Tag: engineering

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Cool image time! The photo on the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on October 7, 2019. In one image it encapsulates the process that forms one of the more intriguing and major Martian geological features, dubbed chaos terrain.

Chaos terrain is typically a collection of mesas separated by straight-lined canyons. It is found in many places on Mars, most often in the transition zone between the southern highlands and the northern lowlands where an intermittent ocean might once have existed. It is believed to form by erosion, possibly caused by either flowing water or ice, moving along fault lines. As the erosion widened the faults, they turned into canyons separating closely packed mesas. With time, the canyons widened and the mesas turned into a collection of hills.

This image shows the beginning of this process. It is centered on a fault line running from south to north. In the south all we can see is the fault expressing itself as a very shallow small depression in the plains. As we move north the depression widens and deepens. The material inside the depression near the top of the photo could very well be a buried inactive ice glacier. Several million years ago, when the inclination of Mars was much higher and the mid-latitudes were much colder than the poles, the water ice at the poles was sublimating from the poles to those mid-latitudes where it fell as snow. At that time this glacier was likely active, helping to grind out this canyon.

The image was taken at the south border of a chaos region dubbed Nilosytis Mensae, as shown by the overview maps below.
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Cool image time! The image to the right, cropped and reduced to post here, is one of those terrain sample images the science team of the high resolution camera of Mars Reconnaissance Orbiter (MRO) takes periodically when they have a gap in their observation schedule with no specific requests for images of the terrain below. Still, they need to use the camera regularly to keep its temperature maintained, so they then take a somewhat random picture over that terrain, based partly on information from lower resolution images but without a strong sense of what they will find.

In this case, they found what I dub pimples, raised mounds with small holes at their peaks. The image, taken on November 30, 2019, is located is in the northern lowlands, at a latitude (45 degrees) where subsurface ice is possible. Thus, we could be looking at water ice volcanoes.

Very few high resolution images have been taken of this area, with no others close by. Thus, the overall context of these mounds is hard to gauge. They could be widespread, or very localized.

The unknowns here and general lack of research suggests this location and these mounds are ripe research for some postdoc student interested in planetary geology.

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Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) last week released a very neat short movie compiled from images taken of an impact crater located on top of the northern polar ice cap of Mars. As noted by planetary scientist Alfred McEwen of the Lunar & Planetary Laboratory in Arizona in the image caption,

Shown here is an impact crater on the north polar ice cap, which contains an icy deposit on the crater floor. These inter-crater ice deposits shrink and expand or change shape or surface texture from year to year,

The image on the right, cropped and reduced to post here, is the most recent of these six images. The crater, which is about 200 feet in diameter, is the black speck in the center. The white streaks to the south of the crater, similar on all six photos, indicate that the prevailing winds come from the pole.

The animation zooms in on the crater so that you can see the details on its crater floor. And though the animation is fun, below the fold is a collage of all six photos, which I think makes it easier to see how the inter-crater ice deposits changed from summer to summer.
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Cool image time! The image on the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on October 7, 2019, and shows a crater on the northern fringe of Arabia Terra, one of the largest transitional regions between the Martian northern lowlands and the southern highlands. It shows a crater with an inlet canyon that makes the entire crater resemble a wiggling tadpole.

This is certainly not first tadpole-resembling crater found on Mars. See for example this press release from February 2018, showing a tadpole crater with the tail being an outlet channel. In today’s image however the channel feeds the crater.

In fact, take a look at the full image. This crater apparently occurred right at the edge of a large mesa cliff, with this impact cutting into the cliff near its bottom. The canyon might have actually existed before the impact, with the crater merely obliterating the canyon’s outlet.

If you look along that escarpment to the east you can see similar southwest-to-northeast flows. One is a canyon flowing downhill through the escarpment, probably resembling what the first canyon might have once looked like before the impact. To the east of this is another tadpole crater. This second tadpole impact however took place on top of the mesa, so the channel flows out from the crater and then down off the mesa, the reverse of the tadpole crater above.

These flow features are consistent with the nature of this transitional zone, a region with many features suggesting it was once the shoreline of an intermittent ocean. That ocean, if it had existed, is long gone, though scattered across the Martian surface are geological ghost features like these that speak of its past existence.