Tag: Mars

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


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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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