The rocky surface of Gediz Vallis on Mars came from landslides and water-induced debris flows from above

Looking south inside Gediz Vallis
Looking uphill into Gediz Vallis, in 2024, when this research was being done.

Overview map
This map from 2024 provides the context for the panorama above.
Click for interactive map.

Using the data the rover Curiosity gathered during its exploration of the canyon dubbed Gediz Vallis on the lower flanks of Mount Sharp (Aeolis Mons) inside Gale Crater on Mars, scientists have concluded that the rocky material came from above, flowing downhill in the far past in major boulder landslides and water-induced debris flows.

The panorama above was taken when Curiosity was in Gediz Vallis. The overview map to the right provides the context, with the white dotted line showing Curiosity’s actual travels, and the yellow lines indicating the approximate area covered by the panorama. From the paper’s abstract:

Curiosity investigated Gediz Vallis, a canyon within Aeolis Mons, indicating that it must have formed late in Gale’s history. At the center of Gediz Vallis is a topographic ridge, comprised of sedimentary rocks. In the region where Curiosity crossed the ridge, Arc Pass, the rover investigated the processes that formed the ridge.

Curiosity found that rocks in Arc Pass were formed by water flows rich in debris, and landslides, which originated from higher up Aeolis Mons. These transport processes were separated by episodes of wind erosion and alteration of the rocks by groundwater. These observations indicate that liquid water continued to be available for brief periods late in the history of both Gale crater and Mars. [emphasis mine]

As noted by the highlighted sentence, the geology once again says that water in some form shaped the surface. As the scientists add in the paper, however, “Any surface water was likely only intermittently available, interspersed with significant hiatuses of aeolian erosion and dry granular transport processes.” It remains to be seen exactly what state that water was in, whether liquid or ice, considering that Mars has always been too cold with too thin an atmosphere for liquid water to exist on the surface.

Curiosity spent more than a year in this part of Gediz Vallis, then traversed west into the parallel canyon, dubbed Valle Grande, that it has been climbing for the past two years.

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Tiny polygon ridges on Mars

Tiny polygon ridges on Mars
Click for original image.

Cool image time! The picture to the right, cropped and reduced slightly to post here, was taken on June 21, 2026 by the high resolution camera on the Mars rover Curiosity. It looks down to provide a close-up of the ground the rover is presently parked over, a surface covered with thousands of these tiny polygon ridges, all of which appear less than three inches across.

For a wider view and the overall context, see my post from June 24, 2026. While from a distance the ground at this point looked smoother than anything the rover has seen in more than five years since it entered the foothills of Mount Sharp, once it got close it discovered the ground was completely covered with these small polygons.

The picture to the right is part of a close-up mosaic of these polygons the science team is gathering using the high resolution camera.

The geology here is certainly puzzling. Polygon cracks are not unusual on both Earth and Mars, in places where the ground was once wet and then dried. In drying the material shrinks, producing polygon-configured cracks. On Earth those cracks often fill later with material that is more resistant, such as lava, which remains to form ridges when the surrounding dirt erodes away. Whether this was the process here on Mars however is not known. For one thing, why are these polygons so small? And why so uniform in size?

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Smooth on Mars is apparently not so smooth

Panorama on June 17, 2026
Click for full resolution. For original images, go here and here.

Overview map
Click for interactive map.

Last week I noted how the terrain that stood ahead of Curiosity in its travels on Mount Sharp on Mars appeared to be the smoothest the rover had seen in years.

This week it turns out that upon closer inspection, smooth on Mars is not as smooth as it seems. The panorama above, created from two pictures taken by the rover’s left navigation camera on June 17, 2026 (here and here), provides a much closer view of that smooth ground, and revealed that it isn’t actually smooth at all, but covered with small polygons. The inset on the left shows the area in the white rectangle at full resolution, making the patterned nature of the ground very obvious. From today’s update by the science team:

From up close, the parking spot looks anything but smooth. … There are polygons, veins, lamination, and probably more, once we inspect the higher-resolution images taken today. “Higher-resolution” is the key for why we were in for such a surprise! The features are quite small, a few centimeters across, and therefore we could not see them in the orbital images or from a distance in our navigation and mast camera images. The camera resolution from a distance just isn’t enough to see them. But up close, the terrain revealed all its beauty!

The blue dot on the overview map to the right marks Curiosity’s present position, the white dotted line its actual travels, the red dotted line its planned route. The yellow lines indicate roughly the area covered by the panorama above. The rim of Gale Crater can dimly be seen through the dusty atmosphere 20 to 30 miles away.

Explaining the geological process that caused this patterned surface is beyond my pay grade. My first guess would be it is related to the past presence of water, in the form of liquid or ice, but no one should take that guess very seriously.

As I have said many times, Mars is strange, Mars is wonderful, but above all, Mars is alien.

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Curiosity sees smooth ground for the first time in years

June 12, 2026 Curiosity panorama
Click for full resolution version. Click here, here, and here for original images.

Overview mapd
Click for interactive map.

Cool image time! The panorama above was created from three pictures taken on June 12, 2026 by the left navigation camera on the Mars rover Curiosity (see here, here, and here). It shows the immediate ground uphill in front of the rover, which appears to be the smoothest ground that Curiosity has seen in about five years, since it entered the foothills at the base of Mount Sharp in 2021.

Since then the terrain has been routinely boulder strewn. In one case, the ground was so rocky and rough that the science team had to back off from their original plans and find a different route.

The panorama above shows something wholly different, a patch of relatively smooth ground with only a scattering of sharp rocks protruding periodically from below. This ground is likely the rover’s first taste of what the science team calls the “yardang unit”, the light colored hills in the lower right of the overview map to the right. For years that team has looked at those hills, wondering what it would be like to drive Curiosity on them. Their geology suggests a much softer terrain, sand shaped into dunes (yardangs) by the wind. The unknown was always whether the ground was structurally strong enough for the rover to traverse it.

It looks like they are about to get their first clue. Based on the panorama above, the ground appears very promising.

On the overview map, the blue dot marks Curiosity’s present position, with the red-dotted line is planned route and white-dotted line its actual travels. The yellow lines indicate approximately the area covered by the panorama.

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Curiosity’s looks up Valle Grande to its future travels

Panorama, June 8, 2026
Click for high resolution. For original images go here, here, and here.

Overview map
Click for interactive map.

Cool image time! The panorama above was created by me using three pictures taken today by the left navigation camera on the Mars rover Curiosity (see here, here, and here).

The overview map to the right provides the context. The white dotted line indicates Curiosity’s actual travels, while the red dotted lines its planned route, both in the past and in the future. The blue dot marks its approximate position when these images were taken. The yellow lines indicate approximately the view.

The panorama looks up this spectacular valley, which the science team has named Valle Grande. The red dotted line on the panorama is my guess as to the rover’s future route. It will likely not follow such a straight path, but weave back and forth as the science team directs it to look at interesting geological features along the way.

What remains unknown is the route the rover will take once it reaches those light-colored hills in the distance. The science team so far not indicated any chosen route through those hills. I suspect they want to get closer and do some on-site scouting before making any decision. The nature of that light terrain remains unknown. It could be easily traversed, or it could be a problem. From a distance it looks very soft, and thus it will likely required close inspection to make any definite plans.

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Curiosity drill samples taken at different elevations show different Martian climates

Core samples used in study
Figure S1 of the study, showing the location
of the core samples. Click for source.

By comparing 20 different Curiosity drill samples taken during the rover’s fourteen years on Mars, scientists have detected hard evidence that the climate in Gale Crater was distinctly different at different elevations, for long periods.

This study shows that hematite can also be a marker of climate changes based on its crystallite sizes and structures, which change under different temperatures. The scientists found that hematite crystallites from higher elevations in Gale Crater were less than 10 nanometers in size, while crystallites from lower locations were generally larger, reaching up to 65 nanometers. These findings aligned with the observations that samples from higher elevations contained both hematite and goethite, while lower elevation samples lacked goethite.

They concluded that, under warmer conditions when the pH of water is neutral or slightly alkaline, goethite can transform into hematite. These warmer conditions also favored an increase in hematite crystallite size in the deeper layers of Gale Crater through a process known as Ostwald ripening, in which smaller crystallites dissolve and contribute to the growth of larger ones. “This can tell you that the top layers were colder and didn’t have enough water, or the water presence was relatively short-lived, so the crystallites didn’t have sufficient time and conditions to grow in size,” said Peretyazhko. “But the lower layers had longstanding warm water that allowed those crystallites to grow.”

The white dots on the map to the right shows the location of the drill samples used, taken along Curiosity’s travels as it climbed Mount Sharp. Overall Curiosity has climbed about 2,500 feet, so the differences found the samples mark the past climate differences between the crater floor and the mountain’s foothills. According to this data, the crater floor had long-standing water in some form, exceeding millions of years. At higher altitudes there was less and less, and it was there for increasingly shorter periods.

As the press release notes, “A unique highlight of this study is that the data comes from Martian samples, rather than from theoretical modeling.” Similar conclusions from earlier Curiosity data required Earth proxies and computer modeling. This result is from hard data from Mars.

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Curiosity looks closely at the broken slab that had been stuck on its drill bit

The rock Atacama
Click for original image.

As expected, the science team for the Mars rover hasdecided before moving on it would take a close look at the 28 pound slab of rock that had been stuck on its drill bit and when finally dropped free broken into several pieces when it hit the ground.

The top picture to the right, cropped and reduced to post here, shows that entire rock, labeled Atacama by the science team. The two insets below are close-ups of the delicate layering at the rock’s left edge as well as the drill hole itself. From team’s update today:

The highest-priority activities after liberating the drill included imaging the drill with Mastcam and ChemCam RMI, and imaging into the now-empty drill hole with MAHLI (the image above). The science team made the most of the freshly-broken surfaces created when Atacama fell back to Mars, and the freshly-exposed sand once hidden underneath Atacama.

The exposed sand is off camera, to the right. Expect a paper published about that sand, buried likely for millions of years, sometime in the next year or so.

The delicate flutes at the rock’s left edge are somewhat common rock features seen by Curiosity, made possible by Mars’ thin atmosphere and its one-third Earth gravity. On Earth the gravity and weather generally destroys such things. On Mars the lack of violent weather and light gravity allows them to form, and the thin wind even helps in their formation.

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Curiosity unintentionally picks up a rock slab

Sequence showing slab picked up and then dropped
Click for movie. Original images found here, here, here, and here.

In their latest drilling campaign using the drill on the Mars rover Curiosity, the science team picked up a big surprise that could have been a serious problem, but turned out all right in the end. When they tried to extract the drill from the hole, the drill instead stayed stuck to the rock, and picked the whole rock up instead.

The four images to the right show the sequence, sourced from here, here, here, and here.

On April 25, 2026, Curiosity drilled a sample from a rock nicknamed “Atacama,” which is an estimated 1.5 feet in diameter at its base, 6 inches thick and weighs roughly 28.6 pounds (13 kilograms). When the rover retracted its arm, the entire rock lifted out of the ground, suspended by the fixed sleeve that surrounds the rotating drill bit. Drilling has fractured or separated the upper layers of rocks in the past, but a rock has never remained attached to the drill sleeve. The team initially tried vibrating the drill to shake off the rock, but saw no change.

Then, on April 29, they tried reorienting Curiosity’s robotic arm and vibrating the drill again. Imagery in the GIF shows sand falling from Atacama, but the rock stayed attached to the rover.

Finally, on May 1, Curiosity’s team tried again, tilting the drill more, rotating and vibrating the drill, and spinning the drill bit. The team planned to perform these actions multiple times but the rock came off on the first round, fracturing as it hit the ground.

Had they not been able to release the rock it could have seriously impacted the mission, even ended it.

As noted by the science team in their own update today about this situation:

Future activities involve wrapping up the drill campaign on Atacama and, nominally, seeking a more firmly rooted drill target in order to collect drill tailings for analysis, which were lost from Atacama as part of the effort to dislodge the drill bit from the rock.

In other words, they are going to have hunt around for a better drill spot, as they really do want to study some drill samples at this location. They have left the boxwork area and have moved uphill closer to the pure sulfite unit, and want to see how the geology has changed.

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Curiosity looks at a small crater as it climbs Mount Sharp

Antofagasta crater
Click for full resolution. Click here, here, and here for original images.

Cool image time! The panorama above, created from three pictures taken by the right navigation camera on the Mars rover Curiosity (see here, here, and here), takes a look at a small relatively fresh crater on the slopes of Mount Sharp. From an update from the rover’s science team yesterday:

At the beginning of the week, Curiosity arrived right on target on the rim of the 10-meter (33 feet) “Antofagasta” crater. The crater looked fresh and deep as we had hoped with a nice well-defined rim that didn’t look too eroded, but the bottom of it turned out to be filled with dark rippled sandy material that covered up the most interesting rock layers. There were a few rock exposures just above the sand cover that seemed like they might have been deep enough to have been sheltered from space radiation between the time their sediments were deposited and the crater-forming impact, but reaching them from the rim would have put the rover at such an awkward angle that we wouldn’t have been able to deliver the sample to the instruments.

Overview map
Click for interactive map.

It’s possible that we might have been able to get into a better position by instead placing the rover on the rippled crater fill, but the chance that the rover could get stuck in all that sand made it much too high a risk. We also looked at the nearby blocks in case they could have been ejecta from the crater, but since all the rocks visible in the crater wall looked very similar to each other, there wasn’t a good way to tell which ejecta blocks might have come from the deeper layers of the crater. Because of this, the team decided against attempting to drill in or around the crater.

The overview map to the right provides the context. The blue dot marks Curiosity’s location when the pictures above were taken. The yellow lines roughly indicate the area covered by the panorama. The red dotted line marks the future planned route, the white dotted line the rover’s actual travels.

Note the flat rocks in the foreground of the panorama, all part of the crater’s rim. Each looks like a large flat paving stone that was very precisely shattered into numerous tiny pieces, all about the same size. Very strange. On Earth you’d assume some craftsman had laid these small pieces down like tiles, but of course, that couldn’t have happened on Mars.

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Martian mountains on Mount Sharp

Panorama looking up Mount Sharp
Click for larger full resolution image. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! The panorama above was created using two pictures taken by the high resolution camera on the rover Curiosity on Mars (here and here).

The overview map to the right gives the context. The blue dot marks Curiosity’s position on the day before these pictures were taken, climbing through the foothills on the flanks of Mount Sharp. I do not know if it traveled again before taking these two pictures above. The white dotted line its past travels, while the red dotted line its planned future route. At present Curiosity has climbed about 3,500 feet up the mountain. It is still about 15,000 feet below the peak, which is about 25 miles away and not visible from here.

The yellow lines indicate where I think the panorama is looking, though I admit that I am not sure. The view is distant, since this is high resolution camera. This panorama might actually be looking in a completely different direction, downhill at one of the hills that Curiosity previously drove past. The air is very dusty, which means if the rim of Gale Crater is in the background, 20-30 miles away, we can’t see it.

Regardless, the science team has finally finished its many nine-month-long survey of the boxwork geology, and has sent Curiosity climbing again. I think these pictures are part of their review of the future terrain, as they plan the rover’s route through the lighter-colored sulfate terrain higher on the mountain. If instead they are looking downhill, they were taken both to review previously viewed geology as well as to measure the dustiness of the atmosphere.

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Growing damage to the wheels of the Curiosity Mars rover

Close-up of the wheel in the worst condition
Images cropped and reduced to post here. For the original images go here and here.

Survey of wheels

Every few months or so the Curiosity science team uses one of the rover’s cameras to do a survey of the rover’s wheels to track their condition. Since early in the mission they had found the wheels were not holding up as well as expected as they rolled over the rough terrain in Gale Crater and on Mount Sharp, and so they take great care in how they move the rover as well as review the wheels regularly.

A year ago it had appeared that the damage to one particular wheel had increased, to a point where its outer section might even break off.

Yesterday the science team did another survey, as shown in the picture to the right.

The two photos above (found here and here) focus on one particular wheel of that survey, which I suspect is the same wheel that was the focus of last year’s post. After taking the first image on the left the team moved Curiosity so that the other side of the wheel could be photographed. As you can see, the damage is extensive, so much so that it is possible the wheel could collapse entirely in the not-to-distant future.

It also looks like another wheel is beginning to see similar damage (see here and here), though not yet as extreme.

The good news is that Curiosity has six wheels, and that it can continue to travel even with the loss of one or maybe two wheels. It also appears that future terrain might not be so rocky.

The bad news is that this wheel damage is likely the one problem that will likely end the mission, possibly sooner than anyone would like. And from these photographs, that end might be sooner rather than later.

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Curiosity looks uphill at its upcoming travels

Panorama looking up Mount Sharp
Click for original.

Overview map
Click for interactive map.

Cool image time! Since May 2025 Curiosity has been exploring in great detail the boxwork formations located on the lower slopes of Mount Sharp. It is now about to complete those investigations, with the Curiosity science team beginning their planning for moving onward and upward.

The panorama above, enhanced to post here, was taken on March 2, 2026 by the rover’s right navigation camera. It looks uphill along the valley that Curiosity is in toward the mountainous region the rover is targeting. Note that the peak of Mount Sharp is not visible, being more than 25 miles away beyond the horizon and about 15,000 feet higher up.

The blue dot on the overview map to the right mark Curiosity’s present position. The yellow lines indicate roughly the area this panorama covers. The red dotted line marks the rover’s approximate planned route, while the white dotted line indicates Curiosity’s actual travels.

Right now Curiosity is traveling through a geological layer the scientists have dubbed the sulfate unit. The lighter colored hills seen on the horizon have also been identified as sulfate, but believed to be much more pure. The geology there should be very different. Instead of rough and rocky it could be like traveling over soft porous sand. This however is merely a guess on my part, based on imagery of those light-colored hills.

The actual route through those hills however remains unknown. Either the science team has not yet released it, or is still trying to figure out the best way through.

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Communications resume with Mars

First images back from Curiosity and Perseverance
Go here and here for the original images.

It appears the solar conjunction that has blocked all communications with the rovers and orbiters for the past three weeks around Mars has now fully ended, with the first new images appearing today from both Curiosity and Perseverance.

The two images to the right were downloaded today. The top image was taken on January 20, 2026 by Curiosity’s front hazard avoidance camera. It appears to be looking uphill in the direction the rover is soon to travel, climbing Mount Sharp. If you look closely you can see the mountain’s higher ranges on the horizon, just to the right of the rover itself.

The bottom picture was actually taken on January 15, 2026 by Perseverance, but was only downloaded today. Both science teams had programmed their rovers to take images throughout the conjunction, scheduled for download when communications resumed.

The picture was taken by Perseverance’s left high resolution camera located on top of the rover’s mast. It looks down at the ground near the rover at the pebbles and rocks that strewn the relatively smooth surface of the terrain west of Jezero crater.

Neither image is particularly ground-breaking. What is important however is that both images prove the rovers are functioning as expected. Expect a lot more data to arrive in the next few days, all gathered during three weeks of blackout.

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The three week communications blackout from Mars has begun

Last image before blackout from Curiosity
Click for original.

Last image before blackout from Perseverance
Click for original.

The two images to the right, both downloaded today (here and here) from the Mars rovers Curiosity (top) and Perseverance, illustrate quite clearly the beginning of the three-week-long communications blackout from Mars caused every two years when the orbits of Earth and Mars places the Sun in-between. As the Curiosity science team noted in a December 22, 2025 update:

This holiday season coincides with conjunction — every two years, because of their different orbits, Earth and Mars are obstructed from one another by the Sun; this one will last from Dec. 27 to Jan. 20. We do not like to send commands through the Sun in case they get scrambled, so we have been finishing up a few last scientific observations before preparing Curiosity for its quiet conjunction break.

Apparently engineers were able to squeeze data and images from Mars for a few extra days, but the incomplete nature of these two pictures — combined with the lack of any other new images today — tells us that the blackout has definitely begun. That they were able to get these additional images after conjunction began suggests the blackout might also end a bit earlier than expected.

Though there is always a concern that something could go wrong while communications are blocked, the risks are small. The science teams for all the Mars orbiters and rovers have dealt with this situation now almost a dozen times since operations became routine there more than a quarter century ago.

The only spacecraft at real risk this conjunction is Maven. Contact was lost from it in early December for unknown reasons, and all efforts to regain communications have so far failed. All engineers know from the little data they have gotten back is it appears to be tumbling. This three week blackout will make any chance of recovery extremely unlikely.

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No contact with Mars’ rovers for the next month

The Sun is about going to cause a month-long break in communications with Curiosity and Perseverance, the two rovers on Mars.

This communications pause occurs every two years, when the orbits of Earth and Mars align with the Sun in between.

This holiday season coincides with conjunction — every two years, because of their different orbits, Earth and Mars are obstructed from one another by the Sun; this one will last from Dec. 27 to Jan. 20. We do not like to send commands through the Sun in case they get scrambled, so we have been finishing up a few last scientific observations before preparing Curiosity for its quiet conjunction break.

This is not a unique situation. Both rovers have gone through conjunction several times previously. The science teams will place the rovers in secure positions to hold them over during the break.

As for the orbiters circling Mars, it isn’t clear how much their operations will be impacted. The update at the link above makes no mention of them, and my memory says communications with them is less hampered, though reduced somewhat.

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Curiosity’s exploration of boxwork on Mount Sharp

Curiosity panorama, December 18, 2025
Click for high resolution panorama. For original images, go here, here, and here.

Overview map
Click for interactive map.

Cool image time! The panorama above was created from three photographs taken on December 18, 2025 (here, here, and here) by the right navigation camera on the Mars rover Curiosity.

The view is north, looking down the flanks of Mount Sharp and across the floor of Gale Crater to its rim about 20 to 30 miles away. In comparing this view with a similar one taken in July, it is obvious that the Martian atmosphere has become far dustier during the last six months. The rim and the mountains beyond are hardly visible now through the haze.

The blue dot on the overview map to the right marks Curiosity’s present position. The yellow lines indicate roughly the area covered by this panorama. The while dotted line indicates the rover’s travels, while the red dotted line its planned routes.

As you can see by both the rover’s tracks in the panorama above and the white dotted line in the overview, Curiosity has been traversing back and forth across the boxwork formation of criss-crossing ridges for more than half a year, as the science team attempts to decipher what caused these ridges and hollows. They have also done some drilling in this effort.

The science team has been getting close to the day it will move on, resuming Curiosity’s climb of Mount Sharp, but they keep finding things amidst this boxwork that requires additional study. For example, consider this from yesterday’s update:
» Read more

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Curiosity looks downhill at past travels

Curiosity looks downhill
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on November 6, 2025 by the left navigation camera on the Mars rover Curiosity.

The picture looks north across Gale Crater, its distant rim about 20-30 miles away barely visible in the dusty atmosphere. In the foreground can be seen Curiosity’s recent tracks, showing how the science team had it travel back and forth several times, probably to check out several different interesting nearby ground features, as well as see how the ground changed by that travel. The rover has been traveling in an area called boxwork, a series of small intercutting ridges and hollows. Several of those ridges can be seen just beyond the tracks.

The red dotted line indicates my rough estimate as to the rover’s route uphill to get to this point, traveling up and to the left and following ridges just out of view.
» Read more

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Martian boxwork on the flanks of Mount Sharp

The boxwork on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 5, 2025 by the left navigation camera on the Mars rover Curiosity.

The picture looks north and downhill from the lower flanks of Mount Sharp, inside Gale Crater. In the far distance on the horizon can be seen the crater’s northern rim, about 20 to 30 miles away. As it is now moving into the dusty season on Mars, the haze has increased from only a month ago, making it hard to see many distant details.

In the foreground can be seen clearly the light-colored ridges of the boxwork that the rover has been traversing for the past three months, with one rover track visible on the nearest ridge. Unlike the very rocky and boulder-strewn terrain the rover has seen in most of its travels on Mount Sharp, this boxwork seems smoother.
» Read more

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Has Curiosity stumbled upon a small slope streak?

Is that a slope streak in the lower right?
Click for original.

Overview map
Click for interactive map

In reviewing the pictures downloaded today by the Mars rover Curiosity, I noticed something very intriguing in the pictures taken by rover’s two navigation cameras. One such picture is above, taken by the right navigation camera and looking west across the boxwork ridges that Curiosity has been traversing for the past two months. You can see two such ridges in the right foreground, cutting diagonally from left to right.

The overview map to the right gives the context, with the blue dot marking Curiosity’s position. The white and red dotted lines indicate its actual and planned routes respectively, with the top inset zooming in to show the recent travels more clearly. The yellow lines show the approximate area covered by the picture above.

Note the dark streak in the lower right of the picture. The bottom inset on the overview map shows this streak more closely. To my eye, it strongly resembles a slope streak, a strange geological feature unique to Mars.

If I am right, expect the rover team to focus in on this streak. The cause of slope streaks remains unknown. From orbit, the streaks look like avalanches at first glance, but they don’t change the topography, have no debris pile at their base, and sometimes even travel up and over rises as they head downhill. They can occur randomly throughout the year, can be bright or dark, can occur anywhere, and fade with time.

There are a number of theories (see here, here, and here) attempting to explain their cause, but none has been confirmed. If this is a streak, it will be the first that any scientist can see up close.

It is also very likely my guess is wrong, and this is not a streak. Stay tuned for updates.

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Strange rocks on Mars

Coral on Mount Sharp!
Click for original image.

Float rock in Jezero Crater
Click for original image.

Time for two cool images, from two different craters separated by thousands of miles on Mars! The first image to the right, cropped, reduced, and sharpened to post here, was taken on July 24, 2025 by the Mars Hand Lens Imager (MAHLI) at the end of the robot arm of Mars rover Curiosity, and shows a really strange rock formation that resembles a piece of coral on Earth.

Curiosity has found many small features like this one, which formed billions of years ago when liquid water still existed on Mars [in this region]. Water carried dissolved minerals into rock cracks and later dried, leaving the hardened minerals behind. Eons of sandblasting by the wind wore away the surrounding rock, producing unique shapes.

The second image, cropped, reduced, and sharpened to post here, was taken on August 5, 2025 by the left high resolution camera on the rover Perseverance. It shows what appears what geologists call a “float rock”, something that was created geologically somewhere else and transported to this location later.

In this case the rock appears lavalike in nature. Since Perseverance is exploring the exterior rim of Jezero Crater, we could be looking at the impact melt created when the bolide hit the ground to create the crater. Material would be instantly melted as well as flung outward as ejecta, with this strangely shaped rock an example.

The problem with this theory however is that the rock appears to have solidified well before it hit the ground at this location. Its shape also suggests it solidified within a crack, thus molding it to this shape, with its top once at the bottom, the lava flowing downward. The mystery then is how it ended up as we see it, upside down and exposed.

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