Tag: geology

Cracking scallops in the Mars

12:32 pm

Cracking scallops on Mars
Click for original image.

Cool image time! The picture to the right, cropped to post here, was taken on September 27, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this “scallop-hosting mantle”. In other words, the surface here has a mantle of material that is for a variety of reason cracking and producing these north-facing scallops. That mantle also appears layered, since it descends downward in terraced steps as you travel north. This particular terrace drops about 40 feet.

Scientists believe [pdf] these scallops are formed in connection with the sublimation of underground ice.

According to [one hypothesis] scallop formation should be ongoing at the present time. Sublimation of interstitial ice could induce a collapse of material, initially as a small pit, then growing southward because of greater solar heating on the southern side. Nearby scallops would coalesce together as can be seen to have occurred.

In the case of the image to the right, this sublimation is also accompanied by a drying process similar to cracks one sees in dried mud. As the ice sublimates away the remain material shrinks and cracks.
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Perseverance moves on

10:30 am

Perseverance panorama, November 16, 2025
Click for high resolution version. For original images, go here, here, and here.

Overview map
Click for interactive map.

Cool image time! It appears that during the government shutdown the science team for the Perseverance rover on Mars made the decision to leave an area they had been exploring for the past two months, driving the rover aggressively to the southwest and in a direction that had been unplanned.

The overview map to the right illustrates that move, with the blue dot marking the rover’s present position. The white dotted line indicates its actual travels, while the red dotted line shows the planned route. According to that planned route, the plan had been to move south and back up onto the top of the rim of Jezero Crater. For reasons that the science team has not explained, they decided instead to head to the southwest, away from the crater rim.

The panorama above was created by stitching together three images released today by Perseverance’s left navigation camera (see here, here, and here). The yellow lines on the overview map indicate my guess as to the area covered by this panorama. Note Perseverance’s tracks on the left. I think this panorama shows us the area the rover traveled in this recent move.

Note also the barrenness of the terrain. This is truly an alien world. It has an atmosphere that produces a very faint wind, that over eons can erode things. This is why this exterior wall of the rim of Jezero crater is so relatively smooth. Crater rims are usually places of jagged broken rock, thrown out by the impact. That very thin Martian atmosphere over time has smoothed that terrain.

This landscape also has no life. Except for some spots in the polar regions, it is literally impossible to find any place on Earth so devoid of life.

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The edge of Mars’ north polar ice cap

11:47 am

The fringe of Mars' perennial ice cap
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 29, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The picture shows what the science team labels as a “fringe of perennial ice.” For this picture, north is down. The white stuff on the top half of the image is that perennial ice, while the dark material at the bottom is likely a mixture of dust and debris that is still impregnated with ice.

Mars is a very icy world. Orbital data now suggests that above 30 degrees latitude there is a lot of near surface ice, though it is often mixed in with the red planet’s ample dust, blown there for eons. This location however shows us a place where that ice is on the surface, and is generally pure.

That does not mean however this will be a good location to establish a colony.
» Read more

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Curiosity looks downhill at past travels

9:31 am

Curiosity looks downhill
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on November 6, 2025 by the left navigation camera on the Mars rover Curiosity.

The picture looks north across Gale Crater, its distant rim about 20-30 miles away barely visible in the dusty atmosphere. In the foreground can be seen Curiosity’s recent tracks, showing how the science team had it travel back and forth several times, probably to check out several different interesting nearby ground features, as well as see how the ground changed by that travel. The rover has been traveling in an area called boxwork, a series of small intercutting ridges and hollows. Several of those ridges can be seen just beyond the tracks.

The red dotted line indicates my rough estimate as to the rover’s route uphill to get to this point, traveling up and to the left and following ridges just out of view.
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Crazy layers inside a Martian crater

2:49 pm

Crazy layers in a Martian Crater
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 30, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists label this image with the term “layers”, but to my eye this is kind of an understatement. The geology in the top half of this picture is more than simply layers, it is an example of that unique Martian geological feature dubbed “brain terrain”, but on steroids.

No one yet knows what causes brain terrain, though scientists think it is related to the sublimation of near surface ice. Normally the tubelike formations are much smaller, only ten to thirty feet long, not hundreds of feet as we see here.

In this case the location of these features makes their formation even more puzzling, as there is no near surface ice found here.
» Read more

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Webb tracks volcanic eruptions on Io

9:59 am

Different Webb infrared detections of Io over time
Click for original image.

Using the Webb Space Telescope, scientists have tracked two different volcanic eruptions on Io that too place from 2022 to 2023, detecting sulfur monoxide both from those eruptions as well as sulfur from the magnetic plasma torus produced as the planet travels through Jupiter’s strong magnetic field. From the paper’s abstract:

Volcanic thermal emission was detected from Loki Patera and Kanehekili Fluctus [two volcanic vents]. The main changes in the shape of the thermal emission spectra since [Webb] observed Io in November 2022 were consistent with the continued cooling of emplaced lava flows in the Kanehekili Fluctus region, and the crust that had formed on the surface of the lava lake in Loki Patera. Images of Io in the SO 1.707 ฮผm emission band [sulfur monoxide] show a concentration above Kanehekili Fluctus and in two regions in the northern hemisphere. The emissions are sourced from SO molecules ejected from volcanic vents. We further detected, for the first time, sulfur line emissions at 1.08 and 1.13 ฮผm. These emissions are distributed homogeneously across a band in Io’s northern hemisphere. They are mainly produced through excitation by electrons from the plasma torus, penetrating Io’s atmosphere.

The top image to the right shows the heat signature above the two volcanoes, one to the southwest and the second to the northeast. The middle image shows the sulfur monoxide emissions detected by Webb above those volcanoes from their on-going eruptions. The bottom image shows the more diffuse sulfur emissions, mostly in the northern hemisphere, believed produce by interactions with the plasma torus.

This research also relied on data obtained by both the Keck telescopes in Hawaii and the Hubble Space Telescope.

There are of course uncertainties with these results. For example, the conclusion that the more diffuse sulfur is produced by interactions with the plasma torus is not as certain. First, those sulfur emissions still appear closely linked to the volcanoes, which suggests this still could be a source.

Second, the observations also cover only two data points in time, in 2022 and 2023. To get a more precise map of the activity on Io we really need an orbiter there observing the planet on a continuous basis, something that is at this time impossible, not only because no mission is planned but because the hostile radiation environment this close to Jupiter makes the engineering quite challenging. It is this reason why Europa Clipper is not going into orbit around Europa when it arrives there in 2031. Better to orbit Jupiter and only periodically dip into that harsh radiation environment.

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This typical cliff on Mars just happens to match the walls of the Grand Canyon

1:27 pm

A typical Martian cliff, comparable to the Grand Canyon
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 23, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The label the science team gave this image, “remnant fan”, suggests the focus of research here is the fingerlike ridges on the floor of the canyon, emanating out from the cliff. These appear to be the remains of an ancient mass-wasting event, similar to an avalanche but different in that instead of it being a pile of surface material falling down the cliff, the cliff itself breaks free and slumps downward. In this case the event was so long ago that most of the slumped material has eroded away, leaving only those ridges, likely resistant to erosion because of the impact of the material from above.

If you look at the top of cliff, you can see evidence that another mass wasting event is pending. Note how the plateau floor near the cliff has dropped about 100 feet. This drop suggests that this part of the cliff has started to slump and break away from the plateau.
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The alien landscape of Mars’ north polar ice cap

1:29 pm

The strange terrain of Mars' north polar ice cap
Click for original image.

Cool image time! The picture to the right, cropped to post here, was taken on August 24, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team labels this simply as a “terrain sample,” which usually means it was not taken as part of any specific research request, but to fill a gap in the camera’s schedule in order to maintain its proper temperature. When they need to do this, they try to find interesting things to photograph, and mostly succeed.

At first glance the picture to the right does not appear that interesting. If anything it shows an endless expanse of mottled terrain, with no features of any interest at all. This sameness however is what makes this picture and landscape intriguing. What caused it to look this way?
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Weird “What the heck?!” pedestal crater on Mars

1:10 pm

A
Click for full image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken on August 26, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). While the full image shows what the camera team labels as the “ridges” that cover this area, the most prominent feature in the whole landscape is this half-mile-wide pedestal crater, sitting about 50 to 100 feet above the surrounding terrain.

What makes this strange butte so weird is the plateau on top, criss-crossed with ridges and hollows in a manner that defies any obvious geological explanation.

Pedestal craters are not uncommon on Mars, and in fact a bunch of others are found throughout this region. The theory for their formation is that they formed when the surface here was much higher. The impact made the crater floor more dense and resistant to erosion, so as the surrounding terrain wore aware the crater ended up being a butte.

However, pedestal craters usually have relatively smooth tops, making this crater another example of a “What the heck?” image.
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A somewhat typical volcanic vent on Mars

12:46 pm

Overview map

With today’s cool image we begin with the overview map to the right. The white dot marks the location, within the region on Mars dubbed the Tharsis Bulge, where four of its biggest volcanoes are located on a surface that has been pushed significantly above the red planet’s mean “sea level.”

The small rectangle in the inset shows the area covered by the cool image below. The focus is on a two-mile-long and half-mile-wide depression that sits on a relatively flat landscape of few craters.

If you look at the inset closely, you will notice this depression is surrounded by a dark borderline on all four sides, ranging in distance from three to thirteen miles. The grade to that borderline is downhill in all directions, with the drop ranging roughly from 800 to 1,000 feet.

So what are we looking at? » Read more

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Small fresh impact on Mars’ youngest major lava flow

1:25 pm

Monitoring a fresh impact on Martian lava
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 26, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team labels this “Monitoring New Impact Site.” The fresh impact, indicated by the three dark patches just left and up from center, is actually not that fresh. It was first photographed by MRO on September 27, 2008. This newer picture is to see if anything significant had changed in the subsequent seventeen years.

In comparing the two pictures, the only change that is obvious is that the patches have faded and become less distinct. Nothing else appears different.

The surrounding terrain however is interesting in its own right. The landscape is remarkably flat, though it has that meandering ridge coming out from that lighter patch in the lower right. What are we looking at?
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Meandering channel in Mars’ southern cratered highlands

1:25 pm

Meandering channel on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 30, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Dubbed a “channel” by the MRO science team, it shows us a meandering canyon with a floor that seems filled with corroded linear features seen frequently on Earth glaciers. Here, the linear ridges appear broken, in many places missing, and in other places so broken their linear nature disappears.

If this was on Earth and I was a global warming activitist, I would immediately claim that the glacier has been evaporating away due to a warming climate caused by SUVs and Republican intransigence. This however is on Mars, where there are no SUVs or Republicans. So what is going on?
» Read more

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