Tag: Mars

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Cool image time! The picture to the right, cropped to post here, was taken on February 21, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). This is a terrain sample image, which means it was snapped not as part of any specific research project but to fill a gap in the schedule in order to maintain the camera’s proper temperature. As usual, the camera team tried to pick something of interest, and I think they succeeded.

The two large depressions in the center of the picture do not resemble impact craters. They have no rim of ejected material and their shape is very distorted. Instead, both appear to be places where a top layer of ice/debris has sublimated away into gas, exposing a lower layer of glacial material that itself is sublimating away to form the bumpy mounds that fill the floor of the depressions.

The white dot inside the inset box on the overview map above marks this location, just south of the northern wall of a large 30-mile-wide canyon, with its northern floor even more depressed, as if the material in that raised middle a flat pile of glacial debris flowing to the southwest after leaving the gap in the crater to the northeast. An MRO context camera picture taken on January 6, 2016 gives a wider view, showing that there are a lot of these type depressions on the surface of this wide middle upraised floor, as well as some obvious impact craters.

This location is in the mid-latitude band where many glacial features are found. In this part of the southern cratered highlands there is also a lot of evidence of top layers sublimating away, as if the glacial material is a large buried ice sheet that is beginning to disappear at places where it has been exposed by impacts or shifting motion. The depression in the picture above appears to be an example.

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

To put it mildly this is strange terrain. The curving east-west feature resembles a glacial flow, but it also has features that say otherwise. For example, what could cause that gap in the middle of the picture? Such things are not usually seen in an ice flow. Then there is that filled crater on the center left edge of the picture, inside the flow. Though filled with material, the flow itself does not flow around the crater, suggesting the impact occurred after the flow. Moreover the crater is a pedestal crater, whereby the surrounding terrain has eroded away so that the crater ends up standing above it.

These facts suggest that this flow is very old, and has not flowed for a very very very long time. This in turn suggests it isn’t ice but solidified lava, though for a lava flow it also has features that are anomalous when compared to typical flood lava on Mars.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labeled this a “Circular Outcrop of Bright Rock.

What I see is a Martian skin rash. Based on the ripple pattern below the ridge one might think we are looking at sand dunes, except that the rash above the cliff has no such pattern. Instead, the ground in this one particular area looks very roughened in a random sort of way.

The location at 27 degrees south latitude suggests there is little near surface ice at this location to cause this feature. The overview map below provides another but not very helpful possibility.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 7, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the camera team labels a “sinuous ridge within valley.”

The location is at 30 degrees south latitude, right on the edge of the southern of the two 30-60 degree mid-latitude bands where orbital images show many glacial features. Closer to the equator and there is little or no evidence of near surface ice on Mars. Farther from the equator from this latitude and the evidence of near surface ice increases, becoming very dominant the closer to the poles you get.

At this spot, it appears there is little near surface ice. The channel has ripple sand dunes inside it, and the sinuous ridge appears to be bedrock. Similarly, the plateau above the channel also appears like bedrock, the craters showing no evidence of splatter that is common where there is near surface ice.

What made the channel? And what made that a sinuous ridge inside it?
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on March 26, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is labeled by the scientists “Brain Terrain on Floor of Crater in Warrego Valles.”

Brain terrain is a geological feature entirely unique to Mars that remains unexplained in any way by geologists. The scientists know it is almost certainly related to near-surface ice and its sublimation into gas, but their theories as to its precise formation process remain incomplete and unconvincing, even to them.

In this case the brain terrain’s interweaving nodules seem to show flow patterns, but strangely those patterns go around depressions and hollows. Yet, the overall flow direction also seems to point downhill towards the slope on the image’s right edge.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on January 17, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) by the camera team not as part of any particular research project but in order to fill a gap in the camera’s schedule so as to maintain its proper temperature. In such cases the camera team tries to pick potentially interesting spots.

This cliff, about 1,100 feet high, is the north wall of a major volcano channel flowing across the Tharsis Bulge, the lava plains that surround Mars’ giant volcanoes. Located in the dry equatorial regions, there is no near surface ice here, but a lot of dust, much of it likely volcanic ash. In the full picture are several ancient craters, all of which are almost entirely buried by this dust and ash.

The cliff wall itself is made up of numerous layers, each representing a past volcanic flood lava event that covered this region with a new flow of material. These events occurred over more than a billion years.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on February 21, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as “dipping layers”, referring specifically to the mesas with the terraces on their western flanks.

The layers obviously signify past cycles of geological events on Mars. That the terraces are only on one side of the mesas suggests that they are tilted, with the downhill grade to the east.

These layers however pose several mysteries. First, why are they located so specifically in only certain places of this region? It appears that the layered terrain is only found in the lower hollows and valleys. Why?

Second, why are they tilted at all?
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on January 15, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an area where the ground suddenly transitions from a crazy quilt of criss-crossing hollows and ridgelines to a very flat and smooth plain.

The location is at 21 degrees south latitude, so this is in the dry equatorial regions. Though it has a small resemblance to the chaos terrain that is found in many places on Mars, mostly in the mid-latitudes where glaciers are found, the scale here is too small and the ridges and canyons are not as sharply drawn. While chaos terrain usually forms sharply defined large flat-topped mesas with steep cliffs, here the ridges are small and the slopes to the peaked tops are somewhat gentle.
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Because Mars Reconnaissance Orbiter’s (MRO) CRISM instrument needed to be cooled to low temperatures to use infrared wavelengths for detecting underground minerals and ice on Mars, and the cryocoolers have run out of coolant, the science team has shut the instrument down.

In order to study infrared light, which is radiated by warm objects and is invisible to the human eye, CRISM relied on cryocoolers to isolate one of its spectrometers from the warmth of the spacecraft. Three cryocoolers were used in succession, and the last completed its lifecycle in 2017.

All the remaining instruments on MRO, including its two cameras, continue to operate nominally.

In its final task, CRISM produced a global map showing water related minerals on Mars, released last year, and a global map showing iron deposits, to be released later this year.

Cool image time! The picture to the right, cropped and reduced to post here, was taken on March 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and was taken not as part of any specific research request but by the MRO science team to fill a gap in its schedule while also maintaining the camera’s temperature. Sometimes these somewhat random times show nothing of interest. Sometimes they are fascinating, as in this case.

The photo shows what appear to be a spray of small impacts on an easily melted surface. Imagine spraying hot molten lava on a sheet of ice. Instead of creating a crater with an upraised rim, on impact each droplet would quickly melt a hole.

Did these small impacts all occur at the same time? My guess is yes, based on the overview map below.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

At first glance I thought I was looking at a variety of eroding glacial flows. I was completely wrong. This terrain is located on the floor of 900-mile-long Ares Vallis, thought to have been carved eons ago by some flow, either liquid catastrophic floods or glacial ice, but is now located in the very dry equatorial regions of Mars.

Then what caused these meandering ridges? The overview map below, plus the wider view of MRO’s context camera, provides us more data but little illumination. In fact, both leave us more questions and mysteries.
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From Argyre Basin to Hellas Basin is about 7,000 miles.

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 25, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists labeled this image “Crater fill”, but that hardly suffices. First, the fill appears at first glance to resemble peeling paint. At closer inspection, rather than peeling paint we have instead a collection of ridges vaguely resembling cave rimstone dams that either enclose a blob-shaped region or simply meander about until they reach the crater’s interior rim.

The crater interior itself appears largely filled with material so that its rims are subdued. The location, as indicated by that black dot near the center of the overview map above, marks the location at 49 degrees south latitude, in the middle of the cratered southern highlands of Mars where many craters have strangely eroded interiors.

What makes this crater however more puzzling is that none of the surrounding nearby craters look like this. A context camera image taken March 23, 2019 shows that while some of the nearby craters have what appears to be glacial material in their interiors, none exhibit these meandering ridges. This crater stands unique, for reasons that are utterly unknown.

Are these ridges a manifestation of the glacial material filling the crater? Or are they bedrock sticking up through that glacial debris? Your guess is as good as mine.

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Today’s cool image to me illustrates how the presence of near surface ice in the high latitudes of the northern lowland plains of Mars helps to produce a very strange and alien terrain.

The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a typical example of what the scientists have dubbed a “pedestal crater,” where the crater ends up higher than the surrounding terrain because the impact had packed the ground and made it more resistant to erosion.

This theory however does not explain entirely what we see here. That apron mesa surrounding the crater also resembles the kind of splash field that is created when an impact occurs in less dense ice-rich ground. Note too the soft stippled nature of the ground. Wind erosion is not the sole cause of change here.
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