Dramatic layers in Valles Marineris

Dramatic layers in Valles Marineris
Click for original image.

Cool image time! The picture to the right, rotated, cropped, and sharpened to post here, was taken on December 28, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows one tiny section of the interior slope of the giant Martian canyon Valles Marineris.

The while layers are not made of frost or ice, because they are light tan, as per the color image. Thus, the alternating layers of dark and light indicate different layering events. The dark layers are probably major lava flood events with a lot of dark ash intermixed, while the tan layers were flood lava events with little dark ash.

The dark lines that cut across these layers are ripple dunes formed from dust that has accumulated inside Valles Marineris.
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Buried silo on Mars?

A buried silo on Mars?
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Cool image time! The picture to the right, rotated and cropped to post here, was taken on December 31, 2022 by the high resolution camera on Mars Reconnaissance Orbiter.

The headline is pure silliness, and should not be taken seriously. However, the geological feature is intriguing nonetheless. Its almost perfect circular shape suggests a partly buried or eroded crater, except that its consistent thickness, almost like a wall, does not match what the rims of any crater should look like. Crater rims are made up of ejected material pushed out during impact, and thus always include some chaotic features.

My guess is that this circular feature is volcanic in nature. Maybe this was once a caldera, and the circle indicates a final vent from which lava extruded and then solidified.

At least, that’s my story.

The feature is located in the southwest quadrant of Hellas Basin, the basement of Mars, at 49 degrees south latitude. While this also suggests that ice might help explain this, we must also remember that much of the geology in that basin remains unexplained. Thus, there is no reason not to add one more feature to the list.

A Martian hill of pillows

Curiosity's future path, taken January 31, 2023
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The cool image above was taken on January 31, 2023 by the left navigation camera on the Mars rover Curiosity. The red dotted line indicates roughly the planned route forward for the rover, though as Curiosity gets closer to that hill the terrain is looking increasingly difficult. The white box in the panorama below, taken two weeks earlier when the rover was about five hundred feet away, indicates the area covered by this picture. Since then Curiosity has traveled about 200 feet closer.

I post this picture specifically because of the small hill to the right of that path. Probably no more than fifty feet high, its entire surface appears cloaked by a pile of large, pillow-like pavement stones, almost as if the ground below had been washed away so that the massive top layer fell downward over time. Later, wind erosion over eons smoothed the rough edges of those massive blocks, giving them their cushion-like shapes.

This is strange geology. You might see such strange geology on Earth, but rarely. On Mars however strange geology appears increasingly common.

Moreover, to get a 3D sense of this terrain, load into your browser (on separate tabs) the full images of this hill, taken by Curiosity’s right and left navigation cameras (here and here). If you switch back and forth quickly between those tabs, you will see the slight shift in position between the two cameras, and be able to perceive this hill in three dimensions.

Panorama taken January 17, 2023 by Curiosity

Ingenuity successfully completes 41st flight

Overview map
Click for interactive map.

On January 27, 2023, the Mars helicopter Ingenuity successfully completed its 41st flight, flying about 600 feet total in an out-and-back flight that took 109 seconds, slightly longer in length and time than originally planned.

You can watch a very short animation from a handful of the pictures taken during the flight at the first link above. The green dot on the overview map to the right marks Ingenuity’s position before and after the flight, the blue dot Perseverance’s present location. The green line indicates the flight’s approximate path, designed to scout the route that Perseverance intends to follow, as indicated by the red dotted line. The actual flight path has not yet been published. I will add it to this map when the Ingenuity science team provides it.

Expect the next flight to duplicate this one, except it will likely not return but land somewhere out ahead.

That ain’t snow on Mars

That ain't snow on Mars
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Today’s cool image proves once again that you must never too quickly jump to any conclusions when you first look at a picture from space. The photo to the right, cropped, reduced, and sharpened to post here, was taken on November 24, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

At first glance it appears that those ridges are topped with patches of snow or frost. Not. What appears white in this black and white photo is immediately revealed to be light-colored dust in the color image.

According the label assigned to this image by the science team, these ridges represent layers, likely tilted steeply so that when exposed they form the layered cliff edges where that light dust has now gathered.

The overview map below provides further evidence that the white patches are dust, not snow.
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Perseverance completes placement of first ten samples for later pick up

Overview map
Click for interactive map.

On January 29, 2023 the Perseverance science team completed the placement of the first ten core samples on the floor of Jezero Crater.

On the overview map to the right, the green outline indicates the location of this sample depot. The blue dot marks Perseverance’s present location, while the green dot marks Ingenuity. The red dotted line shows the planned route up onto the delta, which is Perseverance’s next goal.

The titanium tubes were deposited on the surface in an intricate zigzag pattern, with each sample about 15 to 50 feet (5 to 15 meters) apart from one another to ensure they could be safely recovered. Adding time to the depot-creation process, the team needed to precisely map the location of each 7-inch-long (18.6-centimeter-long) tube and glove (adapter) combination so that the samples could be found even if covered with dust. The depot is on flat ground near the base of the raised, fan-shaped ancient river delta that formed long ago when a river flowed into a lake there.

This mapping will be used by a future Mars helicopter to precisely land by each sample, grab it, and then take it to the ascent vehicle for return to Earth.

Curiosity looking back

Panorama by Curiosity, looking back
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Overview map
Click for interactive map.

Curiosity is now about halfway across the flat marker band terrain it faced last week, and as part of its routine, used its right navigation camera on January 28, 2023 to create a 360 degree panorama mosaic of the Mount Sharp foothills that now surround it. The panorama above, cropped, reduced, and sharpened to post here, focuses on the part of that mosaic looking behind Curiosity.

You can see the rover’s recent tracks as it crossed this part of the marker band. In the far distance can be seen in the haze the rim of Gale Crater, approximately 20 to 40 miles away. The yellow lines in the overview map to the right show the approximate area covered by this section of the panorama. It is possible the peak of Navarro Mountain is peeking up in the center of this panorama, but more likely it is no longer visible, blocked by the smaller but closer hills.

As Curiosity is now inside the foothills of Mount Sharp, the floor of Gale Crater is no longer easily seen. The rover needs to be at a high lookout point, something that will likely not occur in its travels for many months if not years to come.

The Curiosity pictures I am featuring this morning are cool, and they are also the only real news in the space field at this moment. As is usual on Monday, it takes few hours for the news at the beginning of the week to make itself known.

A cloud on Mars

A cloud on Mars
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Cool image time! The photo to the right, reduced and sharpened to post here, was taken on January 27, 2023 by Curiosity’s high resolution camera (dubbed Mastcam) as part of its periodic survey of the sky, looking for clouds. Most of the time the sky is either hazy or clear. This time the camera picked up this cloud, which resembles a cirrus cloud on Earth.

In March 2021 I posted another example of clouds found above Gale Crater by Curiosity. Two months later the science team released a press release about those clouds, which might help explain the cloud above.

The fine, rippling structures of these clouds are easier to see with images from Curiosity’s black-and-white navigation cameras. But it’s the color images from the rover’s Mast Camera, or Mastcam, that really shine – literally. Viewed just after sunset, their ice crystals catch the fading light, causing them to appear to glow against the darkening sky. These twilight clouds, also known as “noctilucent” (Latin for “night shining”) clouds, grow brighter as they fill with crystals, then darken after the Sun’s position in the sky drops below their altitude. This is just one useful clue scientists use to determine how high they are.

Even more stunning are iridescent, or “mother of pearl” clouds. “If you see a cloud with a shimmery pastel set of colors in it, that’s because the cloud particles are all nearly identical in size,” said Mark Lemmon, an atmospheric scientist with the Space Science Institute in Boulder, Colorado. “That’s usually happening just after the clouds have formed and have all grown at the same rate.”

Though usually formed from water-ice, there is a chance this cloud is formed from crystals of dry ice. More analysis will of course be necessary to make that determination.

Glaciers or taffy on Mars?

Glaciers of taffy on Mars?
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Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on November 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was released on January 4, 2023 as a captioned image, with this caption by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

The floor of the Hellas impact basin, the lowest elevation on Mars, remains poorly explored because haze often blocks it from view. However, we recently got a clear image, revealing the strange banded terrain. These bands may be layers or flow bands or both.

At first glance, these bands reminded me of the many glaciers found on Mars. McEwen however is being properly vague about the nature of these features, for a number of reasons illustrated by the overview map below.
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A Martian bear!

A Martian bear!
Click for original image. Full image here.

Silly image time! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter posted the photo to the right, which I have cropped, reduced, and annotated to post here. It was taken on December 12, 2022, and was rotated so that north is to the right in order to make its resemblance to a bear’s face obvious. As noted in the caption by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

There’s a hill with a V-shaped collapse structure (the nose), two craters (the eyes), and a circular fracture pattern (the head). The circular fracture pattern might be due to the settling of a deposit over a buried impact crater. Maybe the nose is a volcanic or mud vent and the deposit could be lava or mud flows?

Maybe just grin and bear it.

If you have red-green glasses you can see a 3D anaglyph of this image here. The feature itself is located in the southern cratered highlands of Mars at 41 degrees south latitude, so the presence of near surface ice that would cause a mud volcano is definitely possible.

A dry lakebed on Mars?

Evidence of a past lake in a crater on Mars
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Today’s cool image illustrates in some ways the uncertainty of science. The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on December 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team intriguingly labeled it “Small Candidate Lake Deposit Downstream of Alluvial Fan.” I am not sure what they consider that lake deposit in the full image, so I have focused on the area of stucco-like ground, which resembles bedrock that has been corroded by some water process.

This area is just to the east of the central peaks of an unnamed 25-mile-wide crater in the southern cratered highlands. Many of the craters in this region are believed by scientists to have once harbored lakes formed by run-off from the glaciers that once existed on the craters’ inner rim. In this case it appears this stucco area is the head of an alluvial fan, coming down from the crater’s central peaks. You can see its beginning in this MRO high resolution image of the central peaks, taken in November 2016. As defined geologically,

An aluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but are also found in more humid environments subject to intense rainfall and in areas of modern glaciation.

In this case the terrain is now arid, but shows evidence it once was icy wet.
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Curiosity’s drill fails for the fourth time to drill into the marker band layer on Mt Sharp

The fourth attempt yesterday to use Curiosity’s drill to drill into the marker band layer on Mount Sharp once again was unable to drill down deep enough to obtain a sample.

Despite giving it the “old college try,” Curiosity’s attempt to drill into the Marker Band at the “Encanto” site did not reach sampling depth. Because other rocks around the rover look similar to “Encanto” and are likely also too hard to drill, the Science Team decided to convert the plan to a “Touch and Go.”

Although the Science Team is disappointed to leave this Marker Band location without a sample, Curiosity will use MAHLI, APXS, and ChemCam LIBS to analyze the chemistry and texture of the shallow “Encanto” drill hole and tailings, targeting the intriguing light-toned material exposed in the wall of the drill hole. We may see another location in the Marker Band worth sampling in the near future, but even if we don’t, there will certainly be many more exciting drilling opportunities to look forward to as Curiosity continues her climb up Mt. Sharp!

This drilling difficulty is not a surprise. The marker band is a very distinct flat layer that is seen at about the same elevation on all sides of Mount Sharp. It flatness suggests it is resistant to erosion, which also suggests its material will be hard. The inability of Curiosity’s drill to penetrate it only confirms this.

It also makes getting a drill sample to test even more intriguing. I suspect that the science team is going to try a few more times as it travels forward across the band, as indicated by the red dotted line in the panorama below.
Panorama as of January 17, 2023
Click for full image.

Martian crater with mound of ice? mud? hardened sand?

Crater with mound
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Cool image time! The photo to the right, cropped to post here, was taken on October 31, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small 4,000-foot-wide crater that is practically filled with a smooth, almost perfectly spherical mound, with the rest of the crater interior filled with sand dunes and what appears to be glacial debris.

Is that mound also glacial debris, covered with a layer of dirt and dust to protect it? If so, one wonders how the ice ended up in this shape. There are other craters with similar mounds in this region, all suggesting glacial debris but with the same question. Craters with lots of near surface ice in this region more often have a squishy blobby look.

Is the mound instead possibly mud, expressing the existence of a mud/ice volcano? If so, it shows no central pit or caldera, which is typical of such things.

Is it hardened sand? Martian dust that gets blown into craters generally gets trapped there, building up over time. If so, however, why does it have a smooth almost perfectly rounded shape? The ripple sand dunes surrounding it are more like what you would expect.

The small craters on the mound also tell us that it is hardened and old, no matter what it is made of.
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The youngest flood lava on Mars, flowing past a crater

Crater with lava flow
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Cool image time! The photo to the right, rotated, cropped, reduced to post here, was taken on December 3, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The title given to this image by the MRO science team is “Upstream Edge of Crater in Athabasca Valles.” The crater itself is a pedestal crater, uplifted from the surrounding terrain because it was more resistant to erosion.

The material to the east of the crater’s rim definitely appears to have flow characteristics, but is it wet mud, glacial ice, or lava?

To figure this out we need as always some context. The latitude, 8 degrees north, immediately eliminates mud or glacial material. This location is in the dry equatorial regions of Mars, where no near surface ice has yet been found. Thus, the flow features are likely hardened lava.

What direction however was the flow? Was it flowing to the north, widening as it moved past the pedestal crater? Or was it to the south, narrowing as it pushed past that crater? To answer this question we need to widen our view.
» Read more

Ingenuity completes 40th flight

Overview map
Click for interactive map.

As predicted by the Ingenuity engineering team on January 17, 2023, the Mars helicopter yesterday completed its 40th flight, flying approximately 92 seconds and 584 feet to the northwest to place it at the head of the hollow that Perseverance will travel to climb up onto the delta that flowed into Jezero Crater sometime in the past.

The green dot on the overview map to the right shows the helicopter’s position, post flight. The blue dot shows Perseverance’s present position. The red dotted line indicates the rover’s future route.

At the moment, only eleven images have been returned from the flight, and these only show the first 20 seconds of flight. The flight however has been added to the helicopter’s flight log, which shows that Ingenuity actually flew about 23 feet farther and 7 seconds longer than expected. This extra distance was likely because the helicopter needed to find a good landing site, using its upgraded software that allows it to fly over rougher terrain.

Machete Mesa on Mars

Machete Mesa on Mars
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Cool image time! The picture to the right, cropped to post here, was taken on November 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a variety of ridges in a region of Mars called Arabia Terra, which is also the largest transition zone between the Martian southern cratered highlands and the northern lowland plains.

While this picture illustrates some nice geological facts about Mars (see below), I post it simply because of the dramatic sharpness of the ridge on top of the mesa, which I guess is several hundred feet high, but only a few feet across, at most, at its peak. A hike along this ridgeline would be a truly thrilling experience, one that the future human settlers on Mars will almost certainly find irresistible. Put this location on your planned tourist maps of Mars. It will likely be an oft-visited site.
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Curiosity climbs onto the Marker Band

Panorama as of January 17, 2023
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Overview map
Click for interactive map.

Curiosity’s exploration of the foothills of Mount Sharp continues. The panorama above, cropped, reduced, and annotated to post here, was taken on January 17, 2023 by the rover’s right navigation camera. It looks forward across the flat marker band terrain that the rover has been studying for the past few weeks.

From orbit, this marker band appears very smooth and flat, and is found in many places on the flanks of Mount Sharp, always at about the same elevation. The arrows in the overview map to the right mark several places near Curiosity where the band is evident. The blue dot marks Curiosity’s present location, the red dotted line its planned route, and the yellow lines indicate the approximate area covered by the panorama above. The distance across the marker band to the uphill slope is about 500 feet.

Now that Curiosity is on the marker band, it no longer looks smooth. Instead, it is a flat plain of many uneven paving stones interspersed with dust. While not as rough as the Greenheugh Pediment, which Curiosity had to retreat from because it was too hard on the rover’s wheels, the marker band is hardly the smooth soft terrain implied by the orbital images.

These paving stones have also proven difficult to drill into, with Curiosity’s drill already failing twice previously because the rock was too hard. That hardness should not be a surprise, however, as this layer’s flatness in many places shows its resistance to erosion.

As it crosses this wide section of the marker band the science team will obviously be looking for more candidate drill sites. Sooner or later one should work.

The sea of dunes surrounding the Martian north pole

The sea of dunes surrounding the Martian north pole
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on December 5, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a collection of wormlike dunes located in the giant sea of dunes that surrounds the Martian north pole ice cap.

North is to the top. The season when this picture was taken was northern winter. The Sun is barely above the horizon, only 8 degrees high, and shining from the southeast. Because it is winter it is also dust season, making the atmosphere hazy and thus making the light soft. No distinct shadows, except that the sides of the dunes facing away from the Sun are darkly shadowed.

The consistent orientation of the dunes suggests that the prevailing winds blow from the northeast to create the steep-sided alcoves. The wind however might not be the only factor to form these dunes.
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A Martian river canyon?

A Martian river canyon?
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Today’s cool image highlights the biggest mystery of Mars that has baffled scientists since the first good pictures of its surface were taken in the early 1970s by the Mariner 9 orbiter. The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 24, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a very small segment of the 400-mile-long meandering canyon on Mars called Nigal Vallis. From the Wikipedia page:

The western half of Nirgal Vallis is a branched system, but the eastern half is a tightly sinuous, deeply entrenched valley. Nirgal Vallis ends at Uzboi Vallis. Tributaries are very short and end in steep-walled valley heads, often called “amphitheater-headed valleys.”

We can see one of those short tributaries on the image’s left edge. The overview maps below provide a wider view of this entire canyon.
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Searching for surface changes caused by the biggest recorded Martian quake

Location of May quake
The white patches mark the locations on Mars of the largest quakes detected by InSight

On May 4, 2022, the seismometer on the InSight Mars lander detected a 4.7 magnitude earthquake on Mars, the largest ever detected.

The map to the right shows the approximate location of that quake by the white patch with the green dot. (You can read the paper describing this quake here [pdf].) This is also the same approximate location of a small five-mile-wide crater known to have many slope streaks on its interior walls.

Slope streaks are a uniquely Martian geological feature whose origin remains unknown. They resemble dark avalanche streaks flowing downhill, but make no changes in the topography, and lighten with time. They also occur randomly throughout the year. Two slightly different theories for their formation suggest that the streaks are triggered by the fall of dust particles, though neither is proven or even favored.

If either of these theories are true, then the 4.7 magnitude earthquake at this location should have caused the formation of more streaks. To find out, scientists have used the high resolution camera on Mars Reconnaissance Orbiter (MRO) to compare that crater both before and after the quake to see if any new streaks has appeared. Below is a side-by-side comparison of these images.
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A collapse on Mars

A collapse on Mars
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The photo to the right, cropped, reduced, and enhanced to post here, was taken on October 27, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The full photo was simply labeled as a “collapse feature”, and because it contained a few other sinks to the north beyond the top edge of this cropped picture, it is unclear if the scientists were referring to this sink in particular.

This sink is the most interesting however, because it really looks like something had sucked material out from below, causing the surface crust to fall downward, intact except for some cracks along the perimeter of the collapse.

The overview map below as always provides some context that might explain what we are seeing.
» Read more

Ingenuity about to fly up onto the delta

Overview map
Click for interactive map.

The engineering team that operates the helicopter Ingenuity on Mars announced today that the next flight, #39, will go about 456 feet and travel to the northeast.

The green dot on the map to the right shows Ingenuity’s present location. The yellow lines indicate the territory within which this flight will head. If successful it will be the first time the helicopter has left the floor of Jezero Crater, and moved uphill onto the delta that flowed into that crater sometime in the far past.

The blue dot marks Perseverance’s present location. The dotted red line indicates its eventual planned route on that delta.

The engineers state that their flight goal is to “flight test new software”. This new software is supposed to allow Ingenuity to fly over rougher terrain. On the 38th flight, it proved its worth by not only flying over an area of rippled sand dunes, it landed between two.

This next flight, scheduled for sometime today, will be even more challenging, because the helicopter will have to fly upward above higher terrain.

China’s Mars orbiter and rover in trouble

Yesterday we reported a tweet from Scott Tilley that suggested engineers were having trouble establishing a communications link with China’s Mars orbiter Tienwen-1.

Today it appears that communications with China’s rover Zhurong have also not resumed following its winter hibernation from May until December.

The Post independently confirmed with two sources on Thursday that the rover should have resumed running by now, but no contact has been established.

Though Zhurong’s solar panels can be tilted to kick dust from them, during hibernation this is apparently not possible. Because the winter dust season this year was especially bad (killing InSight for example), it is possible that Zhurong experienced the same fate.

Zhurong had a 90 day mission, and instead lasted a year. Moreover, tt was never expected to survive a Martian winter. The achievement thus remains grand.

As for the Tienwen-1 orbiter, it would be a much bigger failure if communications cannot be re-established. China without question expected this orbiter to operate for years, even functioning as a communications link for later landers/rovers. Its loss will force a revision of later plans.

Defrosting Martian Dunes

Defrosting Martian dunes
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was a captioned image on January 6, 2023 from the science team of the high resolution camera on Mars Reconnaissance Orbiter (MRO). From the caption by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

In the late winter when first illuminated, the carbon dioxide frost at high latitudes will begin to sublimate. Over sand dunes, the defrosting spots and mass wasting on steep slopes produce striking patterns. This scene is especially artistic given the shapes of the dunes as well as the defrosting patterns.

» Read more

The dry and dusty equatorial regions of Mars

The dry cratered highlands of Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on October 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a cluster of craters filled with ripple dunes.

The color strip tells us something [pdf] about the surface materials here. The reddish-orange in the craters is thought to be dust. The greenish terrain above the craters is likely coarse rock or bedrock, covered with a veneer of dust.

There is no ice here, just dust that over time has become trapped in the craters and cannot escape. And though there is also dust on the surrounding terrain, there is not that much. The craters themselves are likely very ancient, based on their shape and the eroded condition of their rims.

» Read more

Drainage out of a Martian crater

Drainage out of a Martian crater
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Today’s cool image to the right, rotated, cropped, reduced, and sharpened to post here, not only gives us another example of a Martian geological feature that is unique to Mars and whose origins are not yet understood, it also shows what appears to have once been a lake-filled crater that over time drained out to the east through a gap.

This picture was taken on October 14, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The inexplicable geology is called brain terrain, and it fills the floor of the crater on the picture’s left side. The rim shows a gap, from which a meandering channel continues downhill to the east. The lake inside the crater might not have been liquid water, but ice. The channel might not have been formed by flowing water, but by a glacial flow downhill.

What makes this glacial evidence especially interesting is that it is located in a very different part of the Martian mid-latitudes.
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The soft icy Martian northern lowland plains

The soft icy Martian northern lowland plains
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In a cool image post last week, I noted that the near surface “ice sheets in the northern lowland plains are never … smooth, even if well protected.” The picture to the right, cropped, reduced, and sharpened to post here, provides an excellent example. It was taken on November 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It is winter, and the sunlight is coming from the southwest, only 27 degrees above the horizon. The mound on the left is soft, while the depression on the upper right appears to have sand dune ripples sitting on top of a flat glacial mound. This depression may be an eroded crater (no upraised rim) or it could be a sink caused by the sublimation of the near surface ice.

Everywhere else the flat plains are stippled with small knobs.

The overview map below provides more context.
» Read more

A spray of Martian hollows

A spray of Martian sinks
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Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 12. 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Dubbed simply as a a “terrain sample” by the science team, the picture was not taken as part of any specific research project, but instead to fill a gap in the orbiter’s shooting schedule so as to maintain the camera’s proper temperature. When MRO’s science team does this, they try to pick something in the area below that might be interesting. Sometimes they succeed, but often the features in the picture are nondescript.

The white line delineates the rim of a faint and very eroded small crater. Are the depressions that are mostly concentrated just to its south and east sinks or past impact craters? I haven’t the faintest idea. The overview map below helps to answer this question, but only partly.
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A hint at Mars’ past climate cycles

Terraced glaciers in Martian crater
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Cool image time! The photo to the right, cropped to post here, was taken on October 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a “layered feature” inside a small 4,500-foot-wide crater.

Located at 36 degrees north latitude, we are likely looking at glacial ice layers inside this crater, with each layer probably marking a different Martian climate cycle. The terraces suggest that during each growth cycle the glaciers grew less, meaning that less snow fell with each subsequent cycle. This in turn suggests a total loss of global water over time on Mars.

The overview map below gives us the wider context.
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A “What the heck?” glacier image on Mars

Glacial material on Mars
Click for full image.

Sometimes a cool image goes from bafflement to obvious as you zoom into it. The cool image to the right, cropped to post here, does the opposite. It was taken on October 11, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have purposely cropped it at full resolution, so that its eroded glacier nature is most obvious.

The cracks and hollows are likely caused by the sublimation of the near surface underground ice, breaking upward so that the protective surface layer of debris and dust collapses at some points, and cracks at others.

The overview map below further confirms the likelihood that we are looking at glacial features, but when we also zoom out from this close-up we discover things are not so easily explained.
» Read more

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