of Mars is actually dark grey in color, since it’s made of basalt. The reason it looks red in pictures is because covering the sand is a thin layer of much finer dust, and the dust is what’s red. When a dust devil moves over the Martian surface, it can pick up the very light dust particles, but not the heavier sand grains. So those blue-grey swirls are tracks where the dust devil has vacuumed up the dust, revealing the darker sand underneath. If you look carefully in the tracks, you can see the sand dune ripples are undisturbed. Only the dust is gone.

There’s more to see in the picture as well. There is a sloping dune peak cutting across from top left to lower right (it’s more obvious in the larger context view of this region), and again more dark streaks, linear this time, probably caused by sand sliding down the dune face. When the sand moves, the dust covering it gets disturbed and once again you see the darker color of the sand itself. I also love the way the dune shapes change depending on where they are in the picture, caused by differences in the wind patterns across the floor of the crater.

When I look at pictures like this, I am smacked in the face with the cold, hard fact that Mars is a world. It’s not just a dot in the sky, it’s not just a set in a movie, it’s not just pictures from a space probe. It’s a planet, a vast complex system of interacting environments which produces climates, landscapes, vistas, weather.

And man oh man, does it produce beauty, awe, and wonder. Wow.

My thanks to Dr. Alfred McEwen of HiRISE for taking the time to explain to me the difference in color between the dust and the sand, and how that affects this image.

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (80)

  1. The sloping dune peak looks like a bar code.

  2. Lee

    I thought this was the reveal of your tattoo. Looked (on my BB) like skin and tattoo ink and the top left like the top of your, um, bum. Very happy to be wrong!

  3. This should have been your tattoo’s design.

  4. Crux Australis

    That *actually* looks like the inferior aspect of a pair of tattooed breasts.

  5. Disclaimer

    “But what MAKES this picture so spectacular…”?

    And, yes, wow. I mean seriously, wow!

  6. Yoweigh

    The dark streaks look a lot like the shadows of plant life to me, but of course that’s only because my brain can’t comprehend the scale.

    @Crux: So the blue streak is some deep cleavage or something? :)

  7. At first glance, I thought you were showing off your new tattoo.

  8. FLAnatic

    I think those are sandworm tracks…where’s the spice?

  9. Yoweigh

    FLAnatic wins the thread.

  10. Kevin

    Wow. This is now my desktop background at work.

  11. You have a Holy Haleakala! and more from this member of the congregation!

    And I’ll just echo the tattoo comments.

  12. Dee

    Is there something in the photo that looks like a stretched out UPC code ribbon? A reflection or something?

  13. Efogoto

    The pattern of the dunes put me in mind of the loops and whorls of a fingerprint. Pareidolia, but fun.

  14. Alec

    Is this the first conclusive evidence of major cleavage on Mars?

  15. This is clearly a shadow cast by his holy noodliness, the Flying Spaghetti Monster. All praise his noodly appendage. Ramen.

  16. Wow. Gorgeous.

    Just a few minutes ago, I thought to myself, “you know, I really need a new desktop background. I wonder if the Bad Astronomer can provide.” Clickity click, “AWESOME!”

    The downside is that out of the corner of an eye (like, say, the dozens of people walking past my desk), it looks a tad bit like a super-zoomed naked body… Which I suppose it is, just not a HUMAN body.

  17. Can’t even think of anything to say. There’s really nothing TO say after seeing that, except that I’m so glad to be alive.

  18. Thomas Siefert

    Ditto the tattoo and cleavage comments, you might want to notify Richard Wiseman so that he can do his poll thing on this.

  19. This image reminds me of sketches of Mars by 19th century observers like Giovanni Schiaparelli or Eugene Antoniadi.

  20. Julie

    It looks more than a little bit like some of the old drawings of the infamous Martian canals to me. I don’t suppose anything of those whorls would be large enough to be seen from Earth, but that’s what it brings to mind to me.

  21. Mike

    What the hell, man. I thought this was an anti-anti-vax blog, what’s all this astronomy crap?! That’s it, I’m leaving.


  22. ttrygve

    Speaking of tattoos, when are we going to get the big reveal?!

  23. Christina Viering

    I was thinking the same thing everyone else was-looks like a tat! But it would make a great wallpaper, too!

  24. This reminds me of the paintings of what were once thought to be ‘canals’ on Mars. Very cool!

  25. Donnageddon

    Beautiful, but I still don’t quite understand what that blue-ish “mist” is?

  26. becky'sthoughts

    @FLAnatic: You are awesome!!

  27. When I look at pictures like this, I am smacked in the face with the cold, hard fact that Mars is a world. It’s not just a dot in the sky, it’s not just a set in a movie, it’s not just pictures from a space probe. It’s a planet, a vast complex system of interacting environments which produces climates, landscapes, vistas, weather.

    Beautiful words to accompany a gorgeous image.

    I once took an intro course in planetary geology (so I’d know Valles Marineris, Hellas Planitia, or maybe Alba Patera if i saw them), but I still had no idea what this was. Thanks for the lesson! Amazing.

  28. KC


    Someone is definitely channeling Percival Lowell and Schiaparelli!

  29. Rory Kent

    Can I see a Spice harvester at the top right?

    But seriously, that is SPECTACULAR! Really makes you think about how special our planet is. Mars is so similar, yet so uninhabitable.

  30. Erotca from Mars!
    I like it.

  31. Spencer Attridge

    eeek my mind can’t comprehend the scale of it.. ditto this equates my wallpaper now and that I am glad to be alive to see it.

  32. My jaw dropped, for reals.

  33. JoeSmithCA

    At first I was going to say, “Ok Phil is playing a prank on us and showing us a really funky tatoo on a woman”. My wife thought the same. Funny thing is that even after showing her the full image, she said “Ewwwww a parasite!”

    No, that’s Mars silly!

    Very cool, thanks for sharing Phil!

  34. Charles

    @Lee #2: I also thought for a moment that it was a tattoo, albeit one done by a drunkard. And that fold of skin at the top does look very bum-like.

  35. Must. Go. There. NOWWWWW!!! (I’m holding my breath until we do.)

  36. Sorry. I can’t make sense of this picture. It looks like a closeup of a weedy garden, and the diagonal blue thing looks like a double exposure. Are you sure this is Mars?

  37. Patti

    Seriously, guys, I don’t see what you see. I see what looks like a reflection of water on the right side, worms (like tapeworm, roundworm, etc.), two sets of DNA or one long barcode with an X at the left end, an upside down foot, and a crying eye. I wish I could get a bigger screen shot.

  38. Brango

    So, every painting requires a painter, eh.

    Maybe we should ask Ray Comfort who painted this.

  39. Patti

    It looks like a beautiful work of art to me (surrealist: Chagall or Dali are two that remind me of this look.)

  40. Markle

    Its like the inverse of the pressed blueberries in Gusev. But writ really large. Cool.

  41. fred edison

    Whoa! Truly an amazing and beautiful shot of a dynamic and different world.

  42. Owen

    Holy frikkin’ wow. That is just unbelievably cool. How much is a ticket to get there? Oh wait…

    Someone should really get this as a tattoo…

  43. How much is a ticket to get there?

    About 1500 times less than the price of waging war against Iraq.

  44. Just me

    WOW. Incredible! I never cease to be amazed at all the cool things we can do, all the astounding things we’ve been able to discover and the discoveries yet to come. I wish I could live a few hundred generations so that I could see where our journey takes us.

    Um. Okay. It doesn’t make a whole lot of sense to be amazed at discoveries yet to come, but I didn’t get much sleep last night.

  45. There are certain aspects of this picture that could possibly be used for an ad for Victoria’s Secret.

  46. Stunning. Can’t.Speak.


  47. Mars, a beautiful place, and utterly and completely dead.

    And we are destroying the only known living planet with breakneck speed.

    Cognitive dissonance, people.

  48. Ausduck

    seriously, Phil this is way cool! I sent the picture to my 14 yo twin nephews who could not believe it and think they have a really cool awesome auntie. :)
    And of course, the really cool awesome BA has two new fans 😀

  49. Buzz Parsec

    I agree with all the tattoo comments. I just hope Richard Hoagland doesn’t find out about this!

  50. Nigel Depledge


    Well done, HiRise!

    Spectacular image. Thanks, indeed, BA, for drawing this to our attention!

  51. Lars

    That picture reminds me of the chest of the waitress at the local metal rock pub. She’s got some sweet tats.

    @kuhnigget: To a layman like me, your calculations seem highly plausible. Hadn’t it been for the Dune reference earlier in this thread, I’d declare it a w00tz0r.

  52. Mike

    KC Says:
    Someone is definitely channeling Percival Lowell and Schiaparelli!

    My thoughts exactly!

  53. Astronomynut

    Who else sees a lake at top of the bottom fourth of the full size image? Just below the dark band. I’d be interested to hear what that is. I know it’s not, but it sure looks like a giant lake.

  54. Luke Dudney

    Instant desktop wallpaper.

  55. Grizzly

    The blue stripe is actually a downslope. Consider that it is a couple of hours past noon. Light coming from the left, the blue is illuminated from there.

  56. Kristjan

    This revelation would suggest that the so called “wet patches” on the sides of some hills on Mars are not water seepage, but in fact dry landslides that simply are exposing the darker soil underneath.

  57. FlowersInHisHair

    I see these swirls and I think: good candidate for geek-tattoo.

  58. Bahdum (aka Richard)

    I saw a documentary show on TV one time talking about super weather, or something along those lines. Anyway, they brought up the Martian dust devils. However, they likened them to tornadoes, rather than “dust devils.”

    I think it was sensationalism in action, really.

    In the Central Valley of California, I have noticed an area that has its fair share of dust devils. They range from less than a foot in diameter to maybe four to six feet. (I’m bad at judging distance and eyeballing measurements, so take that with a teaspoon of salt.)

    They can be wispy and weak and they can be bold enough to garner shading on themselves. Even from miles away, you can make some out.

    But, I’m driving when I see them so I can only give them the briefest of attention.

    They are mesmerizing, though.

  59. Luiz Felipe Vasques

    > 50 cm (18 inches)

    I’m sorry, but it isn’t accurate enough. An inch is roughly 2,5 cm. So, making it double and suming up the half of the inch valor, we would have 45 cm.

    Just for being nitpicky, sorry.

  60. Mike Pietrzak

    Umm… air on Mars? that’s interesting.

  61. Blake

    That image looks “upside down”

    Very cool!

  62. @Mike Pietrzak Martian air is mostly carbon dioxide, there is very little oxygen in it.

  63. eternal

    damn this picture looks soooooo dirty, it looks like the freaking Y…

  64. The Mad LOLScientist, FCD


  65. algeria:

    can someone tell me wat is this??… 😀 😛


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