Tag: Mars

Cryptic Terrain on Mars

1:01 pm

Cryptic terrain near Mars' south polar ice cap
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Cool image time! The photo to the right, rotated and cropped to post here, was taken on September 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what is likely a crater that is partly buried by ice and dust and sand near or on the edge of Mars’s south polar ice cap.

It also shows an example of what planetary scientists have dubbed “cryptic terrain,” found generally on the margins of that ice cap. In this case, the location is on a plateau adjacent to the ice cap dubbed Promethei Planum. Despite a lot of searching, I could not locate any research papers describing Promethei Planum, though data outlined in one Mars Express press release from 2008 suggested it was part of the polar ice cap more than two miles thick that is covered by a thin mantle of dry ice each winter.

The strange curlicue cliffs and plateaus seen here are thought to form as part of the arrival and then sublimation away of that seasonal dry ice mantle, but how that process exactly works to create these particular geological features remains I think a mystery. North is to the top. The general grade is also downhill away from the icecap to the north.

Moreover, the overview map below, with the location of this image indicated by the blue cross, illustrates more mysteries.
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Landslides on the edge of Mars’ youngest lava field

1:52 pm

Landslides on the edge of Mars' youngest lava field
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Cool image time! The photo to the right, cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on September 28, 2020. It shows several indentations in a north-south cliff face, with debris apparently falling down into a flat plain to the east.

The scientific history of this picture is very interesting. The first photo of these landslides was taken in 2006 and was titled, “Landslides on Flat Topography in Elysium Planitia”. The second, taken a few months later in 2007 to produce a stereoscopic view, was labeled “Landslides Along Shoreline in Elysium Planitia.” This most recent 2020 image is merely labeled “Landslides in Elysium Planitia.”

Is the flat terrain to the west a seabed to an ancient ocean, as suggested by the title for the 2007 image, with these landslides erosion caused in the far past by water lapping up against these cliffs?
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Terby Crater and its drainages into Mars’ basement

1:59 pm

Channels in Terby Crater on Mars
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Cool image time! Over the past few years, in my endless rummaging through the archive of high resolution images from Mars Reconnaissance Orbiter (MRO) I have posted a lot of photos of meandering channels of all kinds, most of which evoke to Earth eyes canyons eroded by flowing water. (This September 2020 cool image is just one of the more recent examples.)

Today’s cool image is another example, but in this case it is only a very small part of a very large drainage basin that is more than a hundred miles across and extends at least that far southward into the basement of Mars, Hellas Basin, the place on Mars with the lowest elevation.

The photo to the right, rotated and reduced to post here, was taken on September 12, 2020 by the high resolution camera on MRO. I normally wouldn’t post the whole image, but to crop it would mean you wouldn’t get the sense of extensive nature of this drainage. Downhill is to the south. The channel apparently passes through three or four stages. First, its northernmost section is in a wide canyon, the floor of which resembles glacial debris (though with a latitude of 27 degrees south this is a bit too close to the equator for ice). More likely we are looking at wind-blown sand and dunes being pulled downhill in the floor of the canyon.

This first canyon is also actually a gap in the rim of a 13-mile-wide unnamed crater. See this MRO context camera image for a wider view.

Next, the drainage becomes a series of meandering small interweaving channels, resembling the channels often seen in beach mud as the tide goes out.

Finally, the channels head into a gap to fall over a sloping cliff into lower terrain.

Nor these stages entirely linked. The first glacial-like stage exiting the gap in the crater appears to drain to the southeast, while the second seems to emanate from what appears to be a very faint small crater now partly buried. Both head south toward the gap, but the path of the eastward drainage appears less obvious. Some of it flowed westward to join the meandering channels but some also appears to work its way south more to the east.

This one image shows a lot of channels, but it is only a very small slice of this whole drainage system. In fact, we are looking here at only one strip of the interior slope of the northern rim of 108-mile-wide Terby Crater.

The overview map below gives the larger context. Terby Crater sits on the northern border of Hellas Basin, which in itself extends another 1,500 miles to the south. From this point the drop in elevation into Hellas is almost four miles.
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Ice-filled crater on Mars?

12:13 pm

Crater in southern mid-latitudes
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Time for another of the many cool images from Mars that suggest the presence of buried glacial ice. The photo to the right, rotated, cropped, and reduced to post here, shows an unnamed crater in the cratered southern highlands of Mars at about 44 degrees south latitude. Taken on October 2, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), the crater sits at the very southernmost point of the Tharsis Bulge where the Red Planet’s four more distinctive giant volcanoes are located.

The crater is also in the middle of the 30 to 60 degree mid-latitude bands where scientists have detected many features that suggest glaciers, including a large number of craters that appear to have ice filling their interior.

Does the material in this crater’s floor suggest eroding and sublimating ice to you? It does to me. The second image below zooms in at full resolution at the north-south trench and the strange patterned terrain to its east.
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Aram Chaos: Illustrating the puzzle of Mars

11:20 am

Aram Chaos
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The geological history of Mars is incredibly complex, and we really don’t know much about it. What we do know right now is based on a limited number of tiny fragments of a much larger story, with those fragments allowing scientists to only make educated guesses on how they fit together.

Many of those guesses will certainly turn out right. Just as many will turn out wrong. At this moment in our exploration of the Red Planet we can only grasp at straws while always keeping an open mind, as later data is surely going to change any conclusions we presently have.

The photo to the right is a good illustration of this struggle. Rotated, cropped, and reduced to post here, it was taken on September 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what at first glance looks like a stream of white frost or ice descending down a canyon to the south.

That first impression however is entirely wrong. When I asked Chris Okubo of the U.S. Geological Survey, who requested this image from MRO, what it was, he explained,

The white material is not frost. Instead, these are sedimentary rocks comprised primarily of sulfates. The texture to me suggests these are lithified dunes.

Lithified merely means that the dunes have hardened into rock. Sulfates are a salt formed from sulfuric acid, and are on Mars often linked to some complex mineralogy. If you stood there the colors would be white and red, quite beautiful. As Okubo explained,

The sulfates are white to tan in color, but there would also be a lot of red/brown Mars dust on top of it. It would be similar to walking around some of the playas in the desert southwest.

Though these white sulfate deposits have their root in sulfuric acid, Okubo added that they “are in the form of minerals similar to gypsum and so they would be safe to touch.”

What is going on here? As is usually the case, we need to first take a wider view to get some context.
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Sagging cliffs on Mars

11:20 am

Sagging escarpment on Mars
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Cool image time! On Mars things change, but not like on Earth because the atmosphere is not as thick and there is no flowing water. The photo to the right, rotated, cropped, reduced, and annotated to post here, gives a good example of that slow change. The image was taken on August 29, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows the high escarpment that in this one place separates the planet’s southern cratered highlands from the transition zone down to northern lowland plains.

In this spot that escarpment, approximately 4,000 feet high, shows signs of avalanches and sagging. In the upper steep section, I point to what looks like a dust avalanche that wiped the slope clear of rough terrain as it rolled downhill. At the bottom of the cliff a large section has separated away. Since this cliff is located at 28 degrees north latitude and is in the midst of the chaos terrain regions I like to dub glacier country, it is very possible that this large section is actually buried glacial ice that in shifting down slope cracked, separating the lower section from the upper.

This particular location is east of an area dubbed Nilosyrtis Mensae (where there is a lot of evidence of glaciers and frozen ice), and about 650 miles north of Jezero Crater, where the rover Perseverance will land on February 18, 2021.

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A spray of Martian meteorites

12:27 pm

A spray of small secondary impacts
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on October 26, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is what the camera team calls a “terrain sample,” meaning it was not specifically requested by a researcher but was instead chosen by the camera team because they need to regularly take images to maintain the camera’s temperature. When they do this, they try to pick a location that hasn’t been photographed in high resolution previously, and that might have some interesting features. Sometimes the photo is boring. Sometimes they hit pay dirt.

In this case, the photo captured an small impact crater, about 1,300 feet across, surrounded by a spray of secondary impacts. The color portion of the image shows what I suspect are dust devil tracks cutting across a surface that, because of its blue tint, is either rough or has frost or ice within it. At 48 degrees north latitude, the possibility of the latter is high, especially because this location is northwest of the Erebus mountains, where SpaceX has its prime Starship candidate landing zone and where scientists suspect ice is readily available very close to the surface. The overview map below shows this context.
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A place on Mars where lakes, snowfall, and rivers once existed

2:19 pm

Inverted channels near Juventae Chasma
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Cool image time! The photo to the right, cropped and enhanced to post here, attracted my immediate interest when I was going through the November image dump from Mars Reconnaissance Orbiter (MRO) because of its meandering sharp ridges, estimated to be about sixty feet high on average. While I have previously posted MRO images of inverted channels such as these, their particular sharpness, plus their large number in this localized single image, aroused my curiosity. What is their history? Does this illustrate an particularly interesting place on Mars?

The picture itself was taken was on September 29, 2020 by MRO’s high resolution camera. The blue areas in the color strip probably indicate coarser-grained surface. This makes sense, as these ridges are believed to have been initially carved as channels by flowing water or ice, which compressed their riverbed and thus made it resistant to erosion. Over time, the surrounding terrain eroded away, leaving that channel behind now as a upstanding ridge. The surrounding eroded terrain should thus be expected to be rougher.

Where did the water for these rivers come from, however? As always, the overview maps below give the context, and a possible explanation.
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Eroded and possibly wet Lohse Crater

2:51 pm

Gully flow near central peak of Lohse Crater on Mars
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Cool image time! Today we take a look at one particular 100-mile-wide crater, Lohse Crater, located in the southern cratered highlands on Mars. The photo to the right, cropped and reduced to post here, focuses in on one of the many eroding gullies found in the mountainous region surrounding the crater’s central peak. Taken on August 20, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), the full image is centered on that central peak, just off the south edge of this cropped section. This new image is part of a long monitoring campaign, begun in 2007, of this central peak region. For more than six Martian years, scientists have been tracking the numerous gullies found throughout the central peak region to see if there have been any changes.

I focused on this specific gully because I think it illustrates well why planetary scientists are monitoring these gullies. Whatever flowed down from the cliff on the left hit the material on the right hard enough and fast enough to imprint a curve into the material on the crater floor. Moreover, it does not appear to have simply been a landslide, for several reasons. First, the cliff does not appear cut back at the flow’s head, as you would expect if a section had broken off. Second, the material in the flow does not look like debris from an avalanche. In fact, there does not appear to be very much debris in the gully at all.

Third, and most important, the flow appears to originate at the cliff base, kind of what you’d expect if there was seepage coming out of a layer in that cliff face. Kind of what you’d expect on Earth, at a spring!

Was that flow water? This is the big question. Lohse Crater is significant in that it was one of the first locations on Mars [pdf] spotted by Mars Global Surveyor in the late 1990s where gullies were found suggesting some form of regular erosion possibly caused by flowing water. As this 2005 paper then concluded,
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Giant wind eddies in the sands of Mars

12:13 pm

Wind eddies on Mars
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Cool image time! The image to the right, cropped and reduced to post here, was photographed by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on August 5, 2020. It shows a cluster of the crescent-shaped gullies, apparently carved from desert sand by the prevailing winds.

Those prevailing winds here are from the southwest to the northeast. As the wind blows the sand to the east, it hits a more solid object, such as a mountain buried in the sand, which forces the wind and the blown sand to go around, much as water passes a boulder in river rapids. That solid object also causes an eddy to form at its face, the wind forced downward and then around and up, carving out the gullies by lifting the sand at the base of that solid object. The result are these crescent gullies, dubbed blow-outs.

The overview map helps explain why there is so much sand here, enough apparently to bury whole mountains.
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Glacial eddies on Mars?

12:24 pm

Glacial eddies on Mars?
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on August 15, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a truly strange bunch of blocks beside a clean flow neatly organized in almost straight parallel lines.

What is going on? This location is at 38 degrees south latitude, a latitude where scientists have found a lot of features that resemble water ice glaciers, generally protected from sublimating away by a thin layer of dust and debris.

A first guess is that the smooth glacial flow at the lower right is disturbing the glacial material next to it, causing it to rip apart and break up. At the same time, the hollowed look of these glacial blocks suggests that the ice below that protective debris layer is also slowly sublimating away, causing the surface to sink.

The wider shot below helps confirm this impression.
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Curiosity data suggests the occurrence of mega floods in Gale Crater

3:30 pm

The uncertainty of science: Using Curiosity data a team of scientists are now suggesting that some of the features the rover has seen were created during mega flood within Gale Crater, and this data also requires a rethinking of the present theories of the crater’s geological history.

This case includes the occurrence of giant wave-shaped features in sedimentary layers of Gale crater, often called “megaripples” or antidunes that are about 30-feet high and spaced about 450 feet apart, according to lead author Ezat Heydari, a professor of physics at Jackson State University.

The antidunes are indicative of flowing megafloods at the bottom of Mars’ Gale Crater about 4 billion years ago, which are identical to the features formed by melting ice on Earth about 2 million years ago, Heydari said.

The most likely cause of the Mars flooding was the melting of ice from heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs. The water vapor and release of gases combined to produce a short period of warm and wet conditions on the red planet.

The press release above focuses on the catastrophic floods, but the research paper itself is really much more focused on the need to rethink present hypotheses for explaining the observed geology in Gale Crater. This report notes that they are finding patches of material that could not have been laid down as seen, based on those past theories, and proposes the catastrophic flood event as a possible solution.

In reading the paper however it is evident that even this new hypothesis is based on a limited amount of data, and thus can have holes punched in it as well. This is not to say that the paper is invalid, only that it must be taken with some skepticism. The data being obtained at Gale Crater simply incomplete. Curiosity is following only one path, and has not even left the foothills of Mount Sharp. In order to gain a wider and fuller understanding geologists need to study the entire crater floor, as well as the geology on the mountain.

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Frost on a Martian hillside

3:02 pm

Frost on Martian hillside
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Cool image time! The image to the right, cropped to post here, was taken on August 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a flat-topped mesa in an enclosed canyon dubbed Sisyphi Cavi in the high southern latitudes of Mars during the spring.

Notice the white spots in the gullies on the southern-facing slopes? From what I can gather from a bit of research, these indicate the presence of carbon dioxide frost. It was spring at this location when the photo was taken. At that time, the thin seasonal mantle of dry ice that covers Mars’ the polar regions south to 60 degrees latitude in the winter is sublimating away. This would explain why the frost is only present in the south-facing slopes. Since this is in the southern hemisphere, the south-facing slopes get much less sunlight, and would sublimate away later.

The photo was taken as part of a monitoring program to study this sublimation process. According to this abstract:

Superposition of channel features over and/or through the defrosting CO2 snowpack shows that the channels are active at the present day and probably have fluid flows every spring during the annual defrosting. In itself, this is a significant observation as active fluid flows of any nature have not yet been proven on Mars. However, the ambient temperature at the time of gully activity appears to require a role for CO2 in the formation of the channels, rather than water.

In other words, the coming and going of this dry ice frost each Martian year, in conjunction with the underground water ice also found here, appears to be causing erosion that then creates of the gullies themselves. More details from the abstract in this paper:
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ESA completes new parachute test for its 2022 Mars rover

9:58 pm

On November 9, 2020 the European Space Agency finally conducted the high altitude parachute test of the landing system for its 2022 Mars rover Rosalind Franklin that had been planned for March but had been delayed due to the Wuhan flu panic.

The timeline of the latest test, including extraction and deceleration, went exactly to plan. However, four tears in the canopy of the first main parachute and one in the second main parachute were found after recovery. The damage seemed to happen at the onset of the inflation, with the descent otherwise occurring nominally.

The team are now analysing the test data to determine further improvements for the next tests. Planning is underway for future tests in the first half of next year, to ‘qualify’ the complete parachute system ready for launch in September 2022.

Overall they consider the test a success, though the damage issues must be solved before the ’22 launch. Based on this test it also appears that the ESA made a very wise choice delaying the mission from launch this year, as its parachute system was clearly not ready.

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Buried mountain on Mars

2:17 pm

Isolated buried mountain on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 8, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it is an example of an image taken more for engineering than scientific reasons. No research scientist specifically requested it. Instead, the scientists operating the camera took it because they need to use MRO regularly to maintain the camera’s proper temperature. To do this they periodically take almost random images, but never without trying to pick a location that might have some scientific value.

In this case we get what appears to be an isolated sloping hill. Located at about 15 degrees north latitude, this is not a place where one would expect visible evidence of water, though the gullies on the slopes are intriguing. They almost look like the kind of hillside erosion you see in places where rain falls on desert mountainsides.

Rain can’t be the cause, but nonetheless monitoring these gullies for changes over time would be worthwhile science research. Since it appears no one is presently focused on doing it, anyone interested out there?

This mountain is actually far more isolated than this high resolution image suggests.
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A majestic terraced butte on Mars

1:35 pm

Majestic butte on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on September 8, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an outstanding terraced butte that would rival any of the similar buttes scattered throughout the Grand Canyon, and is reminiscent especially of Wotans Throne.

What makes this butte intriguing are its terraces, the obvious result of the repeated deposition of new layers across the surface over time, and now exposed by erosion. What caused them?

As always, location provides the clues. First, this butte is found at about 15 degrees north latitude in the vast Arabia Terra transition region between the Martian northern lowland plains and the southern cratered highlands. At that latitude, we are not looking at any recent glacial features. While there might have been ice here once, it hasn’t likely been present, either on the surface or underground, for a very long time.

This conclusion becomes important once we look at the wider photo below, taken by the high resolution camera on the European orbiter Mars Express. This image gives us the immediate context.
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MAVEN finds water loss on Mars faster than expected

12:58 pm

New data from the Mars orbiter MAVEN has found that the water on Mars moves into the upper atmosphere where it is lost to space much faster than expected.

It had previously been believed that Mars’ water loss only occurred in the lower atmosphere, which is a much slower process. Scientists had also believed that water on Mars would behave as it does on Earth, where temperatures and the atmosphere act to block it from reaching the upper atmosphere where it can easily and quickly be lost to space. Instead, MAVEN found a lot of water in the upper atmosphere.

When the team extrapolated their findings back 1 billion years, they found that this process can account for the loss of a global ocean about 17 inches deep. “If we took water and spread it evenly over the entire surface of Mars, that ocean of water lost to space due to the new process we describe would be over 17 inches deep,” Stone said. “An additional 6.7 inches would be lost due solely to the effects of global dust storms.”

During global dust storms, 20 times more water can be transported to the upper atmosphere. For example, one global dust storm lasting 45 days releases the same amount of water to space as Mars would lose during a calm Martian year, or 687 Earth days.

This data reinforces the theories that Mars once had liquid water on its surface, either as intermittent oceans or as lakes and rivers. Or it suggests that Mars once had a lot more glaciers than it does now, reinforcing a competing theory that glaciers formed the Martian features we on Earth routinely associate with flowing water.

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A field of Martian knobs

12:30 pm

Knob field on Mars
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on August 9, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Uncaptioned, the image is merely dubbed a “knob field.”

I won’t spend much time trying to explain this geology. It might be related to pedestal craters, but these ridges and mesas don’t really look like those features, since they don’t really stand above the surrounding terrain.

Maybe they are a very ancient field of craters long buried, now partly exposed due to erosion, but also partly buried by wind-blown Martian sand and dust. Once again, that many of their shapes don’t resemble craters discounts this explanation.

The location of this photo is in the southern cratered highlands, as shown by the black cross in the overview map below.
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Rover update: Curiosity on the move again

1:51 pm

After spending more than three months at a single site, drilling three different holes in the same rock, Curiosity is finally on the move again, heading east and uphill toward Mt. Sharp. Yutu-2 meanwhile continues its very slow journey on the far side of the Moon. And the new rovers are halfway to Mars.

Drill holes at Mary Anning site in Gale Crater
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Curiosity

The image to the right, cropped and annotated to post here, shows the three drill holes that scientists had Curiosity drill in this one pavement rock, dubbed Mary Anning and located in the clay unit within Gale Crater on Mars. As I noted in my last update on July 22, 2020, the rover’s science team had made a specific detour in their planned route up Mt. Sharp in order to find this one last place to drill in this geological unit.

Though they have been very quiet about their results, apparently what they found in this one pavement rock was important enough that it required three drill holes. In addition, samples from the second hole were subjected to two of Curiosity’s limited supply of wet chemistry experiments. From the science team’s August 28, 2020 update:
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Terraced mesa inside Martian depression

1:14 pm

Terraced mesa inside depression
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on July 1, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a very puzzling terraced mesa inside an enclosed depression or sinkhole (the western half of which can be seen in the full image).

What caused that mesa? A first scan of the image and the data suggests we are looking at sinkage related to the melting of an underground ice table. The latitude here is 34 degrees south, just far enough away from the equator for glacial activity to be possible. Moreover, the small circular depression in the upper right of the image strongly suggests an impact crater into slushy material. The implication is that this depression is the result of the melting or sublimation of underground ice, leaving behind a mesa that is made of solider stuff.

Another possibility is that the terraced mesa is actually the remains of glacial material. In the full image features inside other nearby depressions are terraced also, but are also much more reminiscent of glacial features found in many craters in the mid-latitudes. The depression is also close to the headwaters of Reull Valles, a meandering canyon where many images have shown glacial features (see for example here, here, and here).

These features however could also have nothing to do with water ice.
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Why Martian mountains are different than on Earth

3:08 pm

A mountain peak on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 12, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what to any Earthling’s eye appears to be a somewhat ordinary flat-topped mountain peak with two major flanking ridgelines descending downward to the north and the south, and two minor ridgelines descending to the northwest and southwest.

This peak and its landscape would surely be quite a spectacularly place to visit, should humans ever settle Mars and begin doing sightseeing hikes across its more interesting terrain. I can definitely imagine hiking trails coming up the two minor ridges, with a crest trail traversing the main north-south ridge across the peak.

This is not however a mountain on Earth. It is on Mars, which makes its formation and evolution over time fundamentally different than anything we find on Earth, despite its familiar look.

First, what formed it? Unlike most of Earth’s major mountain chains, the mountains of Mars were not formed by the collision of tectonic plates, squeezing the crust upward. Mars does not have plate tectonics. Most of its mountains formed either from the rise of volcanoes at single hot spots, or from the wearing away of the surrounding terrain to leave behind a peak or mesa.
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Layered mesa on Mars

2:41 pm

Layered mesa on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 24, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a distinctive mesa in a mountainous region in the cratered highlands of Mars, just north of Hellas Basin, the deepest basin on the red planet.

The mesa’s most distinctive feature are its terraced layers, a feature that MRO has found in numerous other places surrounding and inside Hellas Basin (see for example the cool images here, here, here, here, here, and here.)

On Earth the assumption would be that these terraced layers imply different sedimentary layers that erode at different rates, as best illustrated by the Grand Canyon in Arizona. On Mars that assumption is not unreasonable, but unlike Earth, those layers could not have been formed in connection with large ocean bodies creating seafloor layers from the deposit of sealife over centuries. Some other geological process over time formed them, with volcanism, either from volcanoes or impact, being the most likely.
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A buried crater on Mars

3:35 pm

Close overview map

The overview map to the left indicates the general terrain surrounded today’s cool image. The white rectangle is the area covered by this image, taken on July 4, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. If you look close you can see that this photograph covers the eastern rim of what looks like an ancient and mostly buried crater on Mars. This unnamed crater is about 17 miles across.
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Is this the planned landing site of China’s Mars rover?

7:21 am

The prime landing site for China's Mars rover?

According to this Space News article, a report in the Chinese press, since revised to remove the information, had provided precise coordinates on Mars for the prime candidate landing site for China’s Tianwen-1 rover.

[I]nformation published in an article (in Chinese) in the official China Space News publication following launch in July provides a specific primary landing site. The article reported landing coordinates of 110.318 degrees east longitude and 24.748 degrees north latitude, within the southern portion of Utopia Planitia. Online versions of the article have since been edited to remove the coordinates; however, these remain published by sources citing the article.

The mosaic on the right, made up of two images taken by Mars Reconnaissance Orbiter’s (MRO) context camera (found here and here) shows this location with the white cross. The white box is the area covered by the only image taken of this area by MRO’s high resolution camera.

As these photos show, this location, in a part of Mars’ northern lowland plains dubbed Utopia Planitia, is generally smooth and flat, making for a relatively safe landing site. At the same time, it has craters and some ridges and hills that could pose issues.

That the coordinates were removed from the Chinese press story suggests that this might be the prime site, but until Tianwen-1 gets into Mars orbit and begins scouting the site with its own high resolution images, they want to reserve judgement. The spacecraft arrives in orbit in February ’21, and they presently plan to land the rover in May. That gives them three months to scout this location as well as a secondary landing site on the other side of Mars, in the Chryse Planitia northern lowlands [pdf], the same region where Viking 1 and Mars Pathfinder landed.

Once they have done this they will be able to refine the location more precisely.

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Bringing life to the slumping lifeless slopes of Mars

12:05 pm

Slumping slopes on Mars
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To me, the cool image to the right, cropped and reduced to post here, helps illustrate the most significant difference between Mars and Earth, its obvious lack of life. This lack fundamentally changes the nature of erosion on the Red Planet.

On Earth life covers practically every square foot of the surface, and that life probably does more than anything to reshape the surface, and it does it far more quickly than any geological or meteorological process. For example, even if we are in the most lifeless area of the Sahara Desert, with no plant life, the dunes will still be reshaped and changed simply by the passage of any animal, whether it be a lizard, camel, or human driving a jeep.

On Mars, there is no visible life, and this lack means that any changes we see are solely geological or meteorological in nature. From a scientist’s perspective, the view is clean, all changes wrought solely by inanimate nature, without the added factor of life.

In a sense, Mars gives us a view of what geological and meteorological processes would do on Earth, if the Earth was lifeless.

Today’s image, taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on August 29, 2020, exemplifies this. Labeled “Slope Failures in Tempe Terra,” it shows the slow break-up and slumping of debris as it oh-so-slowly falls from higher terrain. The cracks developed as large chunks pulled apart as the material slide downward to the east.

This cracking took a lot of time. On Earth, during that time it would have either been obscured by plant life, or would have been distorted greatly by the traffic of animal life across its surface. Animals would have dug holes, and humans might have reshaped it to build homes and roads. On Mars, none of that happened, so the geology was free to evolve slowly, without interference, and now sits in plain view for scientists to interpret.

Such knowledge will over time strengthen our understanding of Earth geology, because it will give us a better understanding of the influences of life on that geology. Geologists will be better able to separate the influence of life and inanimate natural processes.

The overview map below helps give the wider context of those Martian inanimate natural processes, on a grand planetary scale.
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“Flow-like” feature in the Martian lowlands

1:51 pm


Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and brightness-enhanced to post here, was taken on July 6, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

This is an uncaptioned image, labeled by the MRO science team as a “Flow-Like Feature in Chryse Planitia,” suggesting that they themselves are not exactly sure about what we are looking at. The latitude is 19 degrees north, which is a bit too far south for finding glacial features. Moreover, the craggy look of the ground here does not suggest an eroding glacier, but of eroding bedrock.

We could be looking at a volcanic feature, but this location is very far from Mars’ volcano regions. Nonetheless, another high resolution image, taken just to the west of this photo and given the exact same label, shows similar geology, and does strongly invoke a look of corroded lava flow.

The overview map below gives the context.
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India’s Mars orbiter confirms global dust storms speeds atmosphere loss

9:54 am

India’s Mars orbiter Mission (MOM) has confirmed that the periodic Martian global dust storms act to accelerate the loss of the red planet’s atmosphere.

The U.S. orbiter MAVEN found the same thing during the 2018 global dust storm. Moreover, the two orbiters focused on observing different hemispheres (MOM in the morning and MAVEN in the evening), and bot got comparable results.

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Was there a catastrophic flood in Kasei Valles on Mars?

1:45 pm

Overview map of lower section of Kasei Valles

Figure from paper

In our on-going exploration of Mars using the amazing high resolutions being taken by Mars Reconnaissance Orbiter (MRO), we return today to Kasei Valles, the drainage valley coming down from Mars’ giant volcanoes that I featured only a few days ago. And like that post, we must begin from afar and zoom in to understand what we are seeing in the final cool image.

Kasei Valles is a canyon system is about 1,900 miles long, and would cover two-thirds of the continental United States if placed on Earth. Its north-trending upstream section to the west and south of the area shown on the overview map to the right is thought to have been formed by some combination of glacial and volcanic processes. The downstream west-east section shown in the map instead appears to have been formed by a sudden catastrophic flood, which some scientists have theorized [pdf] occurred when a three hundred long ice dam broke suddenly, releasing the flood quickly across this terrain to create its features. The second map to the right, from their paper, illustrates this hypothesized event.

The white box in 60-mile wide Sharonov Crater near the center of the first map above indicates the location of today’s cool image below. The 1976 landing site of VIking 1 about 420 miles to the east is also indicated.

If you look closely at the first overview map above you can see that the rim of Sharonov Crater appears breached in its southwest quadrant, just to the west of the white box. This breach is less a break and more an area of increased erosion. Regardless, it sure appears that a massive flow pushed through the rim here.
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The edge of Martian chaos

2:05 pm

Overview map of end of Kasei Valles

For today’s cool image, we are going to start from afar and zoom in, because I think that might be the best way to gain at least a rudimentary understanding of the strange geology visible at this one particular Martian location.

The first image, to the right, is the overview map. The red cross indicates our target, a chaotic canyon that flows into the larger Kasai Valles, one of Mars’ largest and longest canyons and possibly only exceeded in size by Valles Marineris. This part of Kasai is near its end, where it drains out into the vast northern lowland plains of Mars.

The second image, below, comes from the wide angle camera on Mars Reconnaissance Orbiter (MRO).
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Update on InSight’s mole: It is now underground

9:29 am

InSight's mole now completely buried
Click for full image.

An update today on the mole digging tool on the Mars lander InSight has revealed that the mole appears to finally be completely buried, though it remains unclear whether its most recent digging effort had succeeded in digging downward.

We found that during the first two rounds of hammering and during the first half of the third round of hammering, the scoop went further into the sand. Since the Mole was hidden under the scoop, the penetration of the probe itself could not be observed directly.

During the hammering, the flat tether running to the probe moved considerably, but these could only be clearly identified as forward movements during the hammering on 22 August. Overall, we could estimate from the movements of the scoop that the Mole moved at most one centimetre further into the ground. It was interesting to observe that during the second half of the round of 250 hammer blows on 19 September, the scoop did not go any further, probably because it encountered duricrust. This was certainly a desired outcome, as it allowed a second Free Mole Test to be conducted. In fact, the probe continued to move according to the movements of the tether, but it could not be clearly determined that these movements brought the Mole deeper into the ground.

The image shows InSight’s arm above the filled hole, with the mole’s flat tether coming out of the ground.

They are now going to fill the hole more, and then press down with the scoop during later drilling efforts to see if this allows the mole to proceed downward. If it fails I’m not sure if there is anything else they will be able to do to get the mole to work.

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