Tag: Mars Reconnaissance Orbiter

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Cool image time! The photo to the right, cropped and reduced to post here, was taken on July 24, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a “viscous flow” that has apparently carved the wide curving canyon as it slowly flows into open country to the south.

I would estimate the height of that canyon wall to be around 3,000 feet, though this is a very rough guess. I also image a trail switchbacking up the nose of that canyon wall would make for a truly stupendous hiking experience.

The flow filling the canyon floor appears very glacial, which is not surprising as this canyon is at 37 degrees north latitude, in the mid-latitude band where many glacial features are found. The overview map below provides some more detailed context.
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Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on June 15, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a crater whose ejecta has been sculpted to the east into a teardrop-shaped mesa by some ancient flow, coming from the west.

The crater itself is located in one of several outflow canyons draining out from the volcanic Tharsis Bulge into the northern lowland plain of Chryse Planitia, the biggest of which is Valles Marineris. This particular canyon is one of the smaller and is dubbed Ravi Vallis.

The overview map below illustrates why many scientists think the flow that shaped this mesa came from a catastrophic flood of liquid water, billions of years ago.
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Cool image time! The photo to the left, rotated, cropped, and reduced to post here, was taken on June 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the rim edge to a fifteen-mile-wide canyon, with many apparent layers exposed on the high plateau.

The layers are intriguing in that they suggest several things. First, they give us a glimpse into the top and youngest layers that make up the interior canyon wall. Second, they tell us that erosion has removed much of those top and youngest layers, resulting in the mesas on that plateau.

Finally, the gullies flowing down into the canyon indicate further erosion processes, eating away at the canyon wall over time.

The location of this canyon is also intriguing.
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Cool image time! The photo to the right, rotated and cropped to post here, was taken on June 17, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The section highlighted is at full resolution, in order to make clear the absolutely crazy and complex terrain seen in the full image.

This terrain is not glacial, as the location is only about 1 degree south of the Martian equator. There might have been surface or near surface ice here once in the past, but there is none now.

Could we be looking at some form of lava flow? This is possible, because a close look at the context map at the image link suggests this region has been partly covered by some material, obscuring some craters to the east and west. However, there is no visible evidence anywhere in this region of a volcanic vent or caldera. If this covering material was volcanic it is very unclear where it came from.

The overview map below does not really provide any answers, but at least gives the context.
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Cool image time! The photo above, rotated, cropped, and reduced to post here, was taken on May 13, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows two dramatic ancient flows of flood lava. The arrows indicate what I think is the direction of flow for each, though the direction of the flow to the north appears more certain. In a wider context camera image the bulk of the evidence suggests the southern flow is heading west (as indicated by the arrow), but there are scalloped mesas within it that suggest the opposite.

The overview map above marks the location of this picture by the white cross inside the Athabasca Valles flood lava, thought by some scientists [pdf] to be Mars’ youngest major lava event that erupted about 600 million years ago and in just a matter of a few weeks poured out enough lava to cover an area about the size of Great Britain.

The general trend of the Athabasca flow was to the south, splitting into a big western and southeastern flows. This picture captures the southern edge of that southeastern flow, which might help explain why the flow directions in the picture seem so different from the main Athabasca flow. On a large scale, the flow was to the southeast. On a small scale at the edges the flow could go in many directions as the lava looks to find its level.

The Medusa Fossae Formation is the largest volcanic ash deposit on Mars, and is thought to be the source of most of the red planet’s dust. Though the origin of the ash is not yet known, it likely came from the eruptions that formed the planet’s giant volcanoes to the east and west.

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Today’s cool image provides further proof that there is ample near surface ice almost anywhere on Mars once you get above 30 degrees latitude, in either the northern or southern hemispheres. The photo to the right, rotated, cropped, reduced, and annotated to post here, was taken on May 26, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the interior slope of an unnamed 15-mile-wide crater that sits inside the much larger 185-mile-wide Newton crater, located in the cratered southern highlands of Mars.

The black cross on the global map of Mars above marks the location of this crater.

The photo was taken as part of the routine monitoring planetary scientists are doing of the gullies that flow down this crater’s interior rim, a monitoring program that goes back to 2007. It is thought that those gullies might be created by seasonal frost, either water ice or dry ice, that causes erosion.

What struck me about the photo however was the glacial features on the floor of the crater. Near the bottom of the interior slope those features look broken up, as if the pressure from above pushed the ice sheets apart. Farther from the interior slope the features more resemble a typical glacial flow, slowly inching downward toward the crater’s low spot. All these glacial features also lend weight to the theory that water ice somehow caused or contributed to the formation of those gullies.

The global map above shows that this crater, while well within the 30 to 60 degrees mid-latitude band where many Martian glaciers are found, is also far from the many regions on Mars that scientists have mapped as having high concentrations of glaciers. And yet, the glacial features are here as well.

Near surface ice will not be found at every spot on Mars. However, once you get above 30 degrees latitude, the evidence increasingly suggests that you won’t have to go far or dig down deep to find it.

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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on April 21, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) of a spot in the Martian northern lowland plains.

Generally the surface of these lowland plains — especially at high latitudes above 30 degrees — tends to appear very water saturated, producing blobby features and what look like mud volcanoes. This picture however features something different, what the scientists have labeled fractures, geological features that appeared caused by dry conditions and sudden quake-like events. The break in the fracture near the top of the photo illustrates why water flow had little if anything to do with its formation. Other fractures in the full image show the same thing. Also the stippled surface along the picture’s right edge also suggest there is little near surface water or ice at this location.

The location, as shown by the overview map below, suggests that water might still have played a part, but only a long time ago.
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Today’s cool image once again illustrates how Mars is far from a waterless planet. Instead, there is strong evidence that water ice can be found across most of the Red Planet’s surface, excluding the equatorial regions lower than 30 degrees latitude.

The photo to the right was taken on September 11, 2021 by the wide view context camera on Mars Reconnaissance Orbiter (MRO). It shows a 6-mile-wide unnamed crater on Mars, located at 35 degrees south latitude, with what appears to be a glacier in its interior, flowing to the southwest towards several breaches in the crater’s southwest rim. Several of those breaches now sit higher than the flow, suggesting that the glacier itself was once higher and flowed out of those gaps. Now the level has dropped, and the only place the glacier exits the crater is the central gap at the center of the white rectangle.

That white rectangle marks the area covered by a recent MRO high resolution image, taken on March 29, 2022 and cropped and reduced to post below.
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Today’s cool image to the right, rotated, cropped, and reduced to post here, is actually an older captioned image, published in 2017 by the science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO). I missed its significance when it was first released. From the caption by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

The material on the floor of this crater appears to have flowed like ice, and contains pits that might result from sublimation of subsurface ice. The surface is entirely dust-covered today. There probably was ice here sometime in the past, but could it persist at some depth?

This crater is at latitude 26 degrees north, and near-surface ice at this latitude (rather than further toward one of the poles) could be a valuable resource for future human exploration.

As shown in the global map of Mars above, this 26-mile-wide unnamed crater, marked by the black cross, is well inside the equatorial region 30 degrees north and south from the equator where almost no evidence of near surface ice has been found. Whenever I look at an image from MRO, if the picture appears to show ice or glacial features, its latitude is always 30 degrees or higher. If it does not, it is almost always in this equatorial region.

This crater however shows evidence of glacial features in its interior, but is far closer to the equator than normal. How could this be? It is possible that its high altitude, sitting in the southern cratered highlands, might have helped preserve its buried but near surface glacial features.

Regardless, as McEwen notes, its location closer to the equator is tantalizing, because it suggests that such ice could exist even in the equatorial regions, though buried and thus not detected by the instruments presently available in Mars orbit.

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Cool image time! On Mars it is not unusual to see what scientists call tadpole features, craters with meandering canyons or channels either flowing into or out from the crater’s rim. The photo to the right, rotated, cropped, and reduced to post here, is another example, though with one major difference. The channel and crater are inverted, with the channel instead a ridge and the crater a circular plateau. The picture itself was taken on April 16, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Orbital images have found on Mars a lot of what scientists call pedestal craters, where the impact packed and hardened the ground under the crater so that when the surrounding terrain eroded away the crater remained, as a plateau.

Scientists have also found on Mars a lot of what they call “inverted channels,” places where the channels of a drainage pattern followed the same geological process, becoming more resistant to erosion so that over time it turned from a channel to a ridge.

Here we have a combination of both. The overview map below provides us the larger picture.
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