Tag: geology

Chang’e-5 samples suggest lunar meteorite impacts took place the same time as big Chicxulub impact

10:23 am

In analyzing lunar samples brought back by China’s Chang’e-5 Moon lander, Australian scientists have found evidence of lunar meteorite impacts that apparently took place the same time as big Chicxulub impact in the Yucatan 66 million years ago, thought by many scientists to have caused the extinction of the dinosaurs.

Their findings suggest that the frequency of meteorite impacts on the Moon may have been mirrored on Earth, and that major impact events on Earth were not stand-alone events and instead were accompanies by a series of smaller impacts. The study has been published in Science Advances.

“We combined a wide range of microscopic analytical techniques, numerical modelling, and geological surveys to determine how these microscopic glass beads from the Moon were formed and when,” says lead author Professor Alexander Nemchin, from the Space Science and Technology Centre (SSTC) in the School of Earth and Planetary Sciences at Curtin University in Perth.

The data suggests two possibilities, neither of which is confirmed. First, the impacts could have occurred because a cluster of large objects hit both Earth and the Moon at the same time. Second, the impacts on the Moon could have been caused by objects thrown up from the Earth when the bigger impact occurred at Chicxulub.

Either way, the data suggests a greater and more complex interaction between events on the Earth and events on the Moon.

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More glaciers in Mars’ glacier country

2:24 pm

Overview map

glacial layering in Clasia Vallis
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 18, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what appear to be layered glacial features on the floor of what at first glance appears to be a crater.

It is not a crater however. The depression in the lower right of this image is the rim and floor of a 77-mile-long meandering canyon on Mars dubbed Clasia Vallis. The red cross in the overview map above marks its location, at 34 degrees north latitude. This channel drains downward from the southern cratered highlands into the 2,000-mile-long mid-latitude strip of mensae terrain that I dub glacier country because almost every hi-res image from this region shows glacial features.

Below is a wider view of Clasia Vallis, taken by the context camera on MRO on March 19, 2014.
» Read more

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Zig-zag ridges on Mars

2:26 pm

Zig-zag ridges on Mars
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on April 9, 2022v by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a series of parallel zig-zag ridges in a flat, knobby terrain.

I don’t presume to explain this at all. According to one research paper,

This interplana region consists of extensive networks of ridges—the eponymous Aeolis Dorsa—and is interpreted as having formed by topographic inversion of fluvial and alluvial deposits.

Why these ridges zig-zag however does not seem to fit into either a fluvial or alluvial explanation, both of which involve the flow of water. The quote implies these could be inverted stream channels (where the compacted streambed becomes a ridge when the surrounding terrain erodes away), but once again, the distinct zig-zag pattern seems wrong. Rivers meander, but they don’t generally turn right and left so sharply. And why should we see parallel zig-zags? This doesn’t seem to fit with a river channel origin.

The particular location, as shown on the overview map below, is close to the dry Martian equator, on the edge of Medusae Fossae Formation, the largest field of volcanic ash dust on Mars.
» Read more

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Above ground and underground Martian drainages

2:28 pm

Overview map

Cool image time! Today we are going to zoom into our cool image. The overview map to the right provides us the context. Our target is the small white rectangle inside the small box just below the north rim of 185-mile-wide Newton Crater, located 200 to 800 miles from the southwest edge of the lava plains dubbed Daedalia Planum that flowed down from Mars’s biggest volcanoes.

Newton Crater has a number of interesting features. Only two weeks ago I featured 4-mile-wide Avire Crater in Newton’s western quadrant, long known to have many gullies on its interior slopes as well as glacier features on its floor. Scientists have been monitoring those gullies now for more than a decade to see if they change seasonally, in a attempt to figure out their cause.

Today’s cool image looks at the very intriguing meandering canyons that appear to flow south from Newton’s north rim.
» Read more

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Watching DART impact asteroid on September 26, 2022

9:35 am

A NASA planetary probe, dubbed DART, is on course for a planned impact of the asteroid Dimorphos this coming Monday, September 26, 2022, at 4:14 PM (Pacific).

DART was launched from Vandenberg Space Force Base, CA on November 23, 2021 PST (November 24 EST) headed to the asteroid Didymos and its tiny moon Dimorphos 7 million miles away. The plan is for DART to ram itself into Dimorphos while scientists on Earth measure whether its orbit around Didymos changes.

Dimorphos is about 525 feet in diameter, while Didymos is much larger, about a half mile in width. The goal is to see if this method can be used in the future to adjust an asteroid’s orbit enough to shift it away from hitting the Earth.

The impact will be observed by a camera on DART, as well as an Italian cubesat dubbed LICIACube.

NASA TV will be live streaming the event, and I will embed that live stream here when it goes live. Once DART gets close, its camera will record the asteroid’s approach through impact.

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Martian layers everywhere!

1:38 pm

Layers in Argyre Basin
Click for full image.

Cool image time! The photo to the left, rotated, cropped, and reduced to post here, was taken on June 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the rim edge to a fifteen-mile-wide canyon, with many apparent layers exposed on the high plateau.

The layers are intriguing in that they suggest several things. First, they give us a glimpse into the top and youngest layers that make up the interior canyon wall. Second, they tell us that erosion has removed much of those top and youngest layers, resulting in the mesas on that plateau.

Finally, the gullies flowing down into the canyon indicate further erosion processes, eating away at the canyon wall over time.

The location of this canyon is also intriguing.
» Read more

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Another model attempts to show how liquid water could have once existed on Mars

11:07 am

The uncertainty of science: Scientists today published a new model that attempts to show how it was possible in the distant past for liquid water to have existed on the surface of Mars.

New research published in Earth and Planetary Science Letters suggests that Mars was born wet, with a dense atmosphere allowing warm-to-hot oceans for millions of years. To reach this conclusion, researchers developed the first model of the evolution of the Martian atmosphere that links the high temperatures associated with Mars’s formation in a molten state through to the formation of the first oceans and atmosphere. This model shows that — as on the modern Earth — water vapor in the Martian atmosphere was concentrated in the lower atmosphere and that the upper atmosphere of Mars was “dry” because the water vapor would condense out as clouds at lower levels in the atmosphere. Molecular hydrogen (H2), by contrast, did not condense and was transported to the upper atmosphere of Mars, where it was lost to space. This conclusion – that water vapor condensed and was retained on early Mars whereas molecular hydrogen did not condense and escaped – allows the model to be linked directly to measurements made by spacecraft, specifically, the Mars Science Laboratory rover Curiosity.

As a model, this theory proves nothing, though it is very intriguing. The scientists propose that the heat from the planet’s interior replaces the known lack of energy that came from the Sun in Mars’ far past. While this could work, what makes it very uncertain is that its surface data is based on a single measurement from Curiosity, hardly a deep and convincing baseline.

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Want to do a virtual hike in Jezero Crater on Mars? You can!

10:01 am

Using data from Mars orbiters, Perseverance, and Ingenuity, scientists have now created a virtual hiking map of Jezero Crater, allowing anyone to explore in detail the same places that the rover and helicopter have visited.

You can view the map here. From the press release:

The map allows virtual hikers to zoom in and out, and pan rapidly across scenes, so that they can explore the landscape from large scales down to centimetre-detail. Some of the 360° panoramas integrated with the waypoints have been synthetically rendered from orbital image data. Others are real panoramas stitched together from a multitude of single images taken by the Mastcam-Z camera instrument onboard the Mars 2020 Rover Perseverance, which have been provided by the University of Arizona. The sounds have been recorded by the SuperCam instrument on that same rover mission.

I’ve played with the map only a little, but find it quite amazing and useful, especially because it seems to work well on my relatively ordinary desktop Linux computer.

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InSight’s power level holding steady

9:57 pm

InSight's on-going power levels

The Energizer bunny of Mars, the InSight lander, continues to hold on. The engineering team tonight issued another status report, as shown in the graph to the right. For the past week the lander continued to produce 420 watt-hours per day, even though the tau level of dust in the atmosphere increased from 0.8 to 0.85.

The tau level of dust outside of the winter dust season is normally between 0.6 and 0.7. Even though Mars is moving out of winter, that level has increased slightly above InSight. And yet, even with a higher dust content and thus less sunlight, the lander’s dust-covered solar panels are generating power, at a very slightly higher level.

The InSight team had expected the lander to die in early September, at the latest. Instead, it keeps running, thus allowing it to detect on September 5th an impact created by a cluster of three asteroids, the first time scientists have ever pinpointed exactly when such a new impact occurred on Mars.

For the lander to survive for even longer, all it needs is one gust of wind across the solar panels to clean them off. The science team had expected this to happen periodically, based on past experience with the Spirit and Opportunity rovers. Unfortunately for InSight, it has not yet happened even once since it arrived on Mars in 2018. Nonetheless, it only has to happen once to save the lander.

Stay tuned. All is not yet lost.

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The strange scattered rocks of Gediz Vallis on Mars

10:28 am

The strange rocks of Gediz Vallis
Click for full image.

Cool image time! The photo to the right, reduced to post here, was taken on August 20, 2022 by Curiosity’s high resolution camera. It shows some of the scattered and very delicate rocks that it is finding on the floor of Gediz Vallis, the valley the rover had been striving for since landing more than a decade ago and finally entered in mid-August.

Because of Mars weak gravity, about 39% of Earth’s, and very thin atmosphere, about 1% of Earth’s, it is possible for surface rocks to erode into such delicate shapes. The shapes appear to be further encouraged by the many layers that exist in Mars, with each layer having different characteristics. In the case of the hanging flakes to the right, these layers were more resistant to erosion and thus remains intact while material above and below was slowly blown away.

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InSight’s seismometer detects its first new impact on Mars

1:13 pm

Martian impact discovered by InSight
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Using data from InSight’s seismometer that suggested a new impact had occurred at a specific location on September 5, 2022 on Mars, scientists used the high resolution camera on Mars Reconnaissance Orbiter (MRO) to search and find that impact.

The photo to the right, reduced to post here, is that MRO photo.

The initial impact itself created a small marsquake that was detected by InSight’s seismometer. The instrument recorded seismological data that showed the moment the meteoroid entered Mars’ atmosphere, its explosion into pieces in the atmosphere, and finally, the impact that created a series of at least three craters in the surface.

MRO then flew over the approximate site where the impact was “felt” to look for darkened patches of ground using its Context Camera. After finding this location, HiRISE captured the scene in color. The ground is not actually blue; this enhanced-color image highlights certain hues in the scene to make details more visible to the human eye – in this case, dust and soil disturbed by the impact.

This was thus the first new Martian impact detected based on its actual occurrence, rather than simply finding a change between two photos taken at different times. The latter only tells you a time period when the impact occurred. InSight’s detection here marks the impact’s exact moment.

Nor is this the only such discovery. It appears that InSight detected at least two other impacts (here and here), that only subsequently were linked to MRO impacts. In those cases, the new impact had already been found by MRO, and only afterward were scientists able to identify its seismic vibration in InSight data, thus pinpointing the exact date it took place.

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Deep inside the youngest flood lava event on Mars

1:30 pm

Deep inside the youngest flood lava event on Mars
Click for full image.

Cool image time! Today we return to the Athabasca Valles flood lava event, believed to be the youngest major lava event on Mars that I highlighted in a cool image last week.

Then, I showed two meandering lava flows near the edge of this Great Britain-sized flood lava plain, produced 600 million years ago in only a matter of weeks. Today, we take a look deep within the lava plain. The photo to the right, rotated, cropped, and reduced to post here, was taken on May 6, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “a lava-crater interaction.”

In plain English, we are looking at a crater that has been inundated by the flood lava, filling it.
» Read more

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The shattered cliffs of Mount Sharp

11:04 am

A broken cliff on Mars

Cool image time! The picture above was taken on August 11, 2022 by the left navigation camera on the Mars rover Curiosity. It shows a great example of the strange manner in which the bedrock in the layered cliffs on Mount Sharp appear to break apart.

I am not certain exactly where this feature is, or its exact scale, but based on the date and where Curiosity was located when the photo was taken, it likely is a small section from one of two hills, Deepdale and Bolivar, that Curiosity passed between in mid-August. It is likely somewhere in the panorama included in my August 11th post, but I have not yet been able to locate it.

Nonetheless, the breakage here is typical of these cliff faces. The structural strength of these layered hills is not very high, so at some point one section can break away from another as the hill sags downward to the left. What makes the cracks here more intriguing is that something caused the higher sections surrounding the main block to widen. On Earth we would assume that this widening was caused by rainwater pouring in from the top. On Mars, that explanation doesn’t hold water.

Wind? Seasonal thermal changes? Neither explains the change in the width of the cracks along their length. Maybe the wider cracks indicate an increased sagging of the hill to the left. The layers below this broken block have simply not slid to the left as much.

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InSight’s power levels rise again

10:16 pm

InSight's power levels through September 10th

Based on another status update issued today by the InSight science team, the electricity generated by the Mars lander’s dust-covered solar panels increased again slightly in the past week, going from 410 watt-hours per day to 420 watt-hours per day.

The graph to the right shows the trends since May. The science team had expected the power levels to steadily drop throughout the summer so that by early September the lander would die.

Instead, the power levels remained steady throughout the summer, and have in the past two weeks actually risen slightly, thus extending InSight’s life.

If at any moment a strong gust of wind or dust devil sweeps over InSight, the panels could be blown clear and it would gain a rebirth. The longer it manages to survive, the greater the chance that this might happen.

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InSight’s power level goes up!

5:54 pm

InSight's power levels as of September 5, 2022

The most recent status update on the Mars lander InSight, released today, shows a slight rise in the amount of power generated by its dust-covered solar panels.

As shown on the graph to the right, on August 27, 2022 the power level was 400 watt-hours generated per Martian day. On September, 5, 2022, the power level was 410 watt-hours per Martian day, the first power increase since late July. At the same time, the dust in the atmosphere continued to clear, going from a tau level of .88 to 0.8. Outside of the winter dust season tau is usually between 0.6 and 0.7.

The slight power increase continues to suggest that the lander’s death might be delayed. At 400 watt-hours per day, it has been able to run its seismometer since the beginning of July. With this slight increase, the chance increases that InSight will finally get that one gust of wind or dust devil that will blow the dust off its solar panels and allow it to recover some power and operate for longer.

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Crazy badlands in the equatorial region of Mars

2:49 pm

Badlands in the equatorial regions of Mars
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Cool image time! The photo to the right, rotated and cropped to post here, was taken on June 17, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The section highlighted is at full resolution, in order to make clear the absolutely crazy and complex terrain seen in the full image.

This terrain is not glacial, as the location is only about 1 degree south of the Martian equator. There might have been surface or near surface ice here once in the past, but there is none now.

Could we be looking at some form of lava flow? This is possible, because a close look at the context map at the image link suggests this region has been partly covered by some material, obscuring some craters to the east and west. However, there is no visible evidence anywhere in this region of a volcanic vent or caldera. If this covering material was volcanic it is very unclear where it came from.

The overview map below does not really provide any answers, but at least gives the context.
» Read more

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A “what the heck?!” mesa in the southern polar regions of Mars

4:49 pm

A
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label a “Circular and Banded Landform.”

I put this mesa into a geological category I dub “What the heck?!” We are clearly looking at a mesa, probably no more than 200 feet high, if that. What makes it baffling are the parallel bands that not only cut across the mesa but extend in the same direction for many miles in all directions. Though at first glance these bands appear to be dunes, their rocky eroded look along the mesa’s northwest rim suggests instead the bands are the top edge of many vertically oriented parallel layers, which at this mesa’s flanks are eroding alternatively at different rates.

The overview map below shows us where this mesa is located, relative to the south pole.
» Read more

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An example of the youngest big lava flow on Mars

1:34 pm

An example of the youngest big lava flow on Mars
Click for full image.

Overview map

Cool image time! The photo above, rotated, cropped, and reduced to post here, was taken on May 13, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows two dramatic ancient flows of flood lava. The arrows indicate what I think is the direction of flow for each, though the direction of the flow to the north appears more certain. In a wider context camera image the bulk of the evidence suggests the southern flow is heading west (as indicated by the arrow), but there are scalloped mesas within it that suggest the opposite.

The overview map above marks the location of this picture by the white cross inside the Athabasca Valles flood lava, thought by some scientists [pdf] to be Mars’ youngest major lava event that erupted about 600 million years ago and in just a matter of a few weeks poured out enough lava to cover an area about the size of Great Britain.

The general trend of the Athabasca flow was to the south, splitting into a big western and southeastern flows. This picture captures the southern edge of that southeastern flow, which might help explain why the flow directions in the picture seem so different from the main Athabasca flow. On a large scale, the flow was to the southeast. On a small scale at the edges the flow could go in many directions as the lava looks to find its level.

The Medusa Fossae Formation is the largest volcanic ash deposit on Mars, and is thought to be the source of most of the red planet’s dust. Though the origin of the ash is not yet known, it likely came from the eruptions that formed the planet’s giant volcanoes to the east and west.

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Computer model: Glaciers move slower in Mars’ gravity

10:00 am

Using a computer model that compared glacier flows on Earth and Mars, scientists have concluded that past glaciers on Mars flowed more slowly than on Earth, and produced different types of erosion features that might explain the red planet’s many riverlike geological features.

The new study modeled how Mars’ low gravity would affect the feedback between how fast an ice sheet slides and how water drains below the ice, finding under-ice channels would be likely to form and persist. Fast water drainage would increase friction at the interface of rock and ice. This means ice sheets on Mars likely moved, and eroded the ground under them, at exceedingly slow rates, even when water accumulated under the ice, the authors said.

From the paper [pdf]:

We show quantitatively that the lower surface gravity on Mars should alter the behavior of wet-based ice masses by modifying the subglacial drainage system, making efficient, channelized drainage beneath Martian ice both more likely to form and more resilient to closure. Using as an example the case of the ancient southern circumpolar ice sheet, we demonstrate that the expected finger-print of wet-based Martian ice sheets is networks of subglacial channels and eskers, consistent with the occur-rence of valley networks and inverted ridges found on the Martian highlands.

This paper confirms the sense I have gotten from the planetary community about glaciers on Mars, that it could be the flow of glaciers that formed its many meandering canyons, not liquid water. The case however is not yet proven, as this is only a computer model.

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Gullies and glaciers in a crater on Mars

4:46 pm

The gullies and glaciers in Avire Crater
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the floor of 4-mile-wide Avire Crater, located at about 41 degrees south latitude inside the much larger 185-mile wide Newton Crater.

This picture was taken as part of a long term monitoring program of the many gullies that flow down the slopes of the crater’s interior rim. In fact, the gullies of this crater have so interested scientists that one even proposed [pdf] this location as a potential future rover landing site.

Avire Crater, a small … gullied crater within Newton Crater, provides many aspects ideal to a future rover mission. It has been previously hypothesized to be the location of a former paleolake with multiple episodes of ponding and deposition. Gullies occur almost continuously on the southwest wall clockwise to the northeastern wall. Dark-toned dunes are present in the northern portion of the crater, in some places obscuring gullies while cut by gullies in others. No changes in the extent or appearance of the dunes have been observed since they were first imaged … in January of 2000. The dunes lack superimposed craters, indicating that the gullies that cut through them are geologically very youthful. Layered lobate features are present at the base of the gullies on the northern wall, seen in many other craters on Mars (not always in association with gullies), which have been suggested to have formed as terminal moraines of ice-rich flows; in Avire, these features have also been suggested to be paleolake deposits. The crater floor is obscured by mid-latitude “fill” material, hypothesized to be partially comprised of ice based on morphologic evidence that the material has been partially removed.

As gullies, dunes, and “fill” material occur in many places on Mars, a single rover mission to a site containing these features would provide valuable information applicable to thousands of other locations across the planet.

The curved ridgeline in the crater floor is thought to be a moraine. The “fill” material to the south is essentially glacial in nature. Both, as well as the gullies, appear to have been shaped either a paleolake that once existed in the crater or by cyclical glacier activity. By going to this one crater, scientists could study all these different geological features at one time.
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Ingenuity’s flight plan for its next and 31st flight

10:22 am

Perseverance's location on September 2, 2022
Click for interactive map

The Ingenuity engineering team today released the flight plan for the helicopter’s next flight on Mars, its thirty-first since arrival.

The flight is scheduled for no earlier than September 6, mid-day on Mars, and will travel about one minute to the west for a distance of about 319 feet. The white dot on the overview map to the right shows the approximate landing spot, with the green dot marking Ingenuity’s present position. The blue dot marks Perseverance’s present position as it moves to the south and west after leaving the first delta cliff face it studied during the past few months.

The flight’s main goal is to reposition the helicopter to keep it close to the rover to facilitate communications. However, the engineering team has also now adjusted its goals to also practice hitting very precise landing spots. This goal is to develop the engineering and software that can be used on the helicopter that is not yet built that NASA and ESA intend to use to recover Perseverance’s core samples for return to Earth. That helicopter will not only have to very precisely land right next to those samples in a position allowing it to grab them, it must also land very precisely next to the sample return spacecraft to deposit them within it.

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On Mars you can find glaciers everywhere in the mid-latitudes

12:42 pm

Glacial material in Mars' rift zone
Click for full image.

Cool image time! If you ever decide to have some fun exploring the archive of images being sent back to Earth by the high resolution camera on Mars Reconnaissance Orbiter (MRO), always remember that the latitude of the image will almost immediately help to explain the strange features that you see in each picture.

The hi-res photo to the right, rotated, cropped, and reduced to post here, was taken on May 22, 2022 and provides us a great example. The jumbled features in the depression on the image’s right half surely look like the glacial features seen routinely in the 2,000-mile-long strip found in the 30 to 60 degree band in the chaos terrain of the northern lowland plains. In fact, it is likely that cycles of ebb and flow of those glaciers helped shape this chaos of buttes and mesas and cross-cutting canyons.

This picture however is nowhere near any chaos terrain, or that 2,000 long strip. In fact, it is instead in an area that appears mostly formed by tectonic and volcanic activity, as the overview map below shows.
» Read more

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Perseverance: Evidence of both past lava and liquid water on the floor of Jezero Crater

1:40 pm

Figure 6: Two models for geological history of Jezero Crater

Two new papers (here and here), published last week in Science and using data obtained during Perseverance’s first year of roving on Mars, strongly suggest that the floor of Jezero Crater was first formed by lava flows, either from impact or later flows from eruptions, followed by a period where liquid water interacted with these igneous materials to produce the chemistry seen today. From the first paper:

After emplacement of the igneous rocks on the crater floor, multiple forms of aqueous interaction modified—but did not destroy—their igneous mineralogy, composition, and texture. Evidence for alteration includes the presence of carbonate in the Séítah abrasion patches, the iron oxides in the Máaz formation abrasion patches (which we presume are due to iron mobilization and precipitation), and the deposition of salts including sulfates and perchlorate. More broadly, the appearance of possible spheroidal weathering textures suggests that aqueous alteration played a role in rock disintegration.

The graphic to the right, figure 6 in the first paper, shows two different models for the geological formation of the floor of Jezero Crater. “Basalt emplacement” are the lava flows.

According to the press release today [pdf], the first core samples that the rover gathered for later pickup and return to Earth will likely show the following:

The salts include sulfates, similar to Epsom salts, which are common on Mars. Most importantly, high levels of chlorine-containing salts are also present, such as chlorides (“table salt”) and perchlorates. These highly soluble salts reveal that the rocks were soaked in brines, and hence contain clear evidence of liquid water.

The on-going big geological mystery of Mars remains. The data suggests liquid water once existed as some form in Jezero Crater. Other data suggests liquid water existed elsewhere on Mars as well. Yet, no model exists that anyone accepts with any confidence that makes it possible for liquid water to exist on the Martian surface. Its atmosphere has always been either too cold or thin.

To underline this conundrum, note that in the graphic above, neither model includes a time period when liquid water sat on top of these layers. Though the evidence calls for liquid water at some time, the scientists do not feel confident enough to include it in these initial models.

One possible explanation that I sense some scientists are beginning to consider is the chemical interaction of melted ice at the base of past long gone ice glaciers. The ice would be frozen, but the glacier’s movement might create pockets of liquid water at its base, which over eons might result in these chemical reactions. If Jezero Crater had once been filled with glaciers, as many Martian craters in the mid-latitudes appear to be now, this could have provided the water necessary for the chemical modifications the scientists are finding.

This theory however is entirely speculative on my part, and has not yet been proposed by any scientists, though I have seen hints of it in a number of different research papers.

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InSight power levels continue to hold steady

2:35 pm

InSight power levels through August 27, 2022

According to a new update posted today by the InSight science team, the power being generated by the lander’s dust-covered solar panels once again did not decline last week, holding at 400 watt-hours generated per day for the fifth week in a row.

The graph to the right shows the trends since May. The dust in the atmosphere is indicated by the red line, marking what scientists call the tau level. A normal level outside of the winter dust season should be between 0.6 and 0.7 tau. Even though that dust season has been ending, that level has remained high, thus cutting off more of the sunlight that the Mars lander could use to generate the electricity needed by its seismometer.

That the power generated continues to hold steady however suggests that InSight’s seismometer might be able to continue working into September, detecting Martian earthquakes. The scientists had predicted the spacecraft would die sometime around now. Without doubt they are thrilled their prediction appears wrong.

That the lander might last longer also increases the chance that it might experience a wind event, such as a dust devil, that could blow the solar panels clear of dust and save the lander entirely. All it needs is one such event, which sadly has not occurred since InSight landed on Mars in 2018.

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Martian auroras as seen by UAE’s Al-Amal orbiter

10:42 am

Aurora types on Mars
Click for full image.

Using data gathered by the Al-Amal orbiter (“Hope” in English), scientists have identified three types of aurora on Mars. The image to the right, figure 1 from their paper, shows these types, crustal field aurora, patchy aurora, and sinuous aurora. From the abstract:

We categorize discrete auroral patterns into three types: those near strong vertical crustal magnetic field, patchy aurora near very weak crustal fields, and a new type we call “sinuous,” an elongated serpentine structure that stretches thousands of kilometers into the nightside from near midnight in the northern hemisphere.

All three types generally occur during the Martian night, and evolve quickly over periods of less than 45 minutes. The first type, which is generally the brightest, forms over terrain where Mars’ residual magnetic field is strongest and vertically oriented, and was most often seen over the southern cratered highlands centered between the large impact basins Argyre and Hellas. The third type, sinuous aurora, was more unusual:

These we are calling “sinuous discrete aurora,” due to their thin, elongated, and sometimes serpentine shapes. They share several key traits: (a) they appear in the northern hemisphere away from strong crustal fields, (b) they usually connect to the dayside in the far north but also sometimes separately at lower latitudes, (c) they extend for thousands of kilometers into the night side, (d) they appear on both dusk and dawn sides, and (e) their shapes change moderately and brightnesses shift by factors of up to two over timescales of ∼20 min (i.e., the time between swaths, as shown in the differences between Figures 1j and 1k [in the figure above).

The existence of aurora on Mars has been known since the 2000s. These observations however are the first that show more details beyond a fuzzy patch.

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Changes on Mercury detected by Messenger over four year time period

9:43 am

Changes on Mercury seen by Messenger from 2011 to 2015

Using archival data collected from 2011 to 2015 while the orbiter Messenger circled Mercury, scientists have located twenty spots on the planet where something changed during that time period. The map to the right, adapted from the paper, indicates those locations. From the paper’s abstract:

We identified at least one change likely resulting from a newly formed impact crater with bright rays that extend away from the site. If all the changes result from impact events, then the present-day rate of impactors striking the innermost planet is 1,000 times higher than models predict. Therefore, we investigate other sources for these detected changes. We located several changes on steep slopes near tectonic landforms, consistent with ongoing tectonic activity. Additionally, we identified several changes in areas adjacent to hollow formations, consistent with present-day activity. These detected changes will be critical targets for the upcoming BepiColombo mission.

The data suggests several things. First, if the changes all come from impacts, than the number of asteroids in the inner part of the solar system where Mercury orbits the Sun is much higher than believed. Since it is very hard to observe asteroids there because of the Sun, this very well might be true.

Second, if the changes were not all caused by impacts, then they occurred either from earthquakes or the environmental extremes caused by daily and seasonal changes.

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Curiosity in the valley of Gediz Vallis

11:41 am

Curiosity's view on sol 3576 (August 28, 2022)
Click for full image.

Overview map
Click for interactive map.

The panorama above was created by Curiosity’s right navigation camera on August 28, 2022, and shows the strangely paved Martian terrain directly in front of the rover now that it is inside the valley of Gediz Vallis, scattered flat rocks interspersed with dust. The yellow lines in the overview map to the right indicates the area covered by this panorama. The red dotted line indicates the rover’s likely future route to circle around the small mesa Chenapua.

The paved rocks however may not be separate, but merely covered in their low spots by dust. What makes these light rocks significant is that they appear to be the first close examples of the sulfate-bearing layer that the rover has seen in the higher reaches of Mount Sharp since it landed in Gale Crater more than ten years ago. You can see this bright layer clearly in the distance in a panorama taken by Curiosity in June 2021. The rover has now finally reached it, and is about to delve into another layer in the geological history of Mars, a layer that appears easily weathered and carved by the thin Martian atmosphere.

Other details in this panorama are of important note. In the overview map, I have indicated that a recurring slope lineae is supposed to exist on the cliff face of the mesa dubbed Orinoco. These lineae, seen from orbit, appear to be streaks on slopes that come and go seasonally. No one has come up with a theory to explain them, though the most favored theory today says they are staining dust flows of some kind.

However, if you click on the panorama and zoom in on the cliff face of Orinoco, you will see an incredibly rough rocky terrain. It seems impossible for any streak of any kind to flow down this cliff anywhere, suggesting that the streaks might possibly be like the rays that radiate out from craters on the Moon, visible only from orbit and invisible on the surface.

The marker layer is another important geological target, now almost within reach. This flat layer is found in many places on the flanks of Mount Sharp, all at about the same approximate elevation. It is distinctly flat and relatively smooth. Knowing why it stands out so differently from the layers above and below will help geologists better write the geological history of this Martian mountain and the crater in which it sits.

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Swirls and mesas in Valles Marineris

1:39 pm

Swirls and mesas in Valles Marineris
Click for full image. For the original of the inset go here.

Cool image time! The picture to the right, rotated and cropped to post here, was taken on June 13, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as “fractures in West Candor Chasma,” one of the side canyons that form Mars’ gigantic Valles Marineris, the largest canyon system known in the solar system.

To my eye, I don’t see fractures as much as swirling and curving outcrop ridges, as if the twisted layering here is so steeply tilted so that it is almost vertical, with the more resistant edges sticking up out of the dust and dunes. The color corrected inset zooms in on some of these swirls, though this better view hardly clarifies things. Note how the upper curves seem to suddenly cut off, almost as if someone had sliced them with a knife. Don’t ask me to explain.

The overview map shows us where this spot is within Valles Marineris.
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Eroding glacial ice on Mars, dipping in the wrong direction

1:00 pm

Dipping wrongway ice terraces
Click for full image.

Today’s cool image is a variation of a similar phenomenon shown in a cool image I posted in July, dipping terraced layers stepping downhill toward a cliff face, rather than away from the cliff as you would expect. That previous example was located in chaos region in the northern mid-latitudes that I dub glacier country.

This example is instead found a completely different region of Mars, halfway across the planet. The photo to the right, cropped, reduced, and annotated to post here, was taken on March 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The arrows indicate the downward trend of those dipping layers, toward the cliff face.

The overview map below provides the context.
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A pit in the dry-ice polar cap of Mars

3:48 pm

A pit in the dry-ice cap of Mars
Click for full image.

This cool image is possibly of some of the most alien terrain on Mars. The photo to the right, rotated and cropped to post here, shows a pit (not a peak) in the dry-ice cap that covers a small portion of the southern polar ice cap on Mars. North is up. It was taken on June 16, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). In fact, at 88 degrees south latitude, the image is just about as far south as it is possible for MRO to take pictures. Beyond this the orbit does not reach.

If you look close, you can see that there are several distinct layers in the sunlight eastern interior slopes of the pit. The base of the pit itself appears to have ripples, as if their might be Martian dust trapped inside.

This is a very cold and alien place. The ground is made of dry ice. The temperatures are always cold, well below minus 100 degrees Fahrenheit.

If you look at the full image, you will see that, except for the very tiny pit nearby to the east, this pit is all by itself. If the underlying terrain caused this sinkhole to form, why only here?

The overview map below shows the location, which might help explain things.
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