Tag: Mars Reconnaissance Orbiter

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Cool image time! The picture to the right, cropped to post here, was taken on June 21, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists label the strange tubelike features that are scattered throughout this picture as “landforms,” which is correctly vague because their origin is utterly inexplicable. The ground here is on the eastern slope of a small 20-mile-wide very flat shield volcano located about 150 miles northwest of the giant volcano Ascraeus Mons. The dark wind streaks point down that grade to the east, away from the shield volcano’s peak about 1,000 feet away. (If you look at the full image this indistinct peak is at dead center, with a linear depression (the volcano’s vent) beginning there and heading to the northeast for about four miles.)

Why these many tubes are all oriented in a northwest-southwest direction, at right angles to the slope, is baffling, especially because they hold to that same orientation all across the shield volcano, no matter the downward direction of the slope.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The intended science focus of the image is likely the floor of this canyon on the lower right, showing what appears to be a patch of uprised topography surrounded by what looks like glacial debris, which at this latitude of 39 degrees north is expected on Mars.

The grade at this location is downhill to the southwest, so if this is a glacier it is flowing in that direction.

The cliff is about 3,000 feet high, dropping that distance in about a mile and a half. Thus, this is only slightly less steep than the very steep cliff wall of the caldera of Olympus Mons, highlighted as a cool image two days ago.

What makes this canyon interesting — besides its spectacular scenery — is its larger context, recognized when one looks at this location from afar and thus sees how it shaped a vast portion of the global surface of Mars.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 14, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what appear to be horizontal layers in the inner wall of a small one-mile-wide and 150-foot deep unnamed crater on Mars. I have included the color version below, zoomed in to make those layers and their colors very clear.

As I have not contacted the scientists who requested this picture, I can only guess at its purpose. My guess however relates to those horizontal blue layers, reminiscent of the ice layers seen in Martian scarps at the high latitudes at about 50 to 55 degrees.

Normally it is rare to see horizontal layers like this in craters on Mars. Instead, what you usually see are downward-pointing gullies along with drainage and avalanche-type patterns, though the latter two might not be formed by either drainage or avalanches.

In this case these horizontal layers are clear and pronounced, making this crater a possibly important and somewhat unique find, based on its location.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 29, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels an “unusual shaped hill” that is estimated to be about 20 to 40 feet high.

What makes it unusual? First, it sticks up out of the endless northern lowland plains for no obvious reason, though its shape suggests the existence of bedrock topography that is now buried by the dust and debris that coats the surface of those plains.

Second, the hill itself suggests that it formed after it was covered with debris. Note the crater near its northeast cliff. It appears that the cliff chopped off part of the crater, suggesting that the hill was once level with the surrounding terrain. Some later underground pressure pushed it upward, with its angled sides determined by existing faults.

Why those forces tilted the hill upward as it did, with only its eastern fringes raised, is a question a wide view might answer.
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Cool image time! Only yesterday I posted an image of polygons in the dry equatorial regions of Mars, where little evidence of near-surface ice is found and are thought to be the remnants from a long-dried lakebed.

Today we take a look at some polygons in the mid-latitudes of the icy northern lowland plains, where near-surface ice appears ubiquitous and as it sublimates away with the changing seasons causes all kinds of strange formations, including polygons.

The picture to the right, cropped, reduced, and sharpened to post here, is a good example, centered on a 0.6-mile-wide bright crater that appears to be filled with glacial ice. The image was taken on June 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and is located at 44 degrees north latitude on the western edge of Utopia Basin. As noted by the MRO science team in 2006 for a different MRO picture with similar features:
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 26, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team calls the features surrounding these small 20 to 60 foot high hills “polygon features,” an apt description and a geological feature that is seen in many places on Mars.

When these features are found in the icy higher latitudes, it is believed they are formed in connection to the freeze-thaw cycle that causes cracks in the near surface ice. When found in the dry equatorial regions, where these polygons are located, they are usually thought to be ancient evidence of past standing water that left behind these cracks, much like the cracks seen in mud after the water has evaporated away on Earth.

The formation of these tiny hills is a bit more complex.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 7, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what planetary scientists label somewhat vaguely as “layered deposits,” because though the features inside both of these craters strongly resemble glacial ice features, until this is confirmed a good scientist remains skeptical.

I can be more bold, and call the layers glacial in both of these small and very shallow craters (less than a 100 feet deep). To explain this it is important to understand that the lighting and shadows make it hard to distinguish the high points of these layers. Based on the elevation data from MRO, the ground descends to the south, and the mesa in the southern half of each crater’s floor is actually far below the layers and material to the north.

This elevation data suggests that the layered material is surviving best against the crater’s northern interior wall, which at this latitude, about 36 degrees south, will be in shadow the most.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 1, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the camera team labels “Circular Mounds Surrounded by Moats,” which when all the known data is considered are probably caused by a spray of small meteorites landing on a field of ice.

Why ice? The location is at 37 degrees south latitude, in the cratered southern highlands of Mars, where many images show glacial-type features inside many craters. In fact, all the nearby craters at this location appear to have such features, suggesting the presence of near-surface ice trapped in these craters.

The picture actually looks at the floor of another such crater, with the mounds in the image’s upper left the crater’s indistinct central peaks. Though only 8.5 miles wide, the crater is deep, with interior walls that quickly rise 2,800 feet to the rim. That depth further suggests ice, as any snow that fell here in the far past could easily become trapped, inside what could be thought of a cold trap.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows some of the more unusual terrain found at the higher latitudes in the Martian northern lowland plains.

How do we explain this strange landscape? Based on what little we presently know about Mars, at 40 degrees north latitude this bubbly-looking surface probably indicates the presence of a lot of near-surface ice that at some time in the past was heated for some reason and thus bubbled upward to form these mounds. Think of tomato soup simmering.

Unlike simmering tomato soup, this terrain is solid and no longer bubbling. We are looking at a soup that has frozen even as it bubbled. The process could have been like an ice volcano, the ice turning to thick slurry that froze quickly, like lava. Or it could have happened fast, and then froze to remain unchanging in the eons since.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

I think the many parallel ridges are likely hardened and petrified dunes of sand because of their craggy nature. Dunes of sand would have a smoother, softer look, and in fact, if you look at some of the dunes inside the depression at the bottom-right of the picture you will see ridges with exactly that look, smooth and curved.

Nor is it unreasonable to believe these ridges are petrified dunes, as orbital data over time has found that many of the dunes on Mars, even those that look active, are not and have likely been hardened for centuries.

As for the ridges running at right angles to each other in the picture’s middle left, I have no idea. Possible we are looking at ancient dykes of lava that pushed up through cracks and faults, but this is pure guess.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 12, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists simply label as “Northern Mid-latitude Terrain”.

I have focused in on that meandering channel and the landscape around it. On Earth we would assume that channel marks the drainage of a river or stream, possibly also shaped by a glacier at some point because of its U-shaped profile. This guess is strengthened by the elevation data from MRO, which shows the channel descending to the southwest about 440 feet along its 2.2 mile length.

The channel and the eroded look of the surrounding terrain suggests strongly the presence of near-surface ice at this location, which is not unreasonable based on its 32 degree north latitude. The wider look below only adds further strength to this hypothesis, but also adds a lot more details explaining the genesis of this strange landscape.
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Today’s cool image could be labeled a “What the heck?!” photo, as the origin of its most distinct feature is utterly baffling. The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 18, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what look like a collection of meandering ridges peeking out from a terrain covered by thick dust.

The scientists label this dust-covered ground, as well as the ripple dunes to the south in the full image, “sand sheets.” Without question, the ground here seems to resemble a Sahara-like terrain. It is utterly featureless, other than the few bedrock features that poke up out of that sand. In the full image some peaks stick out, but it the meandering ridges in this section that are most intriguing. They are reminiscent of rimstone dams in caves, but what formed them remains baffling, since cave rimstone dams are formed by the interaction of limestone and water, and there is absolutely no evidence of any near surface ice at this location in the dry equatorial regions of Mars.

All the ridges signify is a buried terrain formed in some inexplicable way.
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Today’s cool image is actual one new picture and four past images, which taken together reveal something about the larger wind patterns on Mars. The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 27, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows a tiny wind-swept section of the giant volcanic ash field dubbed the Medusae Fossae Formation, about the size of the subcontinent of India and thought to be source of most of the dust on Mars.

The innumerable parallel thin ridges here all suggest that the prevailing winds blow from the southeast to the northwest. As they blow, the scour the surface ash out, and sometimes reveal the underlying bedrock, which here shows up as those small peaks and a handful of northeast-to-southwest trending larger ridges. Note too that the picture shown is only a small section of the full image, which shows that this landscape continues for a considerable distance in all directions.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on April 10, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an unnamed 1.2-mile-wide crater at about 35 degrees south latitude with what appears to be residual glacial ice hugging its north interior wall.

As this is in the southern hemisphere, the ground immediately below the south-facing interior wall of the crater is going to be in shadow the most, and thus it will also be the place where any surface or near-surface ice will survive the longest. In this case it appears that from the bumpy nature of that residual ice it has also been sublimating away. Within it however remains the faint hint of multiple layers, suggesting about a dozen past climate cycles with each new cycle producing a new but smaller layer with less ice.

The material in the southern half of the crater floor appears to be dust formed into ripple dunes.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on May 13, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists call a “channel and depression”, though to my eye everything looks like flow channels, descending to the east.

The drop from the narrow northern channel to wider southern channel is about 200 feet, with the small crater on the left sitting about halfway between. To our Earthbound eyes, something clearly flowed downhill from that northern channel into the wider channel. What we don’t know now is what the material was that did the flowing?

Was it liquid water? Glaciers? The overview map below provides some context, though it doesn’t actually provide an answer.
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Today’s cool image to the right, cropped, reduced, and sharpened to post here, provides us a glimpse at the lower mid-latitudes of Mars where the terrain is beginning to dry out as we move south. The picture was taken on April 29, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what the scientists label “large linear features.”

The main north-south ridge is only about 20-25 feet high, and its meandering nature (which can be seen more clearly in the full image) suggests it is possibly an inverted channel, formed when the bed of a former canyon gets compressed by the water or ice that flows through it, and when the surrounding terrain gets eroded away that channel bed becomes a ridge.

These ridges however could also possibly be volcanic dikes, where magma had pushed up through fractures and faults to form these more resistant ridges.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as “The tip of Cerberus Fossae,” a thousand-mile-long crack in the surface of Mars formed when the ground was pulled apart by underground forces.

If you look closely at the picture’s right edge, you can see that beyond the end of the fissure it actually continues but appears filled with material. In the full picture this however is the end of the crack. Beyond this point the ground is as smooth and as generally featureless as seen within the picture itself, and as also shown in this MRO context camera view of the same area.

Cerberus Fossae is actually three parallel cracks, with this the northernmost one. The eastern tip of the middle crack was previously highlighted in a cool image in July 2022.
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