Tag: Mars

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 30, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is labeled as a “terrain sample,” so it was likely taken not as part of any specific research project but to fill a gap in the camera’s schedule.

The subject this time was a series of parallel ridges. I have cropped the image to focus on the most distinct, which stands at its highest about 600 feet below the dune-filled hollows to the north and south. The streaks on its flanks are likely slope streaks, a phenomenon unique to Mars that is presently not entirely understood. Streaks appear like avalanches, but they do not change the topography at all, and in fact in some cases go up and over rises. It is believed they are related to dust events, but this is not yet confirmed.

Why focus on this ridge however? It isn’t as if this is the most stunning geology on Mars.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 31, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as 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 in order to maintain its proper operating temperature.

In this case the camera team picked a spot in the northern lowland plains at 39 degrees north latitude. What they got was another great piece of evidence of the existence of a lot of near surface ice on Mars, so much so at this location that the craters have become distorted and blobby. The ice in the ground is unstable enough that nothing here can really hold its shape from season to season and from decade to decade.

As I have noted repeatedly in the past six years, MRO data is proving that Mars is not a dry desert like the Sahara, but an icy desert like Antarctica. Except for the planet’s dry tropics below 30 degrees latitude, Mars appears to have a lot of frozen water available relatively near the surface.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on July 29, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the northeast quadrant of a weirdly distorted unnamed 3-mile-wide crater in the northern lowland plains of Mars. The crater rim is the ridgeline that enters from picture’s left edge to curve down to exit at bottom right.

The geological feature of interest however is the strange mound to the left of that rim, inside the crater. It certainly appears, based on shadows, that the top of this mound popped off at some time in the past, leaving behind that sharp-edged hollow.

Note however that there is no eruption debris. When a volcano erupts, the debris covers the nearby mountainside. Here we see no evidence of anything that was flung out from this small eruption.
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Cool image time! The picture to the right, cropped and color-enhanced to post here, was taken on November 3, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The picture is labeled as a “terrain sample,” which means it was likely taken not as part of any specific research project, but to fill a gap in the camera schedule in order to maintain the camera’s proper temperature. In this case the camera team tries to choose interesting features, though sometimes they can’t due to timing.

In this case they were able to target a nice piece of geology, a layered 2,000 foot cliff on the outer edge of the south pole ice cap. The color strip illustrates the possibilities within those layers. I have significantly enhanced the colors to bring out the differences. The orange suggests dust, the aqua-blue water ice, though these colors could also indicate interesting mineralogies.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 27, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The red dot on the overview map above marks the location, about 35 miles southwest of the rim of 80-mile-wide Moreau Crater. This location is also deep within the 2,000-mile-long northern mid-latitude strip I label glacier country, as almost every high resolution picture from MRO shows glacial features.

This picture is no different, in that it shows the typical lineated parallel grooves seen on the surface of glaciers both on Earth and Mars, and especially found on glaciers flowing within a narrow canyon, as this glacier is. The parallel grooves are caused by the waxing and waning of the glacier. Each layer represents a past period when ice was being deposited on the surface, with the grooves indicates times when that ice was sublimating away. The graceful curves of the grooves is due to the drift of the glacier itself downhill.

This canyon is about seven miles wide at this point, formed from the confluence of two southerly tributaries to the south. The downward grade is to the north, but the low point is not where you would expect, out into the northern lowland plains. Instead, I have marked the low point in the inset with a white dot, inside the canyon itself. It appears this glacier drains into this low spot, but then this debris-covered ice appears to vanish.

It can’t really vanish, but there is a geological mystery here that involves the alien nature of Mars. For some reason the glacier dies at this point, its material sublimating away. Is there a drainage here that sends the ice to the north by underground passages? Your guess is as good as mine.

The lineated nature of this glacial flow however is no mystery in one respect. It is quite beautiful, as seen from space.

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this “layered rock.” I label it another one of my “What the heck is that?” images on Mars. If I didn’t know this was an orbital image looking down at an alien planet, I’d think it was a paisley pattern on a piece of dark fabric.

The converging “streams” suggest flows, but there really is no clear downhill grade, the landscape generally flat. The lighter patches suggest either higher terrain the flows went around, or places where something bubbled up from below. Or maybe the “flows” are actually cracks that the bubbling material filled as it rose.

I have no idea if any of these theories is right.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 24, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have also rotated the image so that north is to the top.

The scientists label this a “dune with seasonally persistent light-toned features.” As the location is in the high southern latitudes, only about 800 miles from the south pole, light-toned features should vary by seasons, as such features usually signal the coming and going of frost, whether it be water ice or dry ice. In this case however the light tones remain from season to season, which suggests the lighter colors are intrinsic to the ground and possibly signal some interesting geology or mineralogy.

The color strip down the center of the dune is an effort to decipher this question. According to the explanation about the colors [pdf] provided by the science team, the orange and light green probably indicates fine dust, while the greenish area along the ridge’s rim as well as its eastern slope suggests frost. Thus, based on the superficial information available to the public, the colors tell us little.
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Today’s cool image to the right demonstrates that the atmosphere and climate of Mars is truly different in different places. The picture, rotated, cropped, reduced, and sharpened to post here, was taken on July 22, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample”, it was likely taken not as part of any specific research project but to fill a gap in the camera’s schedule in order to maintain its proper temperature.

I post it today almost to illustrate the difference between this location and the spot where the lander Insight landed on Mars. Earlier this week the MRO camera team released a short movie created by images of the lander taken over six years, showing how the dust around it had changed over time. I noted further how those images showed a very small number of dust devil tracks, which explained why no dust devil every crossed over the lander’s solar panels to clean them of dust.

For the picture on the right, however, there are a lot of dust devil tracks, so many near the bottom that they almost completely darken the ground.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 17, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely taken not as part of any specific research project, 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 pick interesting targets. In this case, they targeted this 400-foot-high pointy-topped hill. The smoothness of its slopes suggest this hill is made up largely of packed dust, possibly a hardened former dune. This hypothesis seems strengthened by the erosion on the eastern slopes, which appears to be areas where that packed sand has worn or blow away.

Think of sandstone in the American southwest. It is made of sand that has hardened into rock, but wind and water and friction can easily break it back into dust particles, resulting often in the spectacular and weird geological shapes that make the southwest so enticing.

But is this sand?
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 25, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the camera team labels as a “mound in the southern highlands.”

The mound in question sits in the center of the sunken depression, and at the highest resolution shows its top to be cracked and broken, as if something is attempting to break out by pushing up from below.

Everything about this picture screams near-surface ice. The cracked mound suggests ice sublimating into gas, which applies pressure to the surface and thus the cracks. The depression suggest that much of the near-surface ice at this location has already disappeared, causing the ground to sag. All the craters lack upraised rims. If caused by impacts, the ground here was soft enough that the impactor simply sank into the ground. Imagine dropping a rock you’ve heated into snow. It would simply leave a hole.

But there’s more. The white dot in the overview map above marks the location. In the inset, the lighter area surrounding this depression resembles an ice sheet that is slowly sublimating away. There are also other similar depressions in that lighter area. The lighter area also has fewer craters than the darker regions nearby, suggesting that this ice sheet covers the older impacts.

The location is in the southern cratered highlands in a mid-latitude region where many images indicate the existence of layers of ice deep below ground. This picture is more evidence of the same, but it also indicates the presence of ice very close to the surface as well.

The orbital data continues to tell us that Mars is not a dry desert like the Sahara, but an icy desert like Antarctica. There will be plenty of water for future colonists. All they will have to do is stick a shovel in the ground, dig it up, and process it.

Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on July 16, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what MRO’s camera team labels as “layers near ridge in Argyre Planitia.”

The layers are strange because there is so little topographic difference between them. Though the ground slopes downward from the south to the north, dropping about 1,300 feet, it does so almost smoothly. The layers show relatively little topographic relief.

And what caused the circular shape? Is it evidence of a buried crater? And if so, why so little relief at its rim?

As always, the overview map provides some answers.
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Today’s cool image will be unlike most cool images, in that we will begin not with the image but with the overview map to the right. The long meandering canyon at the center of this map is Nirgal Vallis, a 300-mile long canyon on Mars that eventually drains to the east into a much larger drainage system that runs south-to-north several thousand miles into the Martian northern lowland plains.

At first glance Nirgal Vallis invokes a river system. It starts in the west as several branches that combine to form a single major canyon meandering eastward until it enters that south-to-north system. To our Earth eyes, this canyon suggests it was carved by water flowing eastward, the many drainage routes combining as they flowed downhill.

Today’s the cool image, its location indicated by the white dot, tells us however that liquid water might not have been what created this canyon.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 2, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The white dot in the overview map above marks the location, inside the chaos terrain of Deuternilus Mensae and part of the 2,000-mile-long mid-latitude Martian strip I label “glacier country,” because practically every image of every part of its landscape has glacial features. For example, the splash apron around the picture’s largest crater as well as the material within it all suggest some form of glacial activity and near-surface ice.

The scientists label what they see here as “Mesas in Small Craters.” These features are located in a low flat plain that geologists think was created when the ground eroded away, leaving behind scattered high plateaus that indicate the previous surface elevation. The geological map [pdf] of this plain describes it as follows:

Smooth, relatively featureless materials with regions of variable albedo north of continuous cratered highlands; exhibits scattered clusters of small circular to irregular knobs.

Based on the many accumulated photos from MRO, the general conclusion is that we are looking at a sheet of ice/dirt and covered by a thin dust layer that acts to protect that ice from sublimating away. When wind blows that dust off and the summer sun hits that near-surface ice, however, it does sublimate in bursts, which thus provides an explanation for the erosion that caused these low featureless plains.

As for these strange terraced mesas inside these distorted hollows, my guess is that the mesas predate the icesheet and are made of material with less ice impregnated within it. As that ice sublimates away it creates the craters within which the mesas remain. The terraces suggest a earlier series of geological sedimentary history.

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 27, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The picture was simply labeled a “terrain sample,” which usually means it was taken not as part of any specific research request, but to fill a gap in the schedule so as to maintain the camera’s proper temperature. When such gap-filler pictures are necessary, the MRO camera team tries to snap something of interest. Sometimes the pictures end up somewhat boring. This time however the picture highlights a dune field that is unusually light in color.

Since most Martian sand is volcanic in origin, it tends to look dark in orbital pictures. That this sand looks bright could be because it is inherently different, or it could be that lighting conditions make what normally looks dark to look bright instead.
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Today’s cool image is another example of what I call a “What the heck!” image. The picture to the right, simply cropped to post here, was taken on September 22, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows what the scientists label as “etched terrain,” an incredibly twisted and eroded landscape that to me actually defies description. In trying to research what scientists have learned and theorized about this terrain, it appears they think it is material that flowed over older terrain (thus its lack of many craters) that was subsequently eroded by later processes.

Why it eroded so strangely however is not really understood. It could have been caused by near-surface ice sublimated to the surface and thus causing many breaks, but since this terrain is located right on the equator in the dry tropics, it is a very long time since water was present here.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 9, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The white dot on the overview map above marks the location, inside the deep enclosed and very large 130-mile-wide depression dubbed Juventae Chasma.

The mountain in the picture raises above the sand sea that surrounds it from 1,000 to 2,300 feet, depending on direction, as the downhill grade of the sand sea is to the east. Thus, on the west the mountain rises less, while on the east the height is the greatest.

The inset illustrates the extent of the sand sea. It covers the ground for many miles in all directions. The way the sand surrounds these mountains suggests the prevailing winds blow from the west to the east. In fact, the facts suggest that this sand is volcanic ash that was blown into Juventae from many eruptions that occurred over time to the west, where it got trapped. The wind and gravity deposited the sand into the 20,000 to 25,000-foot-deep chasm, where the wind was insufficient to lift it out again.

One wonders how deep that sand sea might be. The lack of any surface features at all suggests it could be quite deep, burying everything but the highest peaks. In fact, if a geologist could drill a core through that sand I suspect he or she might be able to document the entire eruption history of much of Mars.

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 20, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labels the entire picture simply as “gully,” obviously referring to that distinct and somewhat deep hollow in the middle of the picture.

Most gullies that have been found on Mars tend to look more eroded and rougher than this hollow. Here, it appears almost as if the process that caused this gully occurred relatively recently, resulting in its sharp borders that have not had time to crumble into softer shapes.

The crater interior slope is about 1,500 feet high. Whatever flowed down it however did not do it in an entirely expected manner. As it flowed it curved to the west, so that the impingement into the glacial material that fills the crater floor is to the west of the gully itself. Either that, or that impingement was caused by a different event at a different earlier time.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 10, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

My reason to posting this I admit is selfish and tourist-oriented. This narrow ridge, about a mile long and about 300 to 600 feet high, appeals directly to my hiking passions. A trail along its length would provide any hiker some really spectactular views.

The scientists took the picture because of the geology. The white dot on the overview map above marks the location, a short channel dubbed Daga Vallis that connects two major canyons in the eastern part of Valles Marineris, the largest known canyon system in the solar system. This ridge and several nearby parallel ridges were apparently made of something, possibly lava, that was resistent to the theorized ancient catastrophic floods that scientists presently believe carved out these channels and canyons.

In the inset the dotted line indicates one possible hiking trail route that travels the full length of the ridge but then heads south to continue along the rim of a 1,200-foot-high cliff face. For future Martian colonists, I offer this site as a great place to set up a bed-and-breakfast, surrounded by many potential hikes of incredible stark beauty.