Tag: Mars

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows what appears to be a glacial flow of ice, flowing downhill to the southwest and inside a wide canyon about three miles across. The canyon rims to the north and south are about 2,000 to 2,100 feet above the canyon’s lowest point, indicated by the string of “+” signs.

This close-up view immediately suggests a canyon whose glacier flows outward to the southwest into open lowland terrain, though the three craters, because they are undistorted, suggests that this flow is presently not active. That suggestion however would be wrong. It is always necessary to understand Martian geology to not only take close-in views at high resolution, but to zoom back and see the terrain in context.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 4, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled a “terrain sample” by the science team, it was likely shot not as part of any specific research project but to fill a gap in the schedule so as to maintain the camera’s proper temperature. When the camera team has to do this they try to pick targets that are of some interest. Usually they succeed, considering the enormous gaps we presently have of Mars’ geological history.

This picture is no different. It shows a land of buttes and mesas, all ranging from 20 to 200 feet high, surrounded by canyons filled with ripple dunes of Martian dust. If you look at the floor of those canyons closely, you will notice that where there are no ripple dunes the ground is slightly higher and smooth. It is as if that ground was a kind of sandstone that was eroded away by wind into sand, which then formed the dunes.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 6, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the steep north canyon wall of one small part of the Martian canyon complex dubbed Noctis Labyrinthus

The elevation drop in this picture is about 8,000 feet, but the canyon’s lowest point is several miles further south and another 7,000 feet lower down. What is most intriguing about the geology here is its age. If you look at the full resolution image, you will see that there are scattered small craters on the smooth slopes that resemble sand that gravity and wind is shaping into those long streaks heading downhill.

Those craters, however tell us that these smooth slopes are very old, and have not changed in a long time. Furthermore, though the material appears to look like soft sand, the craters also tell us it long ago hardened into a kind of rock. If wind is shaping this material, it must be a very slow process.

The light areas on the rim as well as the ridge peaks below the rim suggest the presence of geological variety, which fits with other data that says Noctis Labyrinthus has a wide variety of minerals.
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Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on August 14, 2023 by the high resolution camera on Mars Reconnaissance Orbiter. It shows the cracked top of a enscarpment, with the bottom point to the west about 2,400 feet lower in elevation.

The north-south cracks at the top of the cliff indicate faults. They also suggest that the cliff itself its slowly separating from eastern plateau. North from this point, beyond the edge of this picture, are several places where such a separation has already occurred, with the collapsed cliff leaving a wide pile of landslide debris at the base.

This cliff actually continues north for another 400 miles, suggesting that the ground shifted along this entire distance, with the ground to the east going up and ground to the west going down. Because the cliff is such a distinct and large feature, it has its own name, Claritas Rupes, “rupes” being the Latin word for cliff.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 18, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists only call this a “feature,” likely because they don’t wish to guess as to its nature without more data. However, the 2.5 mile wide splash apron around the central double crater certainly merits a closer look. That double crater could be from impact, but it also could be a caldera, with the apron the result of material that flowed from the caldera.

That there appear to be fewer craters on the apron than on the surrounding terrain strengthens this last hypothesis. The apron would have erased many earlier impact craters, resulting in this lower count.

The location however suggests that if this feature was volcanic in origin it might not have been spewing out magma.
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Cool image time from Mars! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 13, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It highlights a string of craters, all lined up in an almost straight line.

Were these craters caused by the impact of an asteroid that broke up as it burned its way through the thin Martian atmosphere? The lack of any raised rims argues instead that these are sinks produced not from impact but from a collapse into a void below, possibly a fault line.

Yet, almost all of the craters in this image, even those not part of this crater string, show no raised rims. If sinks, the voids below don’t seem to follow any pattern, which once again argues in favor of random impacts, with the string produced by a bolide breaking up just prior to hitting the ground.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 18, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists dub as “large gullies with infilled alcoves.”

Gullies on Mars were one of the first discoveries by orbiters of small-scalle potential water-caused features on the Red Planet. The favorite explanation for their formation today involves the seasonal freeze-thaw cycle, combined with the deposition of ice and dry ice frost in the winter. When that ice and dry ice sublimates away in the spring it causes collapse and erosion, widening the gullies.

These gullies also exhibit evidence that underground and glacial ice might contribute as well. The material in the largest gullies looks like a mixture of glacial material and dust and debris. It could also be that there is ice impregnated in the ground, which can cause large collapses when it sublimates away.

The white rectangle on the overview map and inset above marks the location of this picture, on the western rim of a 13-mile-wide unnamed crater inside the western portion of the 2,000-mile-long mid-latitude strip on Mars I dub glacier country, since every image from orbit shows evidence of glaciers.

This picture is no different, as the horizontal cracks at the base of the crater rim suggests the glacier that fills the crater floor is being pulled apart by gravity at its edges. The elevation drop from the top of the rim to the floor is about 3,200 feet, so any ice on that slope will definitely be stressed by gravity. Such cracks are therefore not surprising.

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 10, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the northeast corner of an unnamed 7-mile-wide crater, located near the equator in the dry Martian tropics.

The MRO science team labels this “crater and lava fill”, suggesting that the crater interior is filled with lava material. The nature of that crater floor reinforces this conclusion, as it is relatively smooth and does not have rough aspects of glacial material found in craters in the mid-latitudes. Instead, it looks like a frozen lake of lava that has the peaks of mostly buried features poking up at various spots.

What makes this crater interesting however are the gullies on the northern interior rim. Gullies on Mars are normally thought to be associated with some water-frost-ice process, probably seasonal, where the thaw-freeze cycle causes small collapses and avalanches. Yet, this crater is almost at the equator, in a very dry region where no evidence of near-surface ice is found. Gullies here suggest the hypothesis for explaining the gullies on Mars have not quite solved 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 June 27, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small section of the floor and northern slope of Hebes Chasma, one of the many very large enclosed pits that can be found to the north of Valles Marineris, the largest canyon in the solar system. Though Hebes seems small next to the 1,500 mile long Valles Marineris, it still is 200 miles long by 80 miles wide, and could easily fit a half dozen Grand Canyons within it.

For example, the Grand Canyon is from 4,420 to 5,400 feet deep, hiking down from the south and north rim lodges respectively, which sit about ten miles apart. On this picture, the peak on the right sits about 5,300 feet above and only about 3.8 miles from the low spot on the bottom left, which means this one small picture encapsulates the Grand Canyon. And yet, the northern rim of Hebes sits another 21,000 feet higher and twelve miles away. And the entire chasma itself extends 50 miles to the west, 150 miles to the east, and 50 miles to the south.
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Today’s cool image will be a mystery with the answer below the fold. Before you look at the answer, however, you must try to come up with your own explanation for the picture to the right, cropped to post here, that was taken on September 25, 2018 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

What we see in this picture is what looks like a striped terrain, alternating bands of light and dark. What caused the bands? Why the different colors?

The overview map above provides some clues. The white rectangle inside Juventae Chasma near the map’s center marks the area within which this picture was taken, though the picture to the right covers only about a pixel inside that rectangle.

Can you guess what these stripes reveal, from this little information? For this quiz to work you must make a guess, but be prepared to be wrong and quickly reassess your conclusions. Such is the real scientific method, so rarely taught now in schools.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 19, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The features are described as “ribbed terrain” in the label. To my eye they more resemble flakes of peeling paint, most especially the mesas in the lower left. On the full image there are many more examples that resemble old paint peels, barely attached to the wall.

The white dot on the overview map above marks the location, deep inside the 2,000-mile-long strip in the northern mid-latitudes I dub glacier country, because everything seems covered by glacial features. This location is at 42 degrees north latitude, where plenty of near-surface ice features are found on Mars.

At first glance it looks like the top “paint-peel” layers to the south have been slowly sublimating away, leaving behind the smooth plain to the north. The problem is that this smooth area in the full image actually appears to be a glacial ice sheet of its own, filling all the low areas between mesas.

In other words, we are probably looking at layers and layers of ice sheets, each created during a different Martian climate cycle, caused by the wide swings of the planet’s rotational tilt, or obliquity.

The location is within Arabia Terra, the largest transitional zone on Mars between the northern lowland plains and the southern cratered highlands. Thus it sits above the glaciers that fill the lower regions of chaos to the north. What we have here is terrain that will eventually become chaos terrain, as the narrow faults and cracks are slowly widened into canyons by the cycles of glacial activity.

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

The picture label describes it as a “Low Shield Vent and Pit Northeast of Arsia Mons,” suggesting these depressions are volcanic in nature. We know the pit in the lower left is not an impact crater because it has no raised rim of ejecta. Instead, it looks like a collapsed sinkhole, formed when the ceiling above a void could no longer support its weight. Similar, the trench to the northeast is aligned with the downhill grade to the northeast, with its features suggesting a vent draining in that direction.

The ample dust inside the trench and pit suggest that it has been a very long time since this vent was active. Research suggests volcanic activity last occurred in this region from 10 to 300 million years ago, so that gives us a rough estimate of this vent’s age. Since then any dust that is blown into it will tend to become trapped there.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 1, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled by the science team as showing “possible lava-ice interaction,” the photo features some pimply-looking mounds that, though round like craters, sit above the surrounding landscape like small volcanoes.

That these are likely not ancient pedestal impact craters that now sit higher because their material is packed and can resist erosion is illustrated by the bridge-like mound in the lower right. This mound was likely once solid, but its north and south sections have disappeared, either by erosion or sublimation. If formed by an impact the mound would have had a depression in its top center, and would have only eroded outside the rim.
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Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on June 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the top half of the northwestern interior wall of the central caldera of Pavonis Mons, the center volcano in the string of three giant volcanos found in Mars’ equatorial regions.

The elevation change from the top to the bottom of this picture is about 7,000 feet, though this covers only half the distance down to the floor of the caldera. The picture was taken as part of a survey of this caldera wall.

Volcanic activity here is thought to have ended more than a billion years ago. Thus we are looking at relatively old terrain that has had many eons to be reshaped since the last eruption.
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Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on August 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have also inserted data from a July 28, 2008 context camera image into the blank strip that now exists in the center of high resolution camera images due to the failure of one sensor.

This photo is what the camera team calls a terrain sample, and was probably taken not as part of any specific request but to fill a gap in the camera’s schedule in order to maintain its proper temperature. When the camera team does this they try to find locations that either have not been observed in much detail previously or have interesting features. In this case the team accomplished both. The interesting features are the two pedestal craters, both surrounded by splash aprons. Neither has been observed in high resolution previously, and the context camera has only taken two pictures of this location in total.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 21, 2023 by the high resolution camera on Mars Reconnaissence Orbiter (MRO). Its focus is the meandering ridge in the center of the picture, which the scientists intentially describe vaguely as a “ridged flow-like feature”.

The elevation difference between the high and low points within the picture is about 500 feet, though most of that slope occurs in the lighter terrain on the right. The darker area where the ridge is located has no clear elevation trend, though there are hints of depressions and rises within it.

The yellow dot on the overview map above marks this location, deep within the chaos terrain dubbed Deuteronilus Mensae, on the western end of the 2,000 long northern mid-latitude strip I dub glacier country, because practially every image from there shows glacial features.

To underline this fact, the red and white dots mark previous cool images from 2020 and 2021, with the first showing an eroded glacier and the second glacial ice sheets.

The mesa to the east of this picture rises more than 6,000 feet to its peak, as indicated by the black dot. This is also the highest point for this entire grouping of mesas. All are surrounded by a single large apron of material, likely a mixture of alluvial fill and ice.

What however caused the narrow ridge in the picture above? Is it ice or bedrock? If ice why is it so different than the glacial material that seems to surround it? If bedrock, it suggests it is instead an ancient inverted channel created when that ridge was a canyon through which ice or water flowed, compacting the canyon floor. When the terrain around it eroded away it was more resistent and became a ridge instead.

I have no answer. The colors suggest the ridge is rock, not ice, but that is not conclusive.