Tag: Mars

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Cool image time! The picture to the right, cropped to post here, was taken on March 16, 2024 by the high resolution camera of Mars Reconnaissance Orbiter (MRO). It was released today as a captioned picture from MRO’s camera team. As noted in the caption, written by the camera’s principal investigator Alfred McEwen:

This image shows a field a sand dunes in the Martian springtime while the seasonal carbon dioxide frost is sublimating into the air. This sublimation process is not at all uniform, instead creating a pattern of dark spots.

In addition, the inter-dune areas are also striking, with bright frost persisting in the troughs of polygons. Our enhanced-color cutout is centered on a brownish-colored inter-dune area.

Each winter the carbon dioxide in the Martian atmosphere falls as snow, mantling the surface in the latitudes above 60 degrees with a clear coat of dry ice. When spring arrives the sunlight passes through the mantle to heat the ground below, which in turn causes the base of the dry ice mantle to sublimate into gas. When the pressure builds enough, the gas breaks through the mantle at its weak points, spewing out and bringing with it dust from below, which stains the mantle with the dark spots.
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The cool image to the right, cropped, reduced, and enhanced to post here, was taken on February 22, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It gives us another example the many-layered geological history of Mars, seen in numerous locations across the entire Martian surface.

This example shows many thin layers, going downhill about 450 feet from the mesa near the bottom of the picture to the low point near the picture’s top. At this resolution there appear to be roughly two dozen prominent layers in that descent, but a closer look suggests many more layers within those large layers. Like the terrain that Curiosity is traversing on Mount Sharp, the closer one gets the more layers one sees. And each layer signifies a different geological event, possibly even marking the annual seasons, each either adding or removing a layer of dust or ice, or placing down a new layer of lava.
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Cool image time! The picture to the right, rotated, cropped, reducedl, and enhanced to post here, was taken on February 24, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Dubbed a “terrain sample” by the camera team, it was likely taken not as part of any specific research project but to fill a gap in the camera’s schedule so as to maintain that camera’s proper temperature. When they have to do this, they try to pick interesting targets, though there is no guarantee the result will be very interesting.

In this case the camera team already knew this location would have intriguing geology, based on an earlier terrain sample taken a year ago only eight miles to the south. The landscape here is a flat plateaus surrounding flat depressions, some of which appear connected by drainage channels. Today’s picture shows one flat depression with a short tail-like channel flowing into it.

Note the pockmarked surface. The many holes could be impact craters, but they also could be holes caused when the near-surface ice at this location sublimated into gas and bubbled upward to escape. Now all we see is dry bedrock, the flat ground riddled with holes.
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Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on December 21, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as an “inlet to a paleolake.” I have used this context camera lower resolution image taken January 14, 2023 to fill in the blank central strip caused by a failed filter on the high resolution camera.

The elevation difference between the plateau on the lower left and the lake bottom on the upper right is about 700 feet. The inlet channel floor is about 200 feet below the plateau. We know it is ancient because of the number of small craters within it as well as on the lakebed below. It has been a very long time since any water or ice flowed down this channel to drain into the lake to the north.

While a lot of analysis of orbital data has found numerous examples of paleolakes in the dry equatoral regions of Mars (see here, here, here, here, and here , this particular example is so obvious not much analysis is needed, as shown in the overview map below.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 4, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The ridges were the primary reason this photo was taken, as they cover a 50-mile-square region of relatively flat terrain that also appears to be a series of steps downward to the west. The dotted line on the picture indicates one of those steps downward, with the plain to the west of that line about 100 to 200 feet lower that the plain to the east.

My first guess was that these ridges might be inverted channels, but that really didn’t make sense considering their random nature completely divorced from the downward grade. Then I took a wider view, and came up with a better guess.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on February 18, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team labels this “layers in butte”, but because we are looking straight down at this 400-foot-high butte, it is difficult to see any layers at all. Based on most Martian geology however it would be shocking if this butte is not made up of multiple horizontal layers, ending with that flat surface layer at the top. Moreover, the base of the mesa to the northeast is clearly made up of a series of terraces that appear obscured at other points due to the presence of dust and dunes.

A side view would help clarify the number of layers and their thickness, but it does appear that this butte contains evidence of the geology that once covered this whole area, but over eons has eroded everything away but this butte.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on February 20, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “tilted blocks in the low northern latitudes.”

At first glance this circle of tilted blocks appear to mark a place where something erupted from below, pushing and cracking the blocks away in all directions. If there was an eruption however it appears very little if anything poured out from below. Instead, the ground inside the hollow in the center is about the same elevation as the ground surrounding the tilted blocks.

Clearly some pressure from below pushed these surface blocks upward to crack and tilt, but the answer cannot be found in this close-up picture. Instead, we need to look wider, not only at the overview map below, but at the inset on that overview map.
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Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on February 18, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as the “terminus of possible glacier-like feature.” That feature is at the lower left, at the point where glacier-like material appears to be flowing out of the channel from the northeast but then ending in an area of rough fingers.

That this looks exactly like a glacier does not guarantee that it is one, which is why the scientists insert the word “possible.” Nonetheless, the geology resembles that of a glacier, from the parallel lines along its length as well as its existence inside this channel. The location is also at 49 degrees south latitude, well within the mid-latitude strips on Mars where scientists believe many such glaciers exist.

The overview map below adds further weight to this conclusion. It also suggests that there are even more glaciers on Mars than research up to now has suggested.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 21, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled “banded terrain and layering,” it actually is a good example of “taffy terrain,” a weird Martian geological formation unique to the Red Planet that scientists as yet don’t quite understand. This 2014 paper only says this:

The apparent sensitivity to local topography and preference for concentrating in localized depressions is compatible with deformation as a viscous fluid. In addition, the bands display clear signs of degradation and slumping at their margins along with a suite of other features that include fractured mounds, polygonal cracks at variable size-scales, and knobby/hummocky textures. Together, these features suggest an ice-rich composition for at least the upper layers of the terrain, which is currently being heavily modified through loss of ice and intense weathering, possibly by wind.

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Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on January 16, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Because an electronic unit for one of this camera’s filters has failed, causing a blank strip in the image center, I have filled in that gap using an MRO context camera image taken October 31, 2015.

The scientists describe this geology as “ridged terrain.” What I see is a surface that was like wet plaster once, and then a giant finger touched it and pulled away quickly, so that as it left some material pulled upward to create random ridges within the depression created by that finger.

These ridges are inside a very very ancient 110-mile-wide crater dubbed Margulis. According to the 2021 poster [pdf] of the scientists who did the first geological mapping of this crater, the crater floor “show remnants of sedimentary materials, suggesting the [crater was] subjected to widespread episodes of resurfacing and denudation.”

Though located in the dry equatorial regions, this ridged terrain suggests it formed suddenly when underground ice sublimated into gas, bursting upward to break the surface when the gas pressure became high enough.
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In preparing today’s cool image I initially planned to post an picture taken on December 26, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), as it showed a strange series of ridges that almost resembled waves or ripples on a pond.

In digging into MRO’s context camera archive to get the larger context, however, I immediately switched to the photo on the right, cropped, reduced, and sharpened to post here. Taken on December 17, 2010, it shows a much more mysterious and striking set of geological features than the closer view of the high resolution image, with the wave-shaped ridges on its western half but another set of wave-shaped cracks on its eastern half.

Even more intriguing, the arcs for the ridges curve in the opposite direction from the arcs for the cracks. It is almost as if there were two flows moving in opposite directions, right next to each other.
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Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on January 12, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Because of a technical issue that leaves a blank strip down the center of recent high-res MRO images, I have filled in that gap using a MRO context camera photo taken on January 12, 2015. The resolution is much less, but by doing so we can see the ground features as a unit.

What are we looking at? According to the scientists, this picture shows “fresh-looking ruptures,” referring to the broken line of sharp tears inside that meandering canyon that almost resemble a fresh wound in flesh. As this location is at 28 degrees south latitude, it lies on the edge of dry equatorial regions, where orbital images have sometimes found hints of a few remaining buried glaciers that are much more common closer to the poles.

In this case it appears the warmer equatorial climate has acted to heat up the buried ice so that it sublimated into gas. At some point the gas pressure caused the surface to burst, much like bubbles bursting on the surface of a pot of simmering tomato sauce, leaving behind these scars.
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Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on January 29, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Though the scientists label this image showing “channels”, what I see is either a vent or a sink, with the channels to the south indicating past flows either coming out of the depression or into it. The uncertainty exists because the surface grade in this region is essentially flat. There is a lot of small up and down variations, but overall it is very difficult to determine the general trend, suggesting that when the depression and channels formed the grade was different, and there is no way from this data to determine the angle at that time.

Were the flows that created the channels lava or water or ice? Knowing the grade when these channels formed would help answer this question, but other research now suggests the latter.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 1, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small part of a region dubbed Iani Chaos, but what this geology shows is way beyond my pay grade.

Why there are those tiny aligned mounds, oriented at right angles to the slope, is not clear at all. Nor is it obvious what created the lighter chaotic terrain at the base of the slope.

The elevation difference between the low and high points is about 400 feet. The slope continues up to the west for another 600 feet to the top of a north-south ridgeline. The patterns here suggest vaguely some flows downhill, such as that widening east-to-west gap, but only vaguely.

The look at the overview map only compounds the mystery.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 31, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled “Lava Embaying Highlands Ridge”, it shows an alcove along a ridgeline that appears filled with material, in this case solid lava.

If you look closely at the ridgeline, you can see several dark streaks on its southern slopes. These streaks could be one of two unique Martian features that remain unexplained. They could be slope streaks, which occur randomly through the year and fade with time, or recurring slope lineae, which occur seasonally at the same locations. In either case, though the streaks look like avalanches, they don’t change the topography, have no debris piles at their base, and even sometimes flow uphill for short lengths. Though there are a number of theories for their formation, many involving dust, none has been accepted as confirmed.

This location and its lava however are the stars of this picture, for a number of reasons, all revealed by 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 December 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The white dot on the overview map above marks the location, with the rectangle in the inset marking the area covered by the picture. The science team labels this “inverted features,” a more vague way to describe the feature geologists dub “inverted channels.” The flow of a river or glacier acts to harden and increase the density of the channel bed. Later, the water or ice disappears, leaving just the canyon.

Even later, erosion begins to wear away the surrounding terrain. Because the canyon floor is now harder than that surrounding terrain, that floor is more resistent to erosion, and eventually becomes ridge following the exact same path as the long gone river or glacier.

This is what we have here, with this inverted channel, which is about five miles long, once draining into the deeper eroded valley to the south.

The location is at 38 degrees north latitude and inside the 2,000-mile-long mid-latitude region I dub glacier country, because almost every image shows evidence of glaciers or ice flows on the surface. This picture however is a rare exception. The features in this picture instead appear to be bedrock, something that is rarely seen in the canyons and craters in glacier country. It is beyond my pay grade however to explain why this spot lacks such features. Or it could be the near surface ice here looks so much like bedrock I am misinterpreting the picture.

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Cool image time! The picture to the right, cropped to post here, was taken on January 24, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a region about 180 miles from the south pole of Mars.

This terrain is intriguing because is the pattern of ridges that cover it entirely. I have simply cropped the original image to show these ridges in highest resolution. The full image shows them covering a region much larger than this.

What are we looking at? Because it is near the pole, it is likely that the black splotches are caused by carbon dioxide gas breaking through the winter mantle of dry ice that covers the poles during the winter months and then sublimates away, from the bottom, each spring. As the dry ice turns to CO2 gas that gas is trapped, until it can find a weak spot in the overlying mantle. When the pressure builds enough, the mantle breaks, the gas escapes, and as it does so it deposits the dark dust around the breakage. That dust fades as the mantle disappears.

Sounds good, eh? Not so fast.
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