Mars is sublime

By Phil Plait | November 4, 2009 7:30 am

Mars is weird. It’s small, and cold, and has a thin atmosphere that’s almost entirely carbon dioxide, and what isn’t CO2 is nitrogen and, bizarrely, argon.

So you expect to see weird landscapes. But even so, Mars has the potential to be really, really weird. Check this out:


That slightly disturbing image (click to embiggen) is not a microscopic picture of a scientist’s colon (at least, not as far as you know). It’s actually a region near the Martian south pole. It was taken with the HiRISE camera on the Mars Reconnaissance Orbiter, and the area shown is roughly 700 meters across (about 0.4 miles).

What you’re seeing are layers of the polar ice cap. The ice is mostly CO2. Mars is so cold that a lot of the cap persists throughout the year, and is called the residual cap. Some of it does sublimate, though, which means it goes right from a solid to a gas. Underneath that layer is something more solid, perhaps water ice, that does not sublimate. As the upper layer partially goes away, it leaves these weird Swiss-cheese-like patterns, revealing the smooth layer below.

This image only shows a small portion of a much larger area where this occurs. Here’s the "context image", a zoom out if you will:


I marked the rough outline of the zoomed image in this one (it’s rotated about 90 degrees counterclockwise in the zoom). You can see that this odd terrain (aresain?) goes on for kilometers. It really does look like some sort of bacterial colony. But it’s actually the result of millennia, maybe millions of years, of constant annual atmospheric deposition and sublimation.

And just as a reminder — because I love to point this out — Mars was 250 million kilometers (150 million miles) away from Earth on August 20, 2009, when this image was obtained. Yet MRO was only 250 km above its target, yielding this fine imagery at a resolution of 25 centimeters (10 inches) per pixel. Got a ruler handy? Pick it up, hold it in your hand, and think on the fact that we have spacecraft orbiting Mars, an alien world, that can take pictures of objects on its surface about the size of that ruler.

Man. I love this stuff.

[P.S. If you like this image, the HiRISE page has wallpaper versions of it; the links are at the lower right at that link.]

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (65)

  1. Daniel J. Andrews

    My first thought was that it was freeze-fracture electron microscopy of a cell. Google it and compare. That is really a cool Mars pic.

  2. Bouch

    Cool picture, amazing stuff. One question: From that picture I can’t tell if I’m looking at mountains or craters here. Is the smooth part higher than “swiss cheese holes”, or are those mountains with the smooth part a valley where more sublimation occured?

  3. Juergen

    Nitpick: something the size of a ruler will not be picked up. Something the size of the ruler squared will be picked up… something the width of the ruler would be too small.

  4. I’m having a hard time figuring out the topology too. I assume the round bits are meant to be the swiss cheese holes then? I assumed they were like hillocks. Especially tricky for me to view them as holes on the lower image.

  5. GT

    How long before somebody thinks these are “elf runes” set out by the Martians to communicate with us?

  6. Peter

    Looks like a giant swine flu virus…

  7. MNPundit

    Hmm, nothing on China saying the militarization of Space is inevitable?


    Phil Plait:

    I marked the rough outline of the zoomed image in this one (it’s rotated about 90 degrees clockwise in the zoom).

    Err… Phil, I think that you meant to say: it’s rotated about 90 degrees anti-clockwise (or counter-clockwise, as you guys in the U. S. call it) in the zoom.

  9. Pathfinder's Airbag

    How long before someone gets all excited about TWO MORE FACES on Mars? (Lower right hand corner, two frowny faces, one with a nose.) I smell Coast to Coast…

  10. Why is argon bizarre? About 1% of the Earth’s atmosphere is argon.

  11. Gus Snarp

    OK, I know you astronomers and space exploration fans are going to disagree with me here (ok, I don’t know it, I just think some of you will), but what bugs me about this is that we have better imaging of Mars than of Earth. There is not a publicly available set of imagery of the Earth at this resolution. There are private satellites that have visible spectrum images under a meter, but not 25 centimeter. I’m certain there are military satellites with visible spectrum imagery at least this good, but for publicly available multi-spectral or even visible spectrum imagery we have much, much lower resolution.

    I think it’s great we can image Mars at high resolution. I just wish we could get the funding for a new, stable, high resolution, multi-spectral satellite to image the Earth.

  12. I downloaded the image and rotated it – I’m 99% sure they’re hummocks, not craters (they’re UP from the flatter surface, not down) based on how the shadows fall onto the flat surface.

  13. Peptron

    You can go on this site:
    There are some locations of the Earth (like where I live) where the resolution is probably even better than 1 cm per pixel.

    Looks like a giant swine flu virus… FROM MARS!

  14. Cool [oops,pun] picture.
    However, the title of this post reminded me of a ‘wanna’ T-Shirt inspired by this book I’m reading about how the Earth will end… something about ‘Death’….

    Neutron Stars: The Universe’s Degenerates.


  15. Aerimus

    @12 Gus Snarp:

    Without commenting on the availability of publicly available high res images of earth (I’m sure that other will), I can say that I doubt most astronomers or space exploration fans would not want to see such resolution turned on the Earth. The Earth, afterall, is just another planet, and it still has a lot to tell us about itself and the universe beyond.

  16. Dawn

    I predict a new “Face on Mars” controversy with the ‘frowny face’ in the lower right. 😉

  17. Sanity

    So, how big are those pictures? in kilometes I mean.

    @12 Gus Snarp
    Those pictures are available, but pictures of the Earth are much more profitable than pictures of Mars. For that simple reason, people prefer to sell them instead of giving them away.

    There’s also a privacy problem. Do you really want those pictures of your house and your backyard to be publicly available?

  18. Matt T

    @12 Gus Snarp: I think the DoD might take issue with having a publicly available database of hi-res shots of EVERY US military installation. Not to mention Dick Cheney’s house. On the flip side, Martians don’t seem to care much that we can see them sunbathing in the back yard. At least, they haven’t said anything about it yet.

  19. Gus Snarp

    @Sanity – They’re not available. Find me a source of 25 centimeter imagery of Earth, even for pay. But beyond that, scientists studying the earth cannot afford the high resolution imagery that does exist. But HiRISE includes an IR band, can you find me an IR band image of earth at 25 centimeter resolution? Sure, imaging the Earth is profitable, imaging Mars is not. But creating a government funded scientific imaging mission for Earth is worthwhile, whether private companies are doing it or not.

    As to privacy, well there are already higher resolution images of urban areas available to the government, so if you’re worried about big brother – too late. But really, 25 centimeter imagery of your house or backyard isn’t going to show anything that is a real privacy concern. You can’t see faces or naked body parts at that resolution. There’s also temporal resolution. For there to be a real privacy concern one would have to imagine that these images were taken frequently, they wouldn’t be. Plus, most scientists would be more interested in images of places without houses.

    My issue here is this: The U.S. government funded a series of satellites (Landsat) to image the earth for scientific purposes. The imagery went through a variety of levels of availability, but was always relatively cheap compared to commercial satellites. Now it is all free (hurrah!). Unfortunately the last Landsat satellite was launched in 1999, and it is broken. Landsat 6, launched in 1993, never reached orbit. The only fully functional Landsat is Landsat 5, launched in 1984.

    There is a lot we could still learn about the Earth from better publicly available satellite imagery. I have no problem with sending an imager to Mars, I just think we should put some money into a better earth imaging satellite or two.

  20. Gus Snarp

    @Matt T – There are commercially available (very expensive) high res imagery available (though not as high as the HiRISE imagery of Mars). They are pretty much as high resolution as you need for military/intelligence purposes. In fact, NATO uses those sources pretty much exclusively, because using U.S. military imagery means they can’t always share it with all NATO members. Increasing that resolution and making it cheaper is not going to change the security situation. And since I’m advocating a government satellite, the government can easily smudge out sensitive installations, or even just turn the imager off when it overflies them. It’s not hard.

  21. Gus Snarp

    Sorry about all that. Really, this imagery is cool, let’s just do Earth too.

  22. ColinB

    ok, so exactly WHICH link of the many on that page yields me a 25cm/pixel image? Can someone draw a picture of Dick Cheney’s house on the photo, for scale?

  23. Gus Snarp

    @sanity – assuming the images are on the HiRISE website in their native resolution (which I think they are), then the smaller image is 197.6 meters across the long side and the larger is 756 meters across.

  24. Gus Snarp

    Nevermind that, I made a stupid mistake on the sketch. That would have been a 1/100th scale sketch of the house.

  25. Jason

    As far as imaging Earth goes, How far down can you go in resolution from Orbit before trying to peer through a few dozen kilometers of fairly thick atmosphere intereferes?
    I think Weather on earth is a Significant deterrent to continuous high-res visible imaging. I remember a blurb about the Whole earth image doen at night by NASA. I think it was mentioned it took Months if not a couple of years to finally get Clear, and night time images of the entire planet.

  26. Gus Snarp

    @Jason – We’re pretty good at atmospheric correction. Sure, you have temporal issues, it may take lots of overflights to get a good clear image of a given site, but we can certainly get one.

  27. Trebuchet

    I’m surprised no one has pointed out that the hi-res images on G0ogle Maps and Google Earth are taken from aircraft, not from orbit.

    That said, I just zoomed in on my house. (No, I’m not going to provide a link.) At the best overhead resolution, I’ve estimated my truck is 14 pixels wide. In real life, it’s less than 2 meters. That’s about 14cm per pixel. Again, that’s from an airplane, not from orbit.

  28. Gus Snarp

    @ColinB OK, here’s a sketch of Cheney’s former residence overlaid on the image for scale:

  29. Gus Snarp

    @Trebuchet – I believe you are correct there. Google’s imagery has been acquired in a haphazard fashion, picking up whatever they could get free or on the cheap, so there is a mix of public satellite imagery, private satellite imagery, and, rarely, aerial photography. The best satellite imagery is usually just under 1 meter resolution.

  30. Trebuchet

    Gus, I think all of Google’s highest res imagery is from aircraft, probably from USGS surveys.

    And for those concerned about privacy, when I try to zoom in one step too far it switches over to “street view”. I can darn near read my license plate. They drive around your neigborhood taking pictures.

  31. Gus Snarp

    @Peptron – I don’t know where you live, but I have never seen a 1 cm per pixel image of any location on earth, even from aerial photography. The high res aerial photography that is available is mostly of urban areas and covers a very limited portion of the earth’s surface. To get the raw data is prohibitively expensive, and to get it for the area you need if it doesn’t already exist – well you can forget about that on a research budget. Also, an image in Google earth is mostly useless for serious scientific analysis. Scientists need to be able to process the imagery themselves, work with individual bands, and to be really useful we need more than just the visible spectrum.

  32. Keith (the first one)

    How deep/tall are those things? (I can’t tell if they’re hills or valleys)

  33. Timothy Reed

    There are more considerations to mapping Earth vs. Mars than just comparing a single maximum resolution value of 0.25-m for HiRISE and 0.5-m to 0.6-m for WorldView and QuickBird, the highest resolution commercial imagers. A lament that we don’t do the same for Earth as we do for Mars fails to account for the myriad of objectives that each is designed to perform. It’s not just a question of money, it’s a whole array of conflicting objectives that must be weighed against each other in the design process. HiRISE must be able to distinguish features that will assist in the understanding of planetary processes where there is no chance ever that corroborating ground information will be collected. That’s an entirely different objective from the imaging requirements of commercial Earth-observing satellites.

    In order to do this there are tradeoffs. Before fretting too much over the relative qualities of the images, it is important to look at some of these. An important one in this discussion is coverage; HiRISE will only ever map ~1% of Mars’ surface at 1.2-m resolution, and only ~0.1% at 0.3-m. So to say we have better imaging of Mars than of Earth is false; there is more commercially available imagery of Earth from DigitalGlobe at higher resolution than there is of Mars from HiRISE. I’d even make a gentleman’s wager that the amount of free material from Google Earth and Google Maps of the Earth easily outstrips HiRISE as far as percentage of the planet imaged that is at a higher resolution.

    Having been intimately involved in the design and assembly of the optics of all three of these instruments, I am immensely proud of their capabilities and of the many hundreds of people who worked tirelessly to put them into orbit to give us such wonderful imagery and insight into two different worlds.

    Timothy Reed
    Principal Optical Engineer, HiRISE, WorldView, QuickBird

  34. BMoreKarl

    For future reference on this and a lot of similar extra-terrestrial terrain – a simple note about where the light is coming from would answer all these questions. Perhaps astrographers could agree on a convention that a discrete yellow arrow always means sunlight angle.

  35. Gus Snarp

    @Timothy Reed – I am in no way denigrating any of those instruments, but I still say that the U.S. Government has been woefully lacking in investment in imaging of the Earth for scientific purposes. All advancements in Earth imaging of a non-secret nature in the last decade (at least) have been made by other nations or private companies that charge significant amounts of money for their data. I understand the difference in the missions, and I don’t think we need exactly the same imagery, but I do think we should be investing more in imaging earth. One might argue that what we already have on earth is adequate for most scientific purposes that now exist (I doubt it, but it might be), but even so, no one had any idea what scientific discoveries the telescope would lead to when it was invented. We should do our best to advance imaging technology and to turn the results of that advancement on the Earth in hopes that entirely new ways of using it will in turn be discovered (because they will).

  36. Strahlungsamt

    Calling Richard C. Hoagland? Are you there Hoagland???


    I repeat!


    and pot is now legal in America 😉

  37. Jay Fox

    The capability to resolve detail at this level was not invented just for this mission to Mars. The incredible resolution is obtained in two ways. First, I believe this satellite is pretty close to the surface, as compared to satellites orbiting our own planet. Closer equals better detail. The less dense atmosphere promotes lower orbits and visual clarity.

    Getting closer with an inferior camera doesn’t help much, so they put a really good camera on board. How good? Well, the US military has stuff the rest of us don’t even know about yet. Back in the late 70’s and early 80’s, intelligence satellites were beaming digital images of incredible resolution to ground stations, where the data was converted back to images with truly mind-blowing detail. A truck in one of those images was more than 8 or 10 pixels.

    What made this all the more interesting, to me, was that in the late 90’s, while working in the semiconductor industry, a new laser production device was delivered to the plant that I worked in. The company techs showed great enthusiasm as they demonstrated this latest, cutting edge technology for imaging tiny details. They had just re-invented something I’d seen in the military twenty years before.

    The technology already exists for imaging the finest details you could imagine. It is hideously expensive, though, and can only be financed by very deep pockets. That said, only strategically important areas would ever be considered for imaging. Your back yard probably would not be considered. And the images being digital, anything considered sensitive could be dithered to reduce detail locally, so don’t expect anything released to show detail of Cheney’s house.

    The cameras loaded onto these space missions are probably closer to designs used by government intelligence than they are to privately developed technology. Just a guess here on that one, but it seems to me that compromises have to be made to some degree. They could probably get even better resolution but lack the bandwidth to get the images from there to here.

  38. Gary Ansorge

    Hey Phil Shouldn’t that title be:


    Gary 7

  39. Bacterial colonies? Well, yes, I could see that. In fact, I’ve seen more than a few colonies in my time:

    But that “zoom back” image is a pareidolia wonderland! Several people have already mentioned the faces, but right next to the red rectangle is ET in an X-ray view with his digestive tract visible. The upper right and lower left look to me like cell mitosis (?) or whatever its called when the chromosomes pull apart during reproduction. And could that be the FSM in the bottom center?

    Man, I gotta back off from the herbal teas.

    – Jack

  40. Damon B.

    It’s the Valley Dor!

    But with resolution that good, we should be seeing Plant Men. What’s the deal?

  41. Markle

    In case somebody wants some actual numbers, the best commercial Earth-observing satellite imagery is 50cm. That’s by statute not physics. GeoEye-1 can do 41cm/pixel panchromatic greyscale and 1.65m 3 color, but it’s illegal in the US to provide commercial images better than 50cm.
    That’s satellites, though.

    If you can get an overflight, an aircraft can get you your 1cm. Here’s the classic watering hole shot in Chad. You’ve now seen it Gus. 1cm tricolor. Think his mommy would recognize him?

  42. Ray

    While I understand Phil’s comment about having 25cm imagery of Mars, I have to ask “What would we use it for?”

    And are there really any features on Mars that we need to see at that level of resolution?

    For that matter, the same can be asked of Earth.

  43. Chris A.

    @ Bouch, Alex Whiteside, Emory Stagmer:

    They are most definitely round holes. The giveaway is the fact that you can see the edge of the shadows cast by the rim of the holes perfectly paralleling the rim’s shape in the holes’ bottoms. The light source (the Sun) is at the lower right in the first (zoomed in) image, and at the left in the context image.

    But my brain is still having a hard time grepping the geometry of the regions opposite the shadowed edges, where the brownish “rind” appears.

  44. Gus Snarp

    @Markle – Yeah, you can get anything you want from an airplane, balloon, whatever. We’re talking about satellites here, and you’ve verified what I said – there is not publicly available satellite imagery that good.

    But once again, I never meant to say we needed this exact kind of satellite or this exact resolution in the first place (though my post does sound that way). What I want is a new, higher resolution version of Landsat. A working satellite with multi-spectral imaging that is funded by U.S. tax dollars and makes its data freely available. In a perfect world we would have a hyper-spectral imager on board too. The resolution need not be 25 centimeter, but better than 30 meters would be nice.

  45. Gus Snarp

    @BMoreKarl, Bouch, Alex Whiteside, Emory Stagmer, Chris A.:

    The table below the image on the HiRISE site states: that the angle of solar incidence is 77 °, with the Sun about 13 ° above the horizon. Now if only their was an indication of which direction on the image is 77 degrees, then we could clear this all up.

  46. Gus Snarp

    @Markle – OK, I did say aerial photography there. I certainly had no idea they had loaded anything that high-res in google, but it doesn’t change the fact that it’s a specifically tasked aircraft mission, not something that enables much in the way of scientific inquiry. Apparently the plane is low enough that people on the ground have noticed it and are staring up at it. Clue me in here, the image copyright is TerraMetrics. Why did they give this one aerial photo to Google?

  47. Paul Schrum

    Clearly the formation is a finger pointing us to where we should land to look for the Martian archeological site.

    (Since I am new to this blog, I should say that the above sentence is tongue-in-cheek.)

  48. Gus Snarp

    And for the record, how cool is it that I’m actually having some form of conversation with the guy who designed the optics for these things?

  49. The MRO is 250 km above the martian surface, yet it can take pictures with much better resolution than LRO, which is just 50 km above the lunar surface. Is there such a big difference in their cameras?

  50. Chris A.

    Try this: Rotate the image 135 degrees counter/anti-clockwise, and the fact that the round features are holes becomes much clearer (to my eye/brain, anyway). We’re wired to expect the light to be above us, with shadows pointing more or less downward.

  51. Alhemapu

    Totally looks like a map from Starcraft.

  52. Jay

    Gus: It’s my understanding that the military has access to imagery and the resolution you describe, but it’s not generally available to the public for a number of reasons.

  53. Bob

    At the far left center of the larger image (the same one with the two frowny faces in the bottom right) there is the word “Allah” written in Arabic. There are also some vaguely Arabic letters/words at the top center.

  54. Petrolonfire

    Eeewwww! *NOT* so pretty a picture!

    Sure that ain’t your colon? (Checks to see if I’ve been in a nearly year-long coma w /o realising & its suddenly April 1st.)

  55. Flying sardines

    Mars is weird.

    Hey Mars probably thinks Earth’s weird y’know! 😉

    It’s small, and cold, and has a thin atmosphere that’s almost entirely carbon dioxide, and what isn’t CO2 is nitrogen and, bizarrely, argon.

    Well Argon is inert and heavy, very non-reactive and, okay its a bit rareish, but bizarre? Why?

    BTW. Why argon though and not xenon or krypton nobelly-gas-speaking? Or is that the bizarre part?

  56. 1) The pedant in me had to run and look up the definition (if there was one) of embiggen. OK I obviously missed that episode. I like it. I learned another new word this week. imput. The payroll company upgraded from DOS to Windows and imputted my 50/50 split deposit as an absolute value instead of percentage.

    2) The fractal self-similarity just screams out at you doesn’t it? I posted a long rambling blog that was partially based around this quote from Thoreau:

    When the frost comes out in the spring, and even in a thawing day in the winter, the sand begins to flow down the slopes like lava, sometimes bursting out through the snow and overflowing it where no sand was to be seen before. Innumerable little streams overlap and interlace one with another, exhibiting a sort of hybrid product, which obeys half way the law of currents, and half way that of vegetation. As it flows it takes the forms of sappy leaves or vines, making heaps of pulpy sprays a foot or more in depth, and resembling, as you look down on them, the laciniated, lobed, and imbricated thalluses of some lichens; or you are reminded of coral, of leopard’s paws or birds’ feet, of brains or lungs or bowels, and excrements of all kinds. It is a truly grotesque vegetation…You find thus in the very sands an anticipation of the vegetable leaf. No wonder that the earth expresses itself outwardly in leaves, it so labors with the idea inwardly. The atoms have already learned this law, and are pregnant by it

  57. consider the round items to be trees, flash frozen. The land between as meadows. Other as grass land surrounding buildings. You gotum better explanation?

  58. mike burkhart

    this is incredable yes mars is weird but so is venus and io and eurpoa and titan (Phill how about having a survey have people who visit the blog list the ten wierdst things in the universe ) we have seen stranger things on mars for example the canales that were thought to have been dug by martians untill space probes showed there were no canales and lets not forget cydona theres still people who think the hills and moutans there are martian city . buy the way I think there is to munch imangeing of the earth just go to google maps type in your adress and clik satalite view you will see a nice view of your house

  59. Timothy Reed

    @ Lucas: “The MRO is 250 km above the martian surface, yet it can take pictures with much better resolution than LRO, which is just 50 km above the lunar surface. Is there such a big difference in their cameras?”

    In a word, yes.

    But to reiterate, the goal is not to provide the best imagery possible, but imagery that satisfies the mission requirements. This answers Ray’s question–

    “While I understand Phil’s comment about having 25cm imagery of Mars, I have to ask “What would we use it for?”
    And are there really any features on Mars that we need to see at that level of resolution?

    –in that the science objectives of HiRISE are to characterize the current climate and mechanisms of climate change, determine the nature of complex layered terrain, identify water-related landforms, search for sites showing evidence for aqueous and/or hydrothermal activity, an identify and characterize sites with the highest potential for landed science and sample return by future missions. Those high level science requirements drive the imagery resolution.

  60. it looks like H1N1 girms and ugh its so ugly and discusting it looks like doodo ewwwwwww

  61. Imagine what the government has to look through…


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