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Ice-filled Martian sinkhole

Ice-filled pit on Mars
Click for full image.

Cool image time! The pit shown in the high resolution photo to the right (image rotated, cropped, and reduced to post here) was taken on January 25, 2021 and labeled by the Mars Reconnaissance Orbiter (MRO) “Collapse Pit in Graben with Ice Fill.”

There is a lot of information in that title. First, a graben is a geological feature where a section of terrain drops relative to the surrounding terrain, producing a depression. Second, it appears the graben in this region is mostly filled with debris, probably wind-blown dust or sand or volcanic ash.

Third, at this particular spot the filling material sank, like a sinkhole on Earth, creating the pit.

And fourth, and maybe most intriguing, the scientists think that this pit is now filled with ice. At 47 degrees north latitude, the location is prime for such ice, and the interior material resembles similar glacial features seen in many other mid-latitude craters.

Overview map

The black box in the overview map to the right marks the location of this pit. Note the long fissures running to the northeast from the shield volcano Alba Mons. It is thought as this volcano bulged upward, it caused these fissures as the ground expanded by the pressure from below. The fissures are the graben referenced above.

Though the fissure at this location is mostly filled, the sinkhole suggests that there may be voids below. If so, there is the chance that an underground facility could be build here, protected from radiation and the harsh swings of temperature on the surface. Digging into it and creating a stable habitat within it might not be easy, however, as the fill material is likely structurally weak. It might be like trying to build something permanent in the sand of a beach.

Or not. We really don’t have a good handle on the properties of the material here. All this image really tells us again is that there is ice readily available in the mid-latitudes of Mars.

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.


  • mrsizer

    I’m seeing a hill, not a pit. The shadows don’t seem to match up with the indented ring to right. I trust that you are correct, but it looks strange.

  • mrsizer: If you download the image and turn it upside down the pit will likely become evident to you. This phenomenon is an optical illusion caused I think by where we think the sunlight is coming from. Your mind is insisting the light comes from the east, when it really is coming from the west.

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