Sand dunes march across Mars

By Phil Plait | March 4, 2010 3:39 pm

I’ve said this before, but it bears repeating: when I was a kid, Mars was a dead planet. Dry, frozen, with hardly any atmosphere, I always figured it wasn’t very interesting.

Heh.

Mars may or may not be alive in the biological sense, but it’s certainly active geologically! And images from the Mars Reconnaissance Orbiter’s HiRISE camera verify it. It’s spotted migrating ripples across Martian sand dunes:

hirise_dunemarch

These before and after images (part of a trio of them) show the motion. The image on the left was taken June 30, 2007, and the one on the right in October of that year. During that time, just a few months, the ripples can clearly be seen to have moved by a few meters (the inset diagram shows the ridges on the dunes schematically). This means that the wind blowing in this part of the planet is not only actively pushing around the sand, but also doing it on a timescale we can measure.

And on a spatial scale, too. Note the scalebar in the images: it’s 20 meters long, about the size of a house! This strongly suggests that these dunes are loose piles of sand, and not heavily crusted over or cemented (the grains stuck together). That, plus the time and size of the migration, yields yet more clues about the way the surface of Mars is put together.

Amazingly, this comes at the same time as other news showing that dunes in another region of Mars haven’t moved for at least 100,000 years, and possibly as long as three times that age! So while some regions of Mars are dynamic, active, and changing on a timescale of weeks, other regions are static, unchanging, and rigid for hundreds of millennia.

I used to think Mars was uninteresting. I was dead wrong. Mars is weird, and in astronomy and space exploration, weird is always interesting.

Image Credit: NASA/JPL-Caltech/University of Arizona/International Research School of Planetary Sciences

CATEGORIZED UNDER: Cool stuff, Pretty pictures, Space
MORE ABOUT: dunes, HiRISE, Mars, MRO

Comments (28)

  1. jb

    ok..
    now did a human notice that or a computer..if human, I gotta say he has good eyes :)

    Imagine scouring images to look for that..I couldn’t do it!!! ;)
    jb

  2. Levi in NY

    Weird is always interesting no matter what the subject. I try to maximize my personal weirdness in my daily life. Sure, it alienates some of the normal people, but I only want to hang out with other weirdos anyways.

  3. Mars IS weird. Weird cool :)

    It’s fascinating how Mars just keeps on amazing me, with all our new discoveries.
    Sure it isn’t the fantasy land that we’ve seen in movies, but this is just so much cooler. Mars is a changing planet just like our own :)

  4. Levi in NY

    @jb: It would be a lot easier to spot the differences if you flicked back and forth between the old and the new image. Pluto was discovered using this method. http://en.wikipedia.org/wiki/Blink_comparator

  5. “What the Frak?” Is the question which has lead to the most scientific discoveries in human history.

  6. Now all we need is a mars rover that will be built like and jumps dunes like a dune buggy. That’ll be kewl! Oh! How about a Baja Bug Rover! Even better!

  7. Mike C.

    Neato stuff. Perhaps James Cameron could film the remake of Michelangelo Antonioni’s “Zabriskie Point” there, though he’d have to change the title to that of another Antonioni film, “The Red Desert.”

    Sorry for the puns, I’m trying to give up smoking.

  8. wildride

    Dr. Manhattan was right!!!

  9. @jb

    I thought the same thing. Good eyes or a lot of time on their hands. Then again, they could’ve found it the boring way like Levi said. :)

  10. Uselesstwit

    Robert that is brilliant. Dune buggy + low gravity = awesome fun.

  11. The “boring and uninteresting” always turns out to fascinating. I remember how the moons of Jupiter and Saturn were just “Dirty Iceballs”. Boy did Voyager change that.
    I remember the Moon was a dry place that didn’t have the elements to support a base, that was 5 years ago.
    I can’t wait to see what close-ups of Ceres show us.
    The most fascinating discoveries come from place we thought were boring.

  12. jb (#1): In fact, this was part of a program specifically designed to look for dune changes. The link at the top of the post explains it.

  13. Eric TF Bat

    Phil – how do you feel about the ecological quandary of the Red/Green/Blue Mars books, viz the debate between terraformers and those who wanted to maintain Mars in its original state as much as possible? I’d love to hear your thoughts on that: should we make other planets in Earth’s image so we can live there even if it means losing a lot of what makes them unique?

  14. I almost went to that talk here at LPSC. Then I decided a quick nap was more important. :-

  15. T_U_T

    should we make other planets in Earth’s image so we can live there even if it means losing a lot of what makes them unique?

    Yeah, moving dunes are something completely unique, nothing like that can be found here on earth. A terrraformed mars would not have things like deserts either. It would be just a copycat earth. Nothing more, nothing unique. Move along folks. Biosphere SOOO mundane. sterile deserts are precious and unique and should be protected from degradation by life. We are working as hard as we can to protect and expand them here on earth too…

  16. Marcello

    i was wondering… proving that dunes move is, from a logic point of view, simple: you get many pictures in sequence and confront them…
    but how do you prove that dunes have been in a specific position and configuration for the last 100/300K years? do you have some info or link about this part of the post? :)

    Thanks!
    Marcello

  17. Pieter Kok

    Eric TF Bat, that is a good question. Right now we do not have the knowledge to do successful terraforming, and I doubt we will ever find the necessary resources to terraform and entire planet.

  18. I wonder how the conspiracy theorists who claim that these dune systems are actually alien ‘glass tubes’ will handle these results? Either NASA are photoshopping images to cover-up “anomalies” (as NASA always does :P ) or parts of the tubes are moving … somehow?

    Conspiracy theorists are too cute. :)

  19. “Good eyes or a lot of time on their hands.”

    When I got my degree, these detection systems were called “grad students”.

    The apparent change of the sharp slip-face in the lower left of the images is also interesting. My guess is that dune field is located at the top of the slip-face, due to the way the streaks *appear* to source from the “ends” of dune ripples (dunes migrating right off the edge to trigger small slides?), but it’s notoriously hard to tell in a small area short like this (no craters, so is the lighting coming from the top right? or the lower left?).

  20. Bryan Feir

    anothermike@5:

    Or, to quote Isaac Asimov:

    The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…’.

  21. DLC

    Bah! Clearly that’s elevation changes from where the ancient Martians moved the rock they made the Face On Mars out of ! you can’t fool me! quantum vortex hyperspacemath proves it!
    and I used to work for NASA* !!!!

    *(as long as you consider a day trip to KSC in FL to be “Working for” )

    But seriously, folks: It’s great, seeing imagery from Mars and knowing people are gaining knowledge about the place, even if I don’t live to see Earth travelers visit.
    thanks , Phil.

  22. when I was a kid, Mars was a dead planet. Dry, frozen, with hardly any atmosphere, I always figured it wasn’t very interesting.

    Kinda like how when Neil DeGrasse Tyson was a kid, he knew that there were about six stars in the sky, and they weren’t very interesting? How’d that work out for the two of you? :-)

  23. Gary Ansorge

    Ah, the Red Sands of Mars,,,where have I heard about red sand dunes before? Oh, I remember. The Rub Al Khali in the Empty Quarter of Saudi Arabia. 800 foot tall red sand dunes, with not a (detected) drop of rain in a century. I wonder if the same processes occur there as on Mars? Note that there is life in them thar Arab dunes, from scorpions to dung beetles to lizards and snakes. So MAYBE there might be something alive on Mars that fills the equivalent eco-niche???

    Stay tuned for updates,,,

    13. Eric TF Bat

    I expect, long before we have the ability to terra form planets, we’ll have decided to just build whatever we want in space colonies, from 20 km long, 20 km wide rotating cylinders to hollowed out asteroids with cities (and countryside) inside. A lot easier than remaking an entire planet.

    GAry 7

  24. Coalbanks

    Before humans canfigure out if/how to terra – form mars or other planets they might want to figure out how to get there without being changed grnetically or just killed by radiuation.

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