Tag: geology

American camera snaps picture of shadowed floor of Shackleton crater

10:03 am

floor of Shackleton Crater
Click for original image.

Using ShadowCam, a NASA-funded camera designed to take high resolution images of the permanently shadowed regions on the Moon, scientists have snapped the first picture of shadowed floor of Shackleton crater.

That image, reduced to post here, is to the right. I have added some labels to clarify what we are seeing. The arrow points to a boulder track caused when the boulder rolled down the crater rim slope.

The camera will be used to image the moon’s permanently shadowed regions with a resolution of better than 6.6 feet (2 meters) per pixel

ShadowCam is one of six instruments on the South Korean lunar orbiter, Danuri, which is now in lunar orbit and beginning its science phase. This was therefore only a successful test image to make sure the camera was working as planned.

Though the area photographed was in shadow (otherwise it would have saturated ShadowCam’s sensitive camera), this first image appears to show no ice at the base of the crater. This simply could be that this part of the crater floor is not permanently shadowed, but gets illuminated enough to melt off any ice. Or it could be that no ice exists in these places. We need to wait and see.

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A collapse on Mars

1:34 pm

A collapse on Mars
Click for full image.

The photo to the right, cropped, reduced, and enhanced to post here, was taken on October 27, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The full photo was simply labeled as a “collapse feature”, and because it contained a few other sinks to the north beyond the top edge of this cropped picture, it is unclear if the scientists were referring to this sink in particular.

This sink is the most interesting however, because it really looks like something had sucked material out from below, causing the surface crust to fall downward, intact except for some cracks along the perimeter of the collapse.

The overview map below as always provides some context that might explain what we are seeing.
» Read more

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A new hotspot map of Io, based on Juno data

11:52 am

Hot spot map of Io
Click for original figure.

Scientists have compiled a new map of the many volcanic hotspots on the Jupiter moon Io, based on data obtained by Juno, including 23 spots previously undetected. From the paper’s abstract:

We mapped the hot spot distribution on Io’s surface by analyzing the images acquired by the JIRAM instrument onboard the Juno spacecraft. We identified 242 hot spots, including 23 not present in other catalogs. A large number of the new hot spots identified are in the polar regions, specifically in the northern hemisphere. The comparison between our work and the most recent and updated catalog reveals that JIRAM detected 82% of the most powerful hot spots previously identified and half of the intermediate-power hot spots, thus showing that these are still active. JIRAM detected 16 out of the 34 faint hot spots previously reported.

The map above is taken from figure 2 of the paper. The data, when compared to other earlier data, confirms that many of these hot spots are long-lived, and have been erupting now for decades.

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Ingenuity about to fly up onto the delta

10:21 am

Overview map
Click for interactive map.

The engineering team that operates the helicopter Ingenuity on Mars announced today that the next flight, #39, will go about 456 feet and travel to the northeast.

The green dot on the map to the right shows Ingenuity’s present location. The yellow lines indicate the territory within which this flight will head. If successful it will be the first time the helicopter has left the floor of Jezero Crater, and moved uphill onto the delta that flowed into that crater sometime in the far past.

The blue dot marks Perseverance’s present location. The dotted red line indicates its eventual planned route on that delta.

The engineers state that their flight goal is to “flight test new software”. This new software is supposed to allow Ingenuity to fly over rougher terrain. On the 38th flight, it proved its worth by not only flying over an area of rippled sand dunes, it landed between two.

This next flight, scheduled for sometime today, will be even more challenging, because the helicopter will have to fly upward above higher terrain.

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Defrosting Martian Dunes

3:07 pm

Defrosting Martian dunes
Click for full image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was a captioned image on January 6, 2023 from the science team of the high resolution camera on Mars Reconnaissance Orbiter (MRO). From the caption by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

In the late winter when first illuminated, the carbon dioxide frost at high latitudes will begin to sublimate. Over sand dunes, the defrosting spots and mass wasting on steep slopes produce striking patterns. This scene is especially artistic given the shapes of the dunes as well as the defrosting patterns.

» Read more

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The dry and dusty equatorial regions of Mars

1:50 pm

The dry cratered highlands of Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on October 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a cluster of craters filled with ripple dunes.

The color strip tells us something [pdf] about the surface materials here. The reddish-orange in the craters is thought to be dust. The greenish terrain above the craters is likely coarse rock or bedrock, covered with a veneer of dust.

There is no ice here, just dust that over time has become trapped in the craters and cannot escape. And though there is also dust on the surrounding terrain, there is not that much. The craters themselves are likely very ancient, based on their shape and the eroded condition of their rims.

» Read more

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Drainage out of a Martian crater

12:42 pm

Drainage out of a Martian crater
Click for full image.

Today’s cool image to the right, rotated, cropped, reduced, and sharpened to post here, not only gives us another example of a Martian geological feature that is unique to Mars and whose origins are not yet understood, it also shows what appears to have once been a lake-filled crater that over time drained out to the east through a gap.

This picture was taken on October 14, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The inexplicable geology is called brain terrain, and it fills the floor of the crater on the picture’s left side. The rim shows a gap, from which a meandering channel continues downhill to the east. The lake inside the crater might not have been liquid water, but ice. The channel might not have been formed by flowing water, but by a glacial flow downhill.

What makes this glacial evidence especially interesting is that it is located in a very different part of the Martian mid-latitudes.
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China releases first update on status of Yutu-2 since September

12:46 pm

Yutu-2's travel path through December 2022
Click for full image. The red flag marks the landing site.

China today released its first update since September on the status of its Yutu-2 rover on the far side of the Moon. The map on the right shows the rover’s travels through December 2022.

As of today the rover has traveled 4,774 feet total, and about 450 feet since September. The goal, as stated in April 2021, was to “move northwest toward the basalt distribution area located about 1.2 km away.” At the time the rover was only averaging about 100 feet travel per lunar day. According to these numbers, it picked up the pace in the past year, though it is unclear whether it has reached that goal.

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The soft icy Martian northern lowland plains

11:15 am

The soft icy Martian northern lowland plains
Click for full image.

In a cool image post last week, I noted that the near surface “ice sheets in the northern lowland plains are never … smooth, even if well protected.” The picture to the right, cropped, reduced, and sharpened to post here, provides an excellent example. It was taken on November 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It is winter, and the sunlight is coming from the southwest, only 27 degrees above the horizon. The mound on the left is soft, while the depression on the upper right appears to have sand dune ripples sitting on top of a flat glacial mound. This depression may be an eroded crater (no upraised rim) or it could be a sink caused by the sublimation of the near surface ice.

Everywhere else the flat plains are stippled with small knobs.

The overview map below provides more context.
» Read more

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Largest volcanic eruption in years detected on Io

9:49 am

Using instruments on a ground-based telescope, one scientist based at the Planetary Science Institute (PSI) in Arizona has detected the largest volcanic eruption in years on the Jupiter moon Io.

PSI Senior Scientist [Jeff] Morgenthaler has been using IoIO, located near Benson, Arizona to monitor volcanic activity on Io, since 2017. The observations show some sort of outburst nearly every year, but the largest yet was seen in the fall of 2022. Io is the innermost of Jupiter’s four large moons and is the most volcanic body in the Solar System thanks to the tidal stresses it feels from Jupiter and two of its other large satellites, Europa and Ganymede.

IoIO uses a coronagraphic technique which dims the light coming from Jupiter to enable imaging of faint gases near the very bright planet. A brightening of two of these gases, sodium and ionized sulfur, began between July and September 2022 and lasted until December 2022. The ionized sulfur, which forms a donut-like structure that encircles Jupiter and is called the Io plasma torus, was curiously not nearly as bright in this outburst as previously seen. “This could be telling us something about the composition of the volcanic activity that produced the outburst or it could be telling us that the torus is more efficient at ridding itself of material when more material is thrown into it,” Morgenthaler said.

The material released by this eruption could impact Juno during future close approaches of Jupiter.

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A spray of Martian hollows

11:42 am

A spray of Martian sinks
Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 12. 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Dubbed simply as a a “terrain sample” by the science team, the picture was not taken as part of any specific research project, but instead to fill a gap in the orbiter’s shooting schedule so as to maintain the camera’s proper temperature. When MRO’s science team does this, they try to pick something in the area below that might be interesting. Sometimes they succeed, but often the features in the picture are nondescript.

The white line delineates the rim of a faint and very eroded small crater. Are the depressions that are mostly concentrated just to its south and east sinks or past impact craters? I haven’t the faintest idea. The overview map below helps to answer this question, but only partly.
» Read more

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A hint at Mars’ past climate cycles

11:16 am

Terraced glaciers in Martian crater
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on October 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a “layered feature” inside a small 4,500-foot-wide crater.

Located at 36 degrees north latitude, we are likely looking at glacial ice layers inside this crater, with each layer probably marking a different Martian climate cycle. The terraces suggest that during each growth cycle the glaciers grew less, meaning that less snow fell with each subsequent cycle. This in turn suggests a total loss of global water over time on Mars.

The overview map below gives us the wider context.
» Read more

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A “What the heck?” glacier image on Mars

5:36 pm

Glacial material on Mars
Click for full image.

Sometimes a cool image goes from bafflement to obvious as you zoom into it. The cool image to the right, cropped to post here, does the opposite. It was taken on October 11, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have purposely cropped it at full resolution, so that its eroded glacier nature is most obvious.

The cracks and hollows are likely caused by the sublimation of the near surface underground ice, breaking upward so that the protective surface layer of debris and dust collapses at some points, and cracks at others.

The overview map below further confirms the likelihood that we are looking at glacial features, but when we also zoom out from this close-up we discover things are not so easily explained.
» Read more

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Using reflected light from Jupiter to photograph Ganymede’s night side

12:15 pm

Ganymede as seen in the reflected light of Jupiter
Click for full image.

During Juno’s June 7, 2021 close fly-by of Ganymede, scientists used its instruments to obtain the first good image of a part of this Jupiter moon. What made the achievement especially amazing was that the area photographed was only lit by the reflected light from Jupiter, the equivalent of its “earthshine.” From the paper’s abstract:

On 7 June 2021, the Juno spacecraft flew within about 1,000 km of the surface of Jupiter’s largest moon, Ganymede. The Mission used their sensitive navigation camera to photograph the moon’s dark side where it was lit only by scattered sunlight from Jupiter. This new imaging approach revealed multiple surface features, including a patchwork of different surface textures (such as grooved terrain), several craters, and ejecta deposits. These features had not been visible in images collected by previous spacecraft.

The picture to the right is from figure 2 of the paper, cropped and reduced to post here. It shows a region on Ganymede that in the earlier images had shown few details because the lighting was poor and thus features were not easily discerned (as can be seen by the inset in the lower right). In the new picture, the only light was reflected from Jupiter, and its low angle brings out the surface topography.

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Finding Martian glaciers from orbit

11:45 am

Glacier flow on Mars
Click for full image.

Today’s cool image is a great example of the surprises one can find by exploring the archive of the high resolution pictures that Mars Reconnaissance Orbiter (MRO) has produced since it arrived in Mars orbit back in 2006. The picture to the right, rotated, cropped, and reduced to post here, was taken by MRO’s high resolution camera back on May 4, 2017. I only found it because I had picked out a October 24, 2022 high resolution image that covered a different area of this same flow feature just to the north east. In trying to understand that 2022 picture I dug to see other images had been taken around it, and found the earlier 2017 photo that was even more interesting.

Neither however really covered the entire feature, making it difficult to understand its full nature. I therefore searched the archive of MRO’s context camera, which has imaged the entire planet with less resolution but covering a much wider area per picture. The context camera picture below captures the full nature of this feature.
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Cones, mounds, and layers of Martian ice?

2:20 pm

Cones, mounds, and layers of Martian ice?
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on September 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The location is at 38 degrees north latitude, in the Martian northern lowland plains. At this latitude in these plains the geological features seen in high resolution pictures almost always invoke near surface ice, including processes that disturb that underground ice layer.

This picture is no different. Not only does it appear that a glacier is flowing down from the top of east-west ridge, the middle mound includes a crater with its southeast rim gone and appears filled with material that suggests ice.

The greater geographic context of this location can be seen in the overview map below.
» Read more

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Crater at the edge of the Martian south pole ice cap

11:20 am

Oblique view of south pole crater
Click for full image.

Overview map

Cool image time! The oblique panorama above, reduced and sharpened to post here, was created from an image taken on May 19, 2022 by the European orbiter Mars Express. Its location on edge of the layered deposits of ice and dust that form most of the Martian southern ice cap is indicated by the white rectangle on the overview map to the right. From the press release:

While it may look like a winter wonderland, it was southern hemisphere spring at the time and ice was starting to retreat. Dark dunes are peeking through the frost and elevated terrain appears ice-free.

Two large impact craters draw the eye, their interiors striped with alternating layers of water-ice and fine sediments. These ‘polar layered deposits’ are also exposed in exquisite detail in the rusty red ridge that connects the two craters.

The scattered white patches are either water frost, or the winter mantle of dry ice, both now sublimating away with the coming of spring.

The black line on the overview map indicates the extent of the layered deposits, and suggest that the ridgeline is not considered part of that ice cap layer, in contradiction to the press release language above.

Which is it? I would guess the answer is simply the uncertainty of science. Some scientists took a look here and decided the ridge was actually a base layer sticking up through the layered deposits. The European scientists who took this picture have instead concluded, based on the image, that the ridge is part of the layer deposits.

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Bursting lava bubbles on Mars

10:58 am

Burst lava bubbles on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 4, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

I really have no idea what caused these distorted cones. My intuition (a dangerous thing to rely on when it comes to science) suggests these are volcanic in nature. Imagine hot lava with gas bubbling up from below. Periodically a gas bubble will burst on the surface releasing the gas. Depending on temperature, that bursting bubble could harden in place.

The overview map below provides some support for my intuition, but it also suggests this first hypothesis could be completely wrong, something that does not surprise me in the least.
» Read more

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Perseverance deposits first core sample for pickup later

8:57 am

Perseverance's location December 21, 2022
Click for interactive map.

The Mars Perseverance rover has now deposited its first core sample on the floor of Jezero Crater for pickup later by a future Mars helicopter for eventual return to Earth.

A titanium tube containing a rock sample is resting on the Red Planet’s surface after being placed there on Dec. 21 by NASA’s Perseverance Mars rover. Over the next two months, the rover will deposit a total of 10 tubes at the location, called “Three Forks,” building humanity’s first sample depot on another planet. The depot marks a historic early step in the Mars Sample Return campaign.

The blue dot on the map to the right shows this location. The green dot shows Ingenuity’s present position. The red dotted line the rover’s future travel route.

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InSight mission ended

3:01 pm

Location of InSight's largest quakes
The white patches mark the locations on Mars of the largest quakes
detected by InSight

NASA today announced that it has officially ended the mission of the InSight lander on Mars.

Mission controllers at the agency’s Jet Propulsion Laboratory (JPL) in Southern California were unable to contact the lander after two consecutive attempts, leading them to conclude the spacecraft’s solar-powered batteries have run out of energy – a state engineers refer to as “dead bus.”

NASA had previously decided to declare the mission over if the lander missed two communication attempts. The agency will continue to listen for a signal from the lander, just in case, but hearing from it at this point is considered unlikely. The last time InSight communicated with Earth was Dec. 15.

Other than the success of InSight’s seismometer, this project was mostly a failure. Its launch was delayed two years, from 2016 to 2018, because of problems with the original French seismometer, forcing JPL to take over. Then its German-made mole digger failed to drill into the Martian surface, causing the failure of the lander’s second instrument, a heat sensor designed to measure the interior temperature of Mars.

Fortunately the seismometer worked, or otherwise it would have been a total loss. That data has told us much about Mars and its interior.

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The same region on Ganymede, as seen by Voyager-1 in 1979 and Juno in 2021

11:30 am

Ganymede compared between Voyager-1 and Juno
Click for full image.

When the Jupiter orbiter Juno did a close pass of the moon Ganymede on June 7, 2021, it took four pictures, covering regions mostly photographed for the first time by Voyager-1 in its close fly-by in 1979.

Scientists have now published the data from this new fly-by. Though Juno’s higher resolution pictures revealed many new details when compared with the Voyager-1 images from four decades earlier, the scientists found no changes. The comparison image, figure 2 of their paper, is to the right, reduced and sharpened to post here.

A flicker comparison between the registered JunoCam and Voyager reprojected mosaics revealed no apparent new impact features. Given the high albedo of fresh craters on Ganymede, with high albedo ejecta deposits two or three times the diameter of the craters themselves, we argue that new craters as small as 250 m diameter would be detectable in images at these 1 km per pixel scales. Extrapolating Ganymede cratering rates from Zahnle et al. (2003) below 1 km, the probability of JunoCam observing a new crater over 12.2 million km2 in 42 years is 1 in 1500, consistent with none being observed.

In other words, at these resolutions finding no new impacts is not a surprise.

Of the new features detected, the Juno images could see more details in the bright rays emanating from the crater Tros (in the lower center of both images), and thus found “…terrain boundaries previously mapped as ‘undivided’ or as ‘approximate’, several large craters, and 12 paterae newly identified in this region.”

Paterae resemble craters but are thought to be a some form of volcanic caldera. Their geological origin however is not yet completely understood.

The paper’s conclusion is actually the most exciting:

The insight gained from this handful of images makes it likely in our opinion that new observations from the upcoming JUICE and Europa Clipper missions will revolutionize our understanding of Ganymede.

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A congregation of Martian dust devils

12:13 pm

A congregation of Martian dust devils
Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 9, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a spot on Mars where, as indicated by the many many tracks, dust devils routinely develop and travel across the surface.

Though this whole region appears to favor dust devils, within it are places that are even more favored. For example, the number of tracks on the northern and eastern slopes of that small hill at center left practically cover the surface, while the hill’s western and southern slopes are almost untouched.

Both the overview map and the global Mars map below provide the full context.
» Read more

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Perseverance’s planned route up onto the Jezero Crater delta

9:55 am

Perseverance's future route onto the delta
Click for original image.

Even as the Perseverance science team prepares to cache the ten first core samples on the surface of Mars for later pickup by a future Mars helicopter for return to Earth, they have also released the planned route they intend to follow as they drive the rover up onto the delta that flowed into Jezero Crater in the distant past.

The black line on the map to the right shows that route, with the black dots indicating points in which further core samples will likely be taken. The red dot indicates Perseverance’s present position, with the white line indicating its past travels. The green dot marks Ingenuity’s present position.

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InSight fails to respond during scheduled communications session

8:36 am

InSight's daily power levels as of December 12, 2022

Since December 15, 2022 engineers have been unable to contact the Mars InSight lander, which likely means its power levels have finally fallen so low that the spacecraft is no longer functioning.

On Dec. 18, 2022, NASA’s InSight did not respond to communications from Earth. The lander’s power has been declining for months, as expected, and it’s assumed InSight may have reached its end of operations. It’s unknown what prompted the change in its energy; the last time the mission contacted the spacecraft was on Dec. 15, 2022.

The graph to the right shows the decline in InSight’s power levels since May. The atmosphere has been clearing following the dust storm in October, indicated by the drop in the tau level. Normal tau levels outside of dust storm season are around 0.6-0.7. It is therefore likely that as this dust cleared, it also settled on InSight’s solar panels, and reduced their ability to generate power to the point the spacecraft ceased functioning.

This is very much the same thing that put the rover Opportunity out of business in 2019.

According to this update, engineers are going to continue to try to contact the lander, but it is likely that this effort will end in about a week, should no contact be successful.

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Big sink near the Martian south pole

12:38 pm

Big sink near the Martian south pole
Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 12, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The image is rotated so that south is at the top. The science team labels this a “subsidence feature,” or in plain English, a sinkhole.

Its perfectly circular shape, plus its central peak, strongly suggests we are looking at an impact crater. However, the lack of a raised rim of debris, produced by the ejecta from the impact, raises questions about this conclusion, and is one reason why the scientists think this is a sinkhole instead. Its shape however could be telling us that this sink is simply mirroring the existence of a buried crater.

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

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The edge of the Martian south pole ice cap

2:42 pm

The edge of the Martian south pole ice cap
Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 4, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The MRO science team labeled this simply “Diverse Terrain,” an apt description but woefully incomplete.

Though the grade here goes uphill to the south, there are ups and downs along the way. The flat areas near the top as well that band near the bottom appear to be the oldest terrain, with the rough hollows appearing to be places where that flat material has sublimated or eroded away.

This terrain is in the very high southern latitudes. South is to the bottom of this picture, with the south pole of Mars about 380 miles away. Thus, that eroding top layer is likely disappearing because it has either water ice or dry ice within it, and over time it sublimates away.

The picture itself was taken in winter, when the entire surface is likely covered with a thin mantle of dry ice that fell as snow with the coming of colder temperatures. A wider view of this region in the spring, taken by MRO’s context camera, shows that this mantle, now appearing like white frost, appears largely confined to the higher terrain. Apparently, the annual sublimation of this dry ice mantle is linked somehow to the erosion of this flat terrain.

The additional location information provided by overview map below helps explain why this terrain is so diverse.
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Ingenuity completes 36th flight; preps for its 37th

10:08 am

Overview map
Click for interactive map.

Ingenuity on December 10, 2022 successfully completed 36th flight, flying about 180 feet to the northwest and then returning the same distance to land at its take-off point.

This was the third flight in a row to land at this point, and was also the third flight since the Mars helicopter’s software was upgraded to allow it to fly higher and over rougher terrain.

The green dot on the map to the right shows Ingenuity’s present position. The blue dot shows where Perseverance presently sits. The rover has been moving eastward, away from the cliff face to the west where it had gathered more core samples, including the first to contain surface regolith (that is, the dirt of Mars).

Engineers are already planning Ingenuity’s 37th flight, which is scheduled for tomorrow and will reposition the helicopter to a new landing spot.

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More results from DART impact of Dimorphos

9:44 am

Didymos and Dimorphos as seen from Earth
Click for movie.

At a science conference this week scientists provided an update on the changes that occurred to the asteroid Dimorphos after it was impacted by the DART spacecraft in September, shortening its orbit around the larger asteroid Didymos by 33 minutes.

The image to the right is a screen capture from a short movie made from 30 images taken by the Magdalena Ridge Observatory in New Mexico, and part of a new image release of the asteroid pair.

It shows the motion of the Didymos system across the sky over the course of roughly 80 minutes, and features a long, linear tail stretching to the right from the asteroid system to the edge of the frame. The animation is roughly 32,000 kilometers across the field of view at the distance of Didymos.

According to the scientists, the impact displaced more than two million pounds of material from Dimorphos.

Observations before and after impact, reveal that Dimorphos and its larger parent asteroid, Didymos, have similar makeup and are composed of the same material – material that has been linked to ordinary chondrites, similar to the most common type of meteorite to impact the Earth. These measurements also took advantage of the ejecta from Dimorphos, which dominated the reflected light from the system in the days after impact. Even now, telescope images of the Didymos system show how solar radiation pressure has stretched the ejecta stream into a comet-like tail tens of thousands of miles in length.

Putting those pieces together, and assuming that Didymos and Dimorphos have the same densities, the team calculates that the momentum transferred when DART hit Dimorphos was roughly 3.6 times greater than if the asteroid had simply absorbed the spacecraft and produced no ejecta at all – indicating the ejecta contributed to moving the asteroid more than the spacecraft did.

This information is teaching us a great deal about these two particular asteroids, which could be used if for some reason their totally safe orbit got changed and they were going to impact Earth. However, NASA’s repeated effort to make believe this info would be useful for deflecting other asteroids is somewhat absurd. It is helpful, but each asteroid is unique. The data from DART is mostly helping astronomers get a better understanding of the geology of these specific asteroids, which will widen their understanding of asteroids in general. Planetary defense is really a very minor aspect of this work.

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Sunken butte on Mars

1:03 pm

Collapsed butte in the Martian northern lowland plains
Click for full image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on November 1, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label a “layered butte.” Like the mesas in the American southwest, those layers, or terraces, mark the geological history of this place, where over time layer upon layer was placed down, and then eroded away except for this mesa.

What makes the mesa even more intriguing and strange, however, are surrounding concentric cracks and the moat at the mesa’s base. These features suggest that at some point the ground below the mesa collapsed so that the entire mesa dropped, as a unit.

What could cause this? The overview map below provides a clue, though certainly not an answer.
» Read more

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Scientists publish papers describing largest Mars quake from May

1:56 pm

Location of May quake

Though news of the largest quake so far detected by InSight on Mars, magnitude 4.7, was released in May, this week the science team published two papers describing the quake itself and what they have learned from it. From the press release:

The waves from the record-breaking quake lasted about 10 hours — quite a while, considering no previous Marsquakes exceeded an hour.

It was also curious because the epicenter was close to but outside the Cerberus Fossae region, which is the most seismically active region on the Red Planet. The epicenter did not appear to be obviously related to known geologic features, although a deep epicenter could be related to hidden features lower in the crust.

Marsquakes are often divided into two different types — those with high-frequency waves characterized by rapid but shorter vibrations, and those of low-frequency, when the surface moves slowly but with larger amplitude. This recent seismic event is rare in that it exhibited characteristics of both high- and low-frequency quakes. Further research might reveal that previously recorded low- and high-frequency quakes are merely two aspects of the same thing, Kawamura said.

The green-dotted white patch on the map above marks the approximate location of this quake, east of where most of the previous larger quakes have been detected and under the Medusa Fossae Formation of volcanic ash. That no surface features appear to correspond to this quake, it is thought it was the result of a shift of underground features.

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