Mars has depression.
Well, a depression. You’d have one too if you had a great gaping pit on your surface that seems to defy explanation.
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| A bowl-shaped pit on Mars. Click to brobdignangify (or get the original version). Courtesy NASA/JPL/University of Arizona. |
Isn’t that awesome in 3D? Use red/green glasses (red on the left) to see this in all its bichromatic anaglyphic glory. This is a red/green stereo pair from the HiRISE camera onboard Mars Reconnaissance Orbiter, my favorite camera in the solar system right now.
This crater-like feature is located in what’s thought to be a mud flow, near a volcano. It’s almost certainly not an impact crater, since it lacks many of the features associated with impacts (no raised rim, for example). It looks like the surface collapsed, which makes some sense. There could have been water or ice under it, and some volcanic event happened to remove it, which also removed the support. Whoomf! Sink hole.
Concentric rings are common in such things, due to the way the material falls in on itself (watch a video of an ant lion digging a pit in sand and you’ll see similar features). But if you look around it, you see radial features called rays. Those are usually due to impact events which throw out streamers of materials! But rays are also usually thin, a layer of dust coating the surface. These rays have depth and width, as if they are from something flowing out of the pit.
I’m no geomorphologist, so I’m guessing, but I wonder if the collapse of the denser surface forced lower density water up, filling the depression with water and making it overflow the pit. Think of jamming a sock into a nearly full glass to get the picture. Or maybe water was squeezed out of the layers just below the surface, and it flowed away, boiling in the low pressure. What a sight that would be!
I don’t think it’s all that easy to say exactly what happened here. But the 3D view might give scientists some insight into what happened here — it provides them with the angle of the sloping sides, for example, as well as how much volume was lost, which can be used to get information about the collapsed material.
And in case you didn’t notice, the rippling in the very center? Those are sand dunes. So very cool.
February 2nd, 2009 at 7:19 am
Pareidola moment: looks a little nipply on Mars in that picture.
February 2nd, 2009 at 7:26 am
Now I’m glad I bought those plastic 3D glasses someone recommended here recently.
Charles Boyer: yep.
February 2nd, 2009 at 8:05 am
Um, what’s the scale, Phil? How far across is this feature? How deep at the center?
February 2nd, 2009 at 8:05 am
brobdignangify?
February 2nd, 2009 at 8:32 am
Without the glasses it looks like a raised feature, not a depression. The glasses solved that one.
February 2nd, 2009 at 8:49 am
Look like a sinkhole to me.
Of course, that’s what the, um, mutant ex-Nazis who made it to Mars with the secret Von Braun clap drive in 1944 *want* us to think it is, along with their, uh… Gray Alien co-conspirators.
Does it lie on one of Hoagland’s mystical pandimensional ley lines? You know, the ones that create the hexagon at Saturn’s pole.
February 2nd, 2009 at 9:07 am
What I want to know is – is the Sarlacc in residence?
February 2nd, 2009 at 9:14 am
http://en.wikipedia.org/wiki/Sidoarjo_mud_flow
“It is expected that the mud eruption will last for years to come and the area will experience a significant depression, forming a large caldera.”
February 2nd, 2009 at 9:38 am
I knew I should have nicked those 3d glasses from the IMAX… (Not really stealing since they throw them away anyway)
February 2nd, 2009 at 9:38 am
If you wear the glasses backwards you can make it a mountain!
February 2nd, 2009 at 9:43 am
Looks like an initial impact from the radial stuff around the hole, then loss of material like a deeper layer of ice, maybe by evaporation after the impermeable cap was broken. If so, it should get bigger over the centuries.
February 2nd, 2009 at 9:50 am
Looks like the oatmeal I had this morning.
February 2nd, 2009 at 9:57 am
Maybe one of the pharmaceutical companies that makes anti-depressants could sponsor the next mission?
February 2nd, 2009 at 10:09 am
“brobdignangify” ?? Tired of “embiggen” already?
Some coffee-snorting comments here this morning. Thx Charles Boyer.
“Here I am, brain the size of a planet, and not ready for my close-up”
February 2nd, 2009 at 10:15 am
Reminds me of a Yellowstone mud pot bubble that just burst. Then it somehow froze in that state. When the bubble first bursts it leaves steep walled hole where it came up through the mud and the bursting thick mud bubble leaves radial spokes. I could then see if you could nearly freeze things the walls would then slump like this to partly fill in the round hole this created. How to get it to freeze fast enough is the problem. Radial spokes would flatten some as well. Still I wonder if something akin to that happened. But there should be more, not just one.
Like others I saw it as a mound at first (rare for me with craters) but once I saw it with glasses I could no longer make it a mound without them. Try as hard as I could I can’t find a Madonna or Jesus. Darn.
February 2nd, 2009 at 11:28 am
It’s obviously an old open pit mine. Compare it against satellite pics from GoogleEarth.
)
February 2nd, 2009 at 11:58 am
^ Or it’s the entrance to one of those underground cities that some folks say exist on Mars.
February 2nd, 2009 at 12:36 pm
It does look like it is a raised feature, and in fact it looks more like a raised feature that was processed with the red/blue colors reversed (which can happen sometimes). If it is a feature that extends downward into the surface, the center area should be at least somewhat darker, not lighter. Also, the darkest shadowy areas around the “rings” don’t blend well against the highlights, looking like dark gashes that float higher than it’s bordering surfaces. Also, it just doesn’t look right with surrounding surface.
I’ve done quite a bit of 3D artwork in my days (shutter glasses, lenticular, alaglyph, stereo pairing, etc) and this strikes me as an error, just that it was simply processed with the red/blue reversed. If you flip your glasses (wait a moment for your eyes to re-adjust for the color shift) and all the discrepancies go away; all the surfaces work together far more naturally. That’s far from definitive so i’m certainly not saying it IS an error (anaglyphs can look reversed sometimes due to lighting, differences in materials, image resizing, etc), but i’d like to get more information before i buy this being something other than a very interesting raised feature.
February 2nd, 2009 at 12:40 pm
Looks like a fossilized Brachiopod
February 2nd, 2009 at 1:01 pm
More guesses:
The ‘rays’ could simply be a pattern from splashing – throw a bucket of mud into the air and see what happens when it hits the ground. Look for active ‘mud volcanoes’ on earth and see if any of them bear some resemblance to their Martian cousin.
February 2nd, 2009 at 1:02 pm
Phil’s used “brobdignangify” before.
I can’t recall where my specs are, but that thing looks like the stuff I had to shave around on my upper lip this morning.
February 2nd, 2009 at 1:15 pm
Looks like a collapsed volcanic caldera. The radial features are visible on the collapsed areas indicating they were there before the collapse and not a later event.
February 2nd, 2009 at 1:35 pm
I don’t have 3D glasses, so I don’t have altitude information to check this idea against, but it looks to me more like the rays are from material flowing _in_ to the sinkhole, rather than out. Possibly after the collapse, fine sand ran downhill into the depression, giving the appearance of channels carved by liquid flow.
February 2nd, 2009 at 1:50 pm
Ditto what Sundance said about the direction of flow. What the channels remind me of is what happens when you scoop a hole in a water-saturated material, like mud. The water in the mud around the hole flows in to fill it, and the mud left behind compacts. The channels are not really eroded out, they just kinda look like they were.
February 2nd, 2009 at 2:10 pm
Looks like a volcano, but with lava being sucked in…
February 2nd, 2009 at 2:13 pm
Should this work with the 3D glasses they handed out for the Superbowl ads? It’s not working for me.
February 2nd, 2009 at 2:27 pm
Wait a second, this *is* a raised surface. Look at the shadows: if this was a pit, the bottom left of the object would be lit, not the upper-right. Compare this to the little divots at the lower left side of the picture: those are indentations and they appear lit from the bottom left.
Also, when you put on your 3D glasses you’ll notice that the planet surface is L+R aligned, but surface features are negatively offset, meaning you have to cross your eyes to line them up. Going from neutral to crosseyed means that we are looking at something closer than the planet surface.
February 2nd, 2009 at 3:47 pm
It looks like a sinkhole to me, and I’m sitting about ten blocks from a sinkhole that ate a house. I downloaded the photo, put on my red/blue glasses and flipped it, rotated it, reversed it and squinted at it–it still looks like a sinkhole. It definitely goes down, and the terrain around it is depressed enough to get surface flow into it. The surrounding flow is pretty obvious, too, so there’s either water or dust going in. It could be where a block of underground ice melted, which is called a kettle lake or pond here on this planet.
February 2nd, 2009 at 4:41 pm
I don’t have 3D glasses here but if you look at the lighting of the two smaller features to the right of the sinkhole they are lit the same way. I’m assuming those features are craters, they look very much like it – so the large feature must be a depression as well… wanders off to find some coloured cellophane.
February 2nd, 2009 at 4:46 pm
My gut says it’s definitely taller than the surrounding landscape, but it’ll be interesting to find out from a different pass/angle/etc. 3D effects like this are harder to determine the more one looks, as the longer the brain starts to become convinced which way the depth is working it gets set in our perceptions. I wonder if there is any more data on that particular feature?
Were the superbowl glasses red/blue or the amber/blue? I didn’t see it myself, but had i known there was a 3D commercial i might have watched.
February 2nd, 2009 at 5:56 pm
It’s a giant frog. I for one wish to be first to welcome our new giant martian frog overlords.
February 2nd, 2009 at 6:01 pm
@Santoki: Those little “divets” in the lower-left must be raised features. Rather, compare the depression to the craters on the right.
February 2nd, 2009 at 7:27 pm
Two words: Anaconda Copper.
- Jack
February 2nd, 2009 at 7:33 pm
Wow!! I fiddled with the resolution on my monitor and got a better view, and it is most *definitely* a deep hole, not the raised feature i was “seeing” before. Mostly it was the cliffs where the surrounding terrain is separating into chunky cliffs; that was reading to my eyes an entirely different kind of shape. Dayum, this is a cool image! How large is the whole depression?
February 2nd, 2009 at 8:29 pm
If I look at it long enough, I get a sort of Pareidola moment of my own; it looks like a maw.
So, would this mean Mars is hungry? Are Mars Bars still around? Or just Milky Ways?
February 2nd, 2009 at 8:40 pm
Hey, it’s a particle beam strike. Just like the Richat Structure. You can see the signs of battle all over the solar system!
February 2nd, 2009 at 8:52 pm
Yeah, I’d call them amber/blue.
February 3rd, 2009 at 6:56 am
Well, if we ever need to get rid of a pesky bounty hunter, we know where to go.
February 3rd, 2009 at 9:53 am
Of course if W was still in office, we’d be wincing every time he said analglyphic
February 3rd, 2009 at 10:25 am
I agree with Jack/Daniel; you can almost see the little dumptrucks.
February 3rd, 2009 at 10:26 am
Well, looks to me like someone started to weld something and then stopped after the initial touch. Looks exactly like that actually. . . . inter-planetary lightening? or plasma lightening (if such a thing exists) – intense energy would be needed to create something like this if you ask me . .
February 3rd, 2009 at 3:16 pm
If it were convex rather than concave I would swear that it is a cow chip. Remember the cow that jumped over the moon. Maybe one jumped over Mars. Dusty
February 3rd, 2009 at 7:04 pm
I isolate the blue and red parts and pasted into an image:
http://img22.imageshack.us/img22/7595/mars3dxf8.png
You have to cross your eyes/stare into space like a Magic Eye poster – you may have to back away from the monitor for the two images to come together, but your eyes should lock in once you have.
February 4th, 2009 at 5:45 am
Perhaps the rays and the sink hole were created at the same time by the same event. You said it is in an old mudflow. If the mudflow was caused during a volcanic event, then it is possible that a basin of boiling or near-boiling water (or watery mud) created from melting earlier in the same event could have been overridden by the later mudflow. Steam from the hot water would could then have built up under the thicker mud from the boiling water (or watery mud) underneath, forming a bubble. The bubble then ruptured, spewing out a mix of water and mud, forming the rays. Then, as the mud and water in the basin cooled, and the water evaporated, it contracted and was no longer able to support the thicker mud over top of it, causing the sink hole a few weeks later.
Sound plausible?
February 5th, 2009 at 4:15 pm
I hope you realize, Phil, that you made me look up the word “anaglyphic”.
You kids these days and your synonyms for “stereographic”!
February 5th, 2009 at 5:24 pm
I have to admit I thought this was a raised feature when I first looked at it – my first thought was, “The Zit On The Face On Mars”.
February 6th, 2009 at 6:23 pm
Indeed, I have a terrible problem even looking at ordinary craters on pictures of other planets. They all look like domed bumps to me, sticking out rather than sticking in. I have to trick my eyes into seeing them the “other way” until they pop into view properly.
February 9th, 2009 at 7:23 am
It’s obvious, the soviets used to secretly detonate nukes on mars!!!
Vela wasn’t thinking big enough!!!