Tag: geology

Peeling thin layers on a Martian plateau

1:22 pm

Peeling thin layers on Mars
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on May 14, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels as “light-toned layered deposits.”

Their focus, rightly from a geologist’s perspective, is the contrast in color between different layers, suggesting different composition and thus a different formation history for each layer.

To me, what made this feature appealing is the thinness and number of its layers. It reminded me of fillo pastry, “unleavened flour dough formed into very thin sheets or leaves.”

If you look at the full image you will see that cropped section only covers one edge of a tongue-shaped plateau, with similar layers revealed along its entire cliff wall. It is almost like those layers have been peeling off for eons to leave the plateau behind.

The location below gives some context.
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New data suggests Gale Crater was never filled with lake

12:28 pm

The uncertainty of science: A new review of data from Curiosity now suggests that Gale Crater was not filled with a lake in the past — as generally believed — but instead simply had small ponds on its floor.

Previous analyses of data from Curiosity have relied heavily on a measure called the chemical index of alteration to determine how rocks were weathered over time. Joseph Michalski at the University of Hong Kong and his colleagues have suggested that because this measure was developed for use on Earth, it may not be valid in the extreme Martian climate.

Instead, they analysed the concentrations of various compounds that are expected to change based on different types of weathering over time. They found that some of the layers of rock Curiosity examined did interact with water at some point in their past, but more are likely to have formed outside of the water. “Over hundreds of metres of strata, it seems that the only layers that are demonstrably lacustrine [formed in a lake] are the lower few metres,” says Michalski. “Of the rocks visited by the rover… the fraction that is demonstrably lacustrine is something like 1 per cent.”

These rocks were mostly in the lowest few metres of sediments in the crater, suggesting the lake was not nearly as deep or extensive as we thought. “There was likely a small lake or more likely a series of small lakes in the floor of Gale crater, but these were shallow ponds,” says Michalski.

This conclusion also aligns with other recent work proposing that Gale Crater was always cold and never had running water.

None of this is proven, one way or the other, though this new conclusion would make it easier to explain Mars entire geological history. Trying to create models for Mars’ past climate that allowed large amounts of liquid water on its surface have so far been difficult at best, and have generally been unconvincing. Eliminating the need for liquid water will make explaining Mars’ geology much simpler.

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Perseverance’s first sample grab fails

11:49 am

Perseverance's first core sample drill location
Click for full image.

The first attempt by the Mars rover Perseverance to obtain a core sample has apparently failed.

The failure does not appear to be technical. All the hardware appears to have worked. When they inspected the interior of the hollow core drill however no sample was seen inside.

“The sampling process is autonomous from beginning to end,” said Jessica Samuels, the surface mission manager for Perseverance at NASA’s Jet Propulsion Laboratory in Southern California. “One of the steps that occurs after placing a probe into the collection tube is to measure the volume of the sample. The probe did not encounter the expected resistance that would be there if a sample were inside the tube.”

…”The initial thinking is that the empty tube is more likely a result of the rock target not reacting the way we expected during coring, and less likely a hardware issue with the Sampling and Caching System,” said Jennifer Trosper, project manager for Perseverance at JPL. “Over the next few days, the team will be spending more time analyzing the data we have, and also acquiring some additional diagnostic data to support understanding the root cause for the empty tube.” [emphasis mine]

Do the highlighted words remind you of anything? They do for me. The first thing I thought of when I read this was the drilling mole for InSight’s heat sensor. It failed in its effort to drill into the Martian surface because the nature of the Martian soil was different than expected. It was too structurally weak, and would break up into soft dust rather than hold together to hold the mole in place.

In the case of Perseverance, it appears right now (though this is not confirmed) that the drill successfully drilled into the ground, with its core filling with material, but when the core was retracted, that material simply fell out, as if it was too structurally weak to maintain itself inside the core.

The photo above of the drill hole and its thick pile of dust appears to support this hypothesis. Even though they drilled into what looked like bedrock the act of drilling fragmented that bedrock apart.

I am speculating based on limited information, so I am likely wrong. For example, the drill certainly has sensors to detect the density and structural strength of the rock it is drilling into. The engineers will check those numbers during drilling. If the rock doesn’t appear dense enough or structurally strong enough for a core sample, I would expect them to pick a different spot.

If true however it means that obtaining core samples at many locations in Jezero Crater will simply not be possible. This does not mean no samples will be obtained, because there are definitely places on Mars where the ground’s structure is solid enough for this method to work. Curiosity definitely found this to be true, when if found several places on Vera Rubin Ridge where its drill didn’t have the strength to penetrate the rock.

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Ingenuity successfully completes 11th flight

1:14 pm

Ingenuity about to land
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Ingenuity has successfully completed its 11th flight, safely touching down at approximately its planned landing spot. From the science team’s tweet:

[Ingenuity] has safely flown to a new location! Ingenuity flew for 130.9 seconds and traveled about 380 meters before landing.

The image to the right, reduced to post here, was taken mere seconds before landing, and shows the helicopter’s shadow directly below it on the ground.

This particular flight was the first that did not push Ingenuity’s abilities, merely flying in a straight line to put it in a good position for later flights and to keep it ahead of Perseverance.

So far they have only released five images from the flight. Expect the rest to be downloaded from Perseverance in the next few days.

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Curiosity: Nine years since landing on Mars and the way forward

9:55 am

The way forward for Curiosity
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In today’s Curiosity update written by planetary geologist Abigail Fraeman, she noted this significant fact:

Project scientist Ashwin Vasavada pointed out a great fact at the beginning of planning today: At around 4 o’clock in the afternoon on Sol 3199 (the first sol in the plan we are creating today), Curiosity will begin its 10th Earth year on Mars. In the last nine years, the rover has traveled 26.3 km [16.3 miles], climbed over 460 m [1,509 feet] in elevation, and collected 32 drilled samples of rock.

Her update includes the first image taken by Curiosity upon landing, a view of Mount Sharp using the rover’s front hazard camera. In that picture, the mountain is far away, as the rover was sitting on the flat floor of Gale Crater.

The photo above, cropped and enhanced to post here, was taken yesterday by one of Curiosity’s navigation cameras, and looks out across the rocky mountainous terrain the rover is soon to travel. As Fraeman also notes,
» Read more

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White blobs on Mars

1:50 pm

White blobs on Mars
Click for full image.

Time for another “What the heck?” image. The photo to the right, cropped to post here, was taken on May 18, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what appears to be a series of white circular features aligned with a ridge line.

Are these eroded craters? Maybe, but their alignment with those ridges suggests otherwise. If you look at the full image, you will see further parallel ridges to the north and south, also with similar circular blobs lined along them. Furthermore, the flat surrounding terrain, part of the northern lowland plains north of the resurgences from Valles Marineris, has a scattering of very normal looking craters, with distinct rims and even some glacial material within. As this is at 44 degrees north latitude, the presence of glacial material inside craters is not surprising.

Thus, the white blobs are likely not craters, but some form of eruptive material from below, coming up along those ridges which are probably faultlines. The whiteness suggests that material is water ice, but this of course is unconfirmed.

The question is of course, why? What would cause water ice to erupt along these faultlines? And why are such features not seen elsewhere? Faults and underground ice are common on Mars. Yet, I don’t remember seeing features such as this in any other Martian images.

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Curiosity’s wheels: a good news update

11:13 am

Curiosity's wheels
Click here and here for the original images.

For the past few weeks Curiosity has been traveling across some of the roughest terrain it has seen on Mars, since landing in Gale Crater in August 2012. The rover is now roving among the high cliffs and foothills at the very base of Mt Sharp, with the ground covered with rocks, boulders, plates of bedrock, and all sorts of protrusions.

On August 1st the rover team used its cameras to do another survey of the rover’s wheels to see how they fared during that journey. The two images to the right compare the same area on the same wheel after the most recent 16 sols of travel. This is the same wheel I have focused on since 2017. Overall, the damage in the most recent picture seems almost identical to the previous picture. In fact, if you compare today’s image with the annotated version of the 2017 photo, found here, you can see how little things have changed since then.

From this one wheel it appears that the wheels are continuing to hold up quite well. The Curiosity team of course needs to review all the images of all the wheels, but based on this one comparison, it looks like their long term strategies for mitigating damage to the wheels is working, even in the rough terrain the rover is presently traversing.

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Martian lava flooded crater?

10:00 am

lava flooded crater?
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A quick cool image! The photo to the right, rotated, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) more than a decade ago, on June 1, 2010. I post it now because it is today’s MRO picture of the day, and is definitely cool. The caption:

One of a few “scaly-looking” inselbergs within regional platy-ridged flows in Elysium Planitia. This inselberg has a broken and blocky appearance with some of the blocks being tilted. Could this be the remnant of a once extensive mantling deposit? An inselberg is an isolated hill or mountain rising abruptly from a plain.

The wider image by MRO’s context camera below, also rotated, cropped and reduced to post here, illustrates even more forcefully how isolated this circular set of blocks is.
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The sublimating surface of Mars’ northern plains?

3:30 pm

Sublimating patches on Mars?
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Cool image time! The photograph to the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on May 27, 2021. A sample image, likely taken not as part of any specific scientist’s research but by the camera team in order to maintain the camera’s temperature, shows an area of the Martian northern plains that appears filled with rough scattered depressions, possibly caused by sublimation of buried ice.

The location, at 54 degrees north latitude, is far enough north to easily have a lot of buried ice. It is also only about 40 miles to the east of Milankovič Crater, where scientists have found many scarps that appear to have exposed layers of ice in their cliff faces.

However, the location has other components that must raise questions about this sublimating ice hypothesis.
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The view of Jezero Crater, from both Ingenuity and Perseverance

1:10 pm

The view from Ingenuity during 10th flight
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Cool image time! Today the Perseverance science team released the 200 images that Ingeniuty took during its 10th flight on July 24, 2021.

The photo to the right was taken about 25 seconds before the helicopter landed, and looks to the southwest. In the foreground can be seen the ridge of rocks and pebbles that the scientists sent Ingeniuty to photograph. In the distance can be seen the rim of Jezero Crater, about 7.5 miles away, with some rounded hills that sit in the crater floor about 5.5 miles away.

The white box indicates the area covered by two high resolution images taken by Perseverance on July 28th that I have combined into the panorama below.
» Read more

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Scientists: Clay, not liquid water, explains radar data under Martian south icecap

9:57 am

The uncertainty of science: In a new paper scientists claim that clay materials, not liquid water, better explain the radar data obtained by orbital satellites, initially hypothesized to be liquid water lakes under Mars’ south polar icecap.

Sub-glacial lakes were first reported in 2018 and caused a big stir because of the potential for habitability on Mars. Astrobiologists and non-scientists were equally attracted to the exciting news. Now, the solution to this question, with great import to the planetary science community, may be much more mundane than bodies of water on Mars.

The strength of this new study is the diversity of techniques employed. “Our study combined theoretical modeling with laboratory measurements and remote sensing observations from The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on NASA’s Mars Reconnaissance Orbiter. All three agreed that smectites can make the reflections and that smectites are present at the south pole of Mars. It’s the trifecta: measure the material properties, show that the material properties can explain the observation, and demonstrate that the materials are present at the site of the observation,” Smith said.

This paper is only one of several recently that has popped the balloon on the liquid lake theory. Nothing is actually proven, but the weight of evidence is definitely moving away from underground liquid water under the south pole icecap.

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The nearest hill to China’s Zhurong

3:45 pm

Pitted cone near Zhurong
Click for full image.

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) today released a pair of images the camera took on June 28, 2021 of the nearest pitted cone to China’s Zhurong rover.

The stereo anaglyph to the right, cropped and reduced to post here, allows you, with blue-red 3D glasses, to see the cone in three dimensions. Quite impressive. As noted by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona in his caption,

This image completed a stereo pair of a region just west of where the Zhurong rover landed in southern Utopia Planitia.

The cutout is from a portion of the stereo anaglyph, showing an enigmatic pitted cone. Is this cone composed of sediments or volcanic materials? The sharp bright features surrounding the cone are aeolian (wind-blown) landforms.

According to McEwan, the hill itself is about 200 to 220 feet high, with the pit at its top about 60-65 feet deep.

While McEwan has told me this cone would be his primary target if he was running Zhurong, it appears the Chinese are instead heading south toward the largest nearby crater, and on the way inspecting the parachute, fairing, and heat shield discarded just prior to landing.

The mosaic below from three MRO context camera images provides a wider overview.
» Read more

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Fractured crater close to the Phoenix lander on Mars

2:37 pm

Fractured crater on Mars
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Cool image time! The photo to the right, cropped to post here, was taken on May 3, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a remarkably fractured crater that lies only a few miles to the southeast of where the now-inactive Phoenix lander put down back in 2008, at the very high latitude of 69 degrees north.

Phoenix was purposely sent to this high latitude to find out what the ground and atmosphere was like there. It found the following:

Phoenix’s preliminary science accomplishments advance the goal of studying whether the Martian arctic environment has ever been favorable for microbes. Additional findings include documenting a mildly alkaline soil environment unlike any found by earlier Mars missions; finding small concentrations of salts that could be nutrients for life; discovering perchlorate salt, which has implications for ice and soil properties; and finding calcium carbonate, a marker of effects of liquid water.

Phoenix findings also support the goal of learning the history of water on Mars. These findings include excavating soil above the ice table, revealing at least two distinct types of ice deposits; observing snow descending from clouds; providing a mission-long weather record, with data on temperature, pressure, humidity and wind; observations of haze, clouds, frost and whirlwinds; and coordinating with NASA’s Mars Reconnaissance Orbiter to perform simultaneous ground and orbital observations of Martian weather.

Below is an overview map showing the location of both this crater and the Phoenix lander.
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A hiker’s view from Mount Sharp

10:10 am

A hiker's view of Gale Crater, taken by Curiosity
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A quick cool image! The photo to the right, reduced to post here, was taken yesterday by Curiosity’s left navigation camera. It looks west across the floor of Gale Crater, at the base of a nearby butte.

The crater rim, as seen by the distant mountains, is about 25 miles away. The butte that towers above Curiosity is probably no more than 50 feet high.

Below is a panorama showing the full view to the west, with Navarro Mountain (the nearby 450-foot-high foothill at the base of Mount Sharp) on the left edge. Based on the rover’s planned route, it will travel to the right of the butte rather than climbing up onto the saddle on the left. This will take it to the western side of Navarro Mt, where it will eventually head south into the canyon Gediz Vallis.
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Update on Ingenuity’s 10th flight and Perseverance’s first sample drilling

3:54 pm

Ingenuity landing at end of 10th flight

The news coming from the Perseverance and Ingeniuty science teams has been sparse this past weekend, even though Perseverance had begun drilling its first core sample that it will stored for pickup by a later unmanned robot, and Ingenuity had attempted its 10th and most challenging flight yet.

We do have images however, and the two to the right give us hints about what has happened.

First, the top picture on the right was taken by Ingenuity’s navigation camera just prior to landing. The camera looks straight down and is used by the helicopter to adjust its flight. The dark area is the helicopter’s shadow. Based on this picture and the four preceding images (taken over an eleven second period), it appears the helicopter was landing safely. No other images have yet been downloaded, nor has the Ingenuity team announced any results, so we do not yet know if the flight proceeded as planned.

UPDATE: The flight was a success, as per this JPL announcement:

With the #MarsHelicopter’s #flight success today, we crossed its 1-mile total distance flown to date. It targeted an area called “Raised Ridges,” named for its #geographic features. Flight 10 is #Ingenuity’s most complex flight profile yet, with 10 distinct waypoints and a new #record height of 40 feet (12 meters).

Drill and core sample in the ground

The second image, taken by Perseverance’s left navigation camera and cropped and reduced to post here, is more puzzling. It shows what appears to be the core sample still in the ground after drilling. While this could be entirely as planned, it seems very surprising. Most of what I can find online describing the operation for obtaining these samples implies that the robot arm would drill the hole, and then retract the sample immediately to place it in storage. Nothing suggests the arm would be retracted with the sample still in the ground.

I think however the odds of this picture revealing a problem are low. This JPL press release from February 2021 implies vaguely that the core sample will be released in this manner before retraction. After the core sample, with bit, is separated from the arm, the release suggests they will lift the arm away to inspect the drilling process, then return the arm to retract the core sample for storage. This does make some sense, though grabbing that sample again will be quite challenging.

If this was not supposed to happen as described, then there is a problem that must be resolved. I expect more details in the next day or so to clarify this situation.

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Ice, lava, quakes, and faults, all in one Martian image

1:04 pm

A lot of geology in one picture
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on April 25, 2021. It grabbed my attention because it possibly captures a whole range of Martian geological processes, all in one place, including evidence of quakes, of lava, of faults, and possibly of glaciers.

First, ignore the black rectangle, which is merely a small section of lost data.

The picture itself shows a wide north-south fissure, as indicated by the distinct western cliff and the fainter and less pronounced eastern cliff. This fissure, likely formed along a fault, was created when the crust was pushed and stretched upward by the pressure of underground volcanic magma, part of the long series of eruptions that formed the many similar and parallel north-south fissures south of the shield volcano Alba Mons.

The overview map below illustrates this fissure’s relationship with Alba Mons.
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Global dust storm on Mars brought on an early spring in southern hemisphere

9:57 am

Scientists analyzing the climate effects from the 2018 global dust storm on Mars have found that while it did little to change the seasons in the northern hemisphere, it caused winter to end early in southern hemisphere.

The team found that the 2018 storm had profoundly different effects in each hemisphere. At the south pole, where the vortex was almost destroyed, temperatures rose and wind speeds fell dramatically. While the vortex may have already been starting to decay due to the onset of spring, the dust storm appears to have had a decisive effect in ending winter early.

The northern polar vortex, by contrast, remained stable and the onset of autumn followed its usual pattern. However, the normally elliptical northern vortex was changed by the storm to become more symmetrical. The researchers link this to the high dust content in the atmosphere suppressing atmospheric waves caused by the extreme topography in the northern hemisphere, which has volcanoes over twice as tall as Mount Everest and craters as deep as terrestrial mountains.

These differences are likely also related to the eccentricity in the Martian orbit around the Sun, which is greater than that of Earth and actually has a direct effect on its seasons. As noted in this recently published paper about the activity scientists have now documented on the Martian surface in the past decade,

Because perihelion (the closest approach to the Sun) currently occurs [during summer in the south], southern hemisphere seasons are more extreme, with a longer winter and shorter, warmer summer

This difference is probably a major factor explaining the different effects of the global dust storm. It also is probably why the Red Planet’s two polar ice caps are so different.

This difference between the two hemispheres will also likely help drive the intitial human settlement on Mars to the north. Not only does the northern hemisphere have the flat lowland plains, making those first difficult landings easier and safer, it has a more benign climate year round.

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Scientists refine Martian interior based on quakes detected by InSight

9:11 am

Martian quake map as seen by InSight

Scientists today published three studies in the journal Science outlining their conclusions about the interior of Mars, based on the quakes that have been detected by InSight since it arrived on Mars in November 2018.

Reporting in a trio of studies published in the July 23rd Science, the Insight science team has now analyzed about 10 marsquakes to make the first direct observations of the structure within another rocky planet. The results — a surprisingly thin crust, an undifferentiated mantle, and a larger-than-expected core — will help determine how Mars formed and evolved.

There results are essentially what was described in April by the InSight science team at the annual 52nd Lunar and Planetary Science Conference (and reported here but no where else), though now more carefully and thoroughly described.

The discovery that the Martian crust is much thinner than expected, either 12 or 24 miles thick, with a core that is still liquid, has ramifications that might help explain both the planet’s formation and its volcanic history and giant volcanoes.

One piece of good engineering news in connection with the lander InSight:

Despite a dust-fueled energy crisis earlier this year, the solar-powered lander has since regained some power-generating capacity. “We are at least safe for this season’s winter and probably far into 2022,” Stähler says.

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The wind-swept volcanic ash plains of Mars

2:19 pm

Overview map

Cool image time! In Mars’ volcano country lies the planet’s largest ash deposit, dubbed the Medusae Fossae Formation. Scientists believe that this gigantic deposit, with a size comparable to the nation of India, was laid down by muliple volcanic eruptions over several billion years and is the source of most of the dust seen on the Red Planet.

The overview map on the right shows the location of this ash deposit on Mars. The white cross indicates the location of today’s cool image, found below.
» Read more

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It’s drill time for Perseverance!

8:18 am

The Perservance science team is preparing the rover for its first drill hole and the first collection of a sample to cache so that a future spacecraft can return it to Earth.

They are presently at the general location where they wish to drill, and are looking for the exact right spot.

The sampling sequence begins with the rover placing everything necessary for sampling within reach of its 7-foot (2-meter) long robotic arm. It will then perform an imagery survey, so NASA’s science team can determine the exact location for taking the first sample, and a separate target site in the same area for “proximity science.”

“The idea is to get valuable data on the rock we are about to sample by finding its geologic twin and performing detailed in-situ analysis,” said science campaign co-lead Vivian Sun, from NASA’s Jet Propulsion Laboratory in Southern California. “On the geologic double, first we use an abrading bit to scrape off the top layers of rock and dust to expose fresh, unweathered surfaces, blow it clean with our Gas Dust Removal Tool, and then get up close and personal with our turret-mounted proximity science instruments SHERLOC, PIXL, and WATSON.”

“After our pre-coring science is complete, we will limit rover tasks for a sol, or a Martian day,” said Sun. “This will allow the rover to fully charge its battery for the events of the following day.”

Sampling day kicks off with the sample-handling arm within the Adaptive Caching Assembly retrieving a sample tube, heating it, and then inserting it into a coring bit. A device called the bit carousel transports the tube and bit to a rotary-percussive drill on Perseverance’s robotic arm, which will then drill the untouched geologic “twin” of the rock studied the previous sol, filling the tube with a core sample roughly the size of a piece of chalk.

Perseverance’s arm will then move the bit-and-tube combination back into bit carousel, which will transfer it back into the Adaptive Caching Assembly, where the sample will be measured for volume, photographed, hermetically sealed, and stored. The next time the sample tube contents are seen, they will be in a clean room facility on Earth, for analysis using scientific instruments much too large to send to Mars.

Not all drill samples will be cached in this manner.

With this press release and press conference NASA continued to push the fiction to the press that Perservance’s prime mission is to search for life. That is a lie designed to catch the interest of ignorant journalists who don’t know anything. The rover’s real mission is to study the overall Martian geology in Jezero Crater in order to better under the planet’s present geology as well as the geological history that made it look like it does today.

If the scientists using Perseverance find evidence of life, wonderful, but that is not their prime goal.

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Another “What the heck?” photo from Mars

1:59 pm

Isolated clump of mounds on Mars
Click for full image.

The cool image to the right, cropped and reduced to post here, was taken a decade ago, on August 25, 2011, by the context camera on Mars Reconnaissance Orbiter (MRO), It shows a flat plain with a sudden clump of mounds or hills at the center.

This is one of those pictures from Mars which I like to call a “What the heck?” image. What caused the mounds, and why are they found only in this concentrated clump, with the rest of the terrain around them generally flat?

Though the context image was taken a decade ago, no follow-up high resolution images were taken of this area until very recently.

Below is the one recent high resolution image taken by MRO on May 12, 2021, cropped and reduced to show the bottom half of the mound clump as shown by the white box. It makes the mystery even more puzzling.
» Read more

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Ice-filled craters in Mars’ glacier country?

1:10 pm

Craters in Protonilus Mensae
Click for full image.

Today’s cool image returns us to the chaos region dubbed Protonilus Mensae, the middle of three adjacent mensae regions in the northern hemisphere that I like to dub Mars’ glacier country because there is so much evidence of buried ice there.

The photo to the right, cropped to post here, was taken on May 31, 2021 by the high resolution camera of Mars Reconnaissance Orbiter (MRO). Titled “Layered Feature in Crater in Protonilus Mensae,” the section I have posted focuses on several craters, with the one with the central mesa likely the picture’s target. Based on many similar features found in craters in this region, it is somewhat safe to assume that this mesa is made of buried ice.

The overview map below as always provides the context.
» Read more

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Cracks, chaos, and maybe caves in one place on Mars

11:34 am

Mosaic of Avernus Cavi fissures
Click for higher resolution. Original images found here and here.

Today’s cool image to the right is a mosaic I have made from two images taken by the context camera on Mars Reconnaissance Orbiter (MRO), showing a most intriguing region on Mars dubbed Avernus Cavi, located in the large volcanic plain called Elysium Planitia between the giant volcanoes Elysium Mons and Olympus Mons, a region I like to call Mars’ volcano country.

The mosaic shows in one picture much of the typical terrain in Avernus Cavi. We see many linear depressions or cracks, created when the ground stretched and cracked at weak points. We also see many depressions that suggest sinkholes, places where the surface sagged down because of a void below ground.

The area of knobs and mesas in the picture’s southeast quadrant is very typical Martian chaos terrain, the later result of long term erosion of these cracks and depressions.

The white box shows the area covered by the image below.
» Read more

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The lacy rocks of Mars

9:36 am

Lacy rocks on Mars
Click for full image.

Cool image time! The image to the right, cropped and reduced to post here, was taken on July 16, 2021 by the Mars rover Curiosity, using its high resolution mast camera.

There isn’t much to say. These are alien rocks, created in a place with a gravity only about a third that of Earth’s in a climate that is very different. Their delicate nature suggests we are looking at something that was once more substantial and has since been undergoing erosion.

Nor has it been that unusual to find rocks so dainty on Mars. In fact, the more Curiosity has climbed, the more such things have been visible. And similar things were seen by the rovers Spirit and Opportunity.

How such rocks formed initially in the far past, under what climate conditions, remains the number one mystery on Mars. What is now causing it to flake away into such a finespun gossamer of complexity is as much a mystery, tied more to the climate and geology of Mars today.

This rock sits on the bottom flank of Mt Sharp in Gale Crater, at the highest elevation Curiosity has yet climbed. At this point the rover has just entered a new geological unit, what scientists have dubbed the sulfate unit. The evidence gathered from a distance (that so far appears confirmed by recent observations) suggest that this unit was formed under a fluctuating environment that laid down many layers of sediment as conditions ebbed and flowed.

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First attempts to map the layered geology of Mars

1:47 pm

layers in Jiji Crater on Mars
Click for full image.

Today’s cool image illustrates well the central task of much of today’s geological research on Mars, using the orbital images to try to map out the visible geological layers seen, and figure out if those layers mark over wide regions specific geological epochs, as they do on Earth.

The photo to the right, cropped and reduced to post here, was taken on May 4, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and featured on July 12th as a captioned image entitled “Layers Blanket a Crater Floor.” From the caption:

This image shows a layered rock formation within Jiji Crater that has eroded into buttes and stair-like layers.

This formation extends west and east. Similar layered rocks are within several craters in Arabia Terra and Meridiani Planum, including [nearby] Sera and Banes craters. The similarities suggest that the same process was forming deposits over a large geographic area long ago. Our image also indicates that much of the formation has eroded away relative to what has remained.

As you can see in the photo, the layers form a neat staircase of terraces descending from the south crater rim to the crater floor. They suggest that once the crater was filled with this material, which over time eroded away.

An image of similar layered buttes and mesas in Sera crater, only about 20 miles away, was featured here on Behind the Black in December 2020 The overview map below shows the relationship between Jiji, Sera, and Banes craters.
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Craters on Ganymede’s striped surface

11:27 am

Craters on Ganymede
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Cool image time! The photo to the right, cropped to post here, is a color enhanced section taken from of one of the images taken by Juno when it did a close fly-by of the Jupiter moon Ganymede back on June 7, 2021.

The enhancement was done by citizen scientist Navaneeth Krishnan, using a wider Juno image of Ganymeded enhanced by citizen scientist Kevin Gill. That wider image is below, and marks the area covered by this first image with a white box.

In this one picture we can see many of the geological mysteries that have puzzled scientists since the Galileo orbiter first took close-up images back in the 1990s. We can see patches of grooved terrain with the grooves in the different patches often oriented differently. We can also see bright and dark patches that while they overlay the grooved terrain they bear no correspondence to those grooved patches. And on top of it all are these small craters, impacts that obviously occurred after the formation of the grooves.
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Clashing layers in Mars’ largest canyon

1:20 pm

Clashing layers on a mountain slope on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on May 27, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows the clash of different layers on the western slope of a mountain within Mars’ largest canyon, Valles Marineris.

The scientist have labeled this a “possible angular unconformity.” In geology an unconformity generally refers to a gap in a series of layers, a period when instead of the layers being deposited they are being eroded away, leaving no record for that time period. An angular unconformity adds tilting to the older layers, which after erosion are then covered by new layers that are oriented somewhat differently.

Based on these definitions, what the scientists suspect is that the brighter layers to the left and lower down the mountain are older. After a period of erosion new layers were deposited on top at a different angle, forming the stripe of layers going from center left up to center right.

The swirly nature of the material on the top of the ridge suggests to me that these layers might be volcanic in nature, but that’s a pure uneducated guess. What some scientists do believe (but have not yet conclusively proven) is that the lower older layers are sediments laid down by an ancient lake that once filled the canyon here.

The overview map below provides a wider view and some context.
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Ingenuity’s view of Jezero Crater during its 9th flight

11:57 am

Ingenuity looks across Jezero Crater
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Overview map
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Cool image time! The photo above, cropped, enhanced, and reduced to post here, was taken on July 5, 2021, about thirty seconds after Ingenuity had taken off on its 9th flight on Mars. I have increased the contrast slightly to bring out the features. This is a raw image, so I do not think the colors are accurate, and I also do not know why the middle of the image is brighter than the edges.

The red lines on the map to the right indicates the general area this image captures. Essentially, once the helicopter reached its flying altitude after liftoff the engineers had it tilt so that it could see the route it was about to take to the southwest. As they noted in their description of this flight,

We began by dipping into what looks like a heavily eroded crater, then continued to descend over sloped and undulating terrain before climbing again to emerge on a flat plain to the southwest.

I think that crater is visible on the left edge of this picture.

So far 180 raw images from Ingenuity have arrived at JPL. There might be a few more, but I think this is the bulk from the flight. Of these, all but nine are black and white and point straight down. The nine color images seem tilted up towards the horizon to various degrees, though the image above is the only one that captures the horizon itself and the distance mountains of Jezero Crater’s rim.

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Curiosity looks across at the alien landscape of Gale Crater

2:25 pm

Curiosity's view across Gale Crater
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Most of the images from Curiosity that I have posted recently have been of the spectacular mountain scenery looking south at Mount Sharp itself. Today’s cool image, taken on July 6, 2021 by the rover’s right navigation camera and cropped to post here, instead looks north, out across the floor of Gale Crater to its distant rim about twenty miles away.

The rover is likely not to move for a week or so, as it has just completed drilling its first drillhole since it moved up into the next geological layer, dubbed the sulfate unit. Because of this they have been using the rover’s cameras to take a lot of pictures of the surrounding terrain, including several high resolution mosaics.

The two overview maps below show what the cool image above is looking at.
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