Just another incredible Mars image…

By Phil Plait | June 18, 2006 11:35 pm

The European Mars Express probe continues to amaze. Check out the image above: it’s one piece of an excruciatingly large image (warning: huge download of a 5500×2500 pixel image!) of Apollinaris Patera, a volcano on Mars. In the above picture, all you’re seeing is a smallish section of the caldera– maybe 22×18 kilometers (roughly 14×11 miles).

The obvious thing to see is the double crater. What could cause such a thing? My first thought was, unlikely as it might be even on the heavily-battered surface of Mars, one crater was already there, and another impact caused the second crater. I even figured the crater on the upper right was older: it has more smaller craters in it, while the lower left crater is more pristine. Older stuff has more time to accumulate craters inside.

But this seemed unlikely to me, since both craters are about the same size, and they don’t really overlap: where they meet, the rims are straight.

The problem here is that we’re too close; we’re too zoomed in. Take a step back, as it were, and check out the overview:

Now take a look at the double crater in context. See the raised rim in a circle all the way around both craters? You get features like that when an impact melts ice under the surface, causing mud flows (volcanoes can make this pattern as well, but those two guys are pretty clearly impact craters). So these craters formed at the same time. It looks to me like this was a binary asteroid or a comet, an object that had either split in two or was two objects in orbit around each other. They would have hit almost simultaneously, blowing out those two pits and causing that apron of outflow material. The presence of smaller craters inside the upper right one may just be coincidence.

Or, I might be totally wrong. If this were a supernova remnant I’d be on more solid ground (ironically, I suppose), but areology isn’t my forte. Still, the point is there is a lot to see on Mars, and with the new probes going there taking incredible high-resolution shots (this one is at 11 meters per pixel!) it sometimes helps to step back a little and get — literally — a bigger picture.

P.S. For those with broadband, and I mean broadband, there is a 14 Mb 3D anaglyph of this image as well that is way cool.’

CATEGORIZED UNDER: Astronomy, Cool stuff, Science

Comments (17)

  1. Obviously the Martian’s were making a giant figure 8 or infinity sign as a way to tell us …. something … or it’s a game of cosmic darts and the big circle is the bulls eye. :)

    Cool photo. I was thinking double impact as well when I saw it. It’s amazing that you have 5 major impact craters that fall in nearly perpendicular lines like that. Is it likely that all 5 impacts were from the same event, or would this have happened over years or millions of years?

  2. Mark

    Another sign of Martian intelligence. Obviously the beings that constructed the monolithic Martian astronaut face also have a fondness for snow men. :-) (Just kidding)

  3. gopher65

    The top one looks older to me. Notice how the mud flows on the bottom one appear to encroach on the mudflows of the top one?

  4. Hi. hello i’m from Brazil!!! Kiss

  5. aTom

    This is clearly a giant Martian microbe (macrobe?) caught in the process of mitosis. You can even see the chromosomes! 😉

  6. TheBlackCat

    It’s Spectacle Rock! Ganon’s going to KILL US ALL!

    Probably too early to reach that conclusion yet, but if they find one that looks like a giant turtle I’ll start getting worried. Although if Ganon’s hideout is there it would explain why our probes keep failing.

  7. Is it just me or is there a third crater in a straight line projection from the “twins”? If so this looks like a stream of debris hit the planet and not just one object. Could the asteroid/comet have broken up first ala P73?

  8. Melusine

    The bottom crater’s shadows show it’s much deeper–I’m trying to get a visual on a binary asteroid doing that. Puzzling. They are cool photos indeed. The 14mb is beautiful. Did you see the Rover’s panorama image on Emily’s blog? The false color blue sky makes it look eerily familiar. Very neat though.

  9. These craters obviously announce the impending arrival of Cthlulhu. I’m sure now that I’ve mentioned it, everyone will see it too….. };>


  10. eddie

    Now, Phil, you know what to do. Anytime any Mars image puzzles you, the answer is obvious; just pick up the phone and call RCH. I’m bettin’ HE’s got a theory!

    Kidding, of course. Really cool photo.

  11. icemith

    I don’t know about anyone else, but for the first five minutes, I could not resolve the first image of the ‘twins’. They are cool images, but they looked like pimples or slightly raised domes. And I was aware of it, persisted, knew what to expect, but just couldn’t make the ‘crater’ depression happen!

    Reading on, the next wide image appeared, and immediately was able to see the crater, in fact all craters. Paging back up, the original twin image resolved into craters proper. I have noticed this effect (or is it defect?) before, and I wonder if others have this problem.

    Now I also wonder how long before we get the latest image sensor for cameras into space, especially the 111 Megapixel unit just released by Dalsa Semiconductor Company with others for the US Naval Observatory for use in Astronomy. It’s a four inch square sensor ( 100mm square). Imagine that in your day camera! What resolution. I only read about this yesterday in the email from dpreview magazine. Somebody may be able to post a proper link, and any other information.


  12. icemith

    Interestingly, if the image is rotated 180 degrees, I can immediately resolve it. Must be something to do with the lighting angles/ shadows etc and what we normally expect to see in the usual overhead lighting arrangement.


  13. Phil, why is the colour tone of the anaglyph is different than the upper image? By the way, do you mind to have link exchange with my blog?

  14. ty pex

    The features inside the craters look like erosion due to water flows. Would that also be due to mud, or might they have been cut at a later time?

  15. Robert Carnegie

    Something funky going on under the surface? There’s supposed to be frozen water down there that sometimes thaws and scooshes out, right?

    I think the one that puzzles me more is the one that looks like a river canyon, but it starts and ends inside the crater. It doesn’t go anywhere. Did they start building a canal there and then they decided it was in the wrong place anyway?

  16. Joey

    areology. at first i thought, it was a “study of areolas”

    but a little googling corrected me though.

  17. If they were simultaneous impacts, why would there be a division between the two craters?


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