Small fresh impact on Mars’ youngest major lava flow

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

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?
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If there is any microbiology on Mars, new research says it will be found in the red planet’s ample ice

The uncertainty of science: New research that attempted to simulate conditions in the ice on Mars has determined that ancient microbes are more likely survive there for very long periods, as much as fifty million years, rather than the red planet’s dry sediments.

The research team, led by corresponding author Alexander Pavlov, a space scientist at NASA Goddard — who completed a doctorate in geosciences at Penn State in 2001 — suspended and sealed E. coli bacteria in test tubes containing solutions of pure water ice. Other E. coli samples were mixed with water and ingredients found in Mars sediment, like silicate-based rocks and clay.

The researchers froze the samples and transferred them to a gamma radiation chamber at Penn State’s Radiation Science and Engineering Center, which was cooled to minus 60 degrees Fahrenheit, the temperature of icy regions on Mars. Then, the samples were blasted with radiation equivalent to 20 million years of cosmic ray exposure on Mars’ surface, vacuum sealed and transported back to NASA Goddard under cold conditions for amino acid analysis. Researchers modelled an additional 30 years of radiation for a total 50-million-year timespan.

In pure water ice, more than 10% of the amino acids — the molecular building blocks of proteins — from the E. coli sample survived the simulated 50-million-year time span, while the samples containing Mars-like sediment degraded 10 times faster and did not survive. A 2022 study by the same group of researchers at NASA found that amino acids preserved in a 10% water ice and 90% Martian soil mixture were destroyed more rapidly than samples containing only sediment.

In other words, if there was ever microbiology on Mars, it is very unlikely Perseverance or Curiosity will ever find any, roving as they are in the dry Martian tropics.

Though this work has many uncertainties, especially in its assumption that it successfully simulated a 50-million-year time span, the result is hardly an earth-shaking discovery. If anything, it confirms the obvious, which is why NASA’s ludicrous claim that Perseverance’s prime mission is to look for life has always been a lie. It is traveling in the wrong place, a fact that was self-evident from the start.

Whether any microbiology might exist in Mars’ ice however is unknown. The odds are very very low, but not zero. If it does, it is even less likely it is living, based on orbital data.

Layers of Martian ash

Layering 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 31, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this as “layering”, which surely is an apt description. As the latitude is 9 degrees south, this location is within the dry tropics of Mars, where no near surface ice has yet been found. Thus, the terraced layers of this low 20-foot-high mesa are not indicative of the many glacial climate cycles found in the mid-latitudes.

Instead, we are looking at sedimentary layers of rock or dust, laid down over time and later exposed by erosion.

So what caused the layers? And what is causing them to be exposed, one by one? As always the overview map helps provide a possible explanation.
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Peeling brain terrain in Martian crater

Overview map

Peeling brain terrain on Mars
Click for original image.

Today’s cool image takes us once again back to Mars’ glacier country, the 2,000 mile-long mid-latitude strip in the northern hemisphere where almost every image shows glacier features. The picture to the right, cropped, reduced, and sharpened to post here, was taken on September 4, 2025 by the high resolution camera on Mars Reconnaissance Orbiter. It shows a small section of the floor of an unnamed 13-mile-wide crater, highlighting what the science team labels vaguely as “features.”

Those features appear to be glacial debris whose surface alternates between peeling gaps and the unique Martian geology dubbed “brain terrain”, whose formation is not yet understood but is believed to be associated with near surface ice.

The location is indicated by the white rectangle on the overview map above. At 36 degrees north latitude, this crater is deep within that mid-latitude strip where a lot of glacial features are routinely found. If you look at the inset, you can see that all the nearby craters appear to have formed in what appears to be slushy ground, their rims not very pronounced or distorted and their floors shallow, as if the ground melted like ice upon impact but very quickly solidified.

Mars is not a dry place. Future colonists will likely build their first cities around 30 degrees latitude, close enough to the equator to get warmer temperatures, but close enough to the near-surface ice found just a few degrees poleward, in a place such as this.

Swarm satellite constellation detects changes in the Earth’s magnetic field during the past decade

Changes in the magnetic field over the northern hemisphere
Click for original graphic.

The European Space Agency’s three-satellite Swarm constellation, designed to measure the strength of the Earth’s magnetic field at high resolution, has found that the field’s weak and strong regions have shifted and changed in the past eleven years, since the constellation was launched.

The map to the right shows the changes over the northern hemisphere, related to the movement of the north magnetic pole towards Siberia.

[S]ince Swarm has been in orbit the magnetic field over Siberia has strengthened while it has weakened over Canada. The Canadian strong field region has shrunk by 0.65% of Earth’s surface area, which is almost the size of India, while the Siberian region has grown by 0.42% of Earth’s surface area, which is comparable to the size of Greenland.

Similarly, the Swarm data has shown the South Atlantic Anomaly, a major weak area of the field above South America near the equator, has grown significantly eastward towards Africa. That change is important for satellite operations, as spacecraft passing through it experience higher levels of radiation.

All these changes are thought to be because of shifts within the Earth’s molten core from which the dynamo of the magnetic field is generated.

New research confirms the steady decline of Martian ice with each glacial cycle

The obliquity cycles of Mars

Using orbital data from Mars Reconnaissance Orbiter (MRO) of glaciers inside mid-latitude craters, scientists have concluded that there was a steady decline in the growth of those glaciers with each new glacial cycle.

They focused on craters with indicative signs of glaciation, such as ridges, moraines (piles of debris left behind by glaciers), and brain terrain (a pitted, maze-like surface formed by ice-rich landforms). By comparing the shapes and orientations of these features with climate models, they found that ice consistently clustered in the colder, shadowed southwestern walls of craters. This trend was consistent across various glacial periods, ranging from approximately 640 million to 98 million years ago.

The results show that Mars didn’t just freeze once—it went through a series of ice ages driven by shifts in its axial tilt, also known as obliquity. Unlike Earth, Mars’ tilt can swing dramatically over millions of years, redistributing sunlight and triggering cycles of ice build-up and melting. These changes shaped where water ice could survive on the planet’s surface. Over time, however, each cycle stored less ice, pointing to a gradual planetary drying. [emphasis mine]

You can read the paper here [pdf]. This result is not new. Based on the orbital data scientists have theorized now for almost a decade that as Mars’ rotational tilt (its obliquity) swings from 11 to 60 degrees, it produces extreme climate cycles on the planet. Those swings are shown on the graph to the right, taken from this 1993 paper [pdf]. When the obliquity is low, the mid-latitudes are warm and the glaciers there shrink, with the snow falling at the poles. When obliquity is high, the poles are warmer and its ice sublimates away to fall as snow in the mid-latitudes, thus causing those glaciers to grow instead.

The orbital data has consistently shown that with each new cycle, the glaciers grew less, suggesting that less global water was available on the planet. This new study further confirms these conclusions.

One last point: Though the amount of water ice on Mars has declined, we mustn’t think the red planet now has none. The orbital data shows that there is a lot of near surface ice on Mars, covering the planet from 30 degrees latitude poleward. As I’ve noted numerous times, Mars is a desert like Antarctica.

New study claims the giant impact that created the Moon’s South Pole-Aitken Basin was oblique, from the south

South Pole-Aitken Basin
Click for original. Blue indicates the basin, red
the “thorium-rich and iron-rich ejecta deposit”

While previous work had suggested the giant bolide that had created the Moon’s South Pole-Aitken Basin came in from the north, a new study now proposes that the impact was instead oblique from the south. From the paper’s abstract:

The ancient South Pole–Aitken impact basin provides a key data point for our understanding of the evolution of the Moon, as it formed during the earliest pre-Nectarian epoch of lunar history, excavated more deeply than any other known impact basin, and is found on the lunar far side, about which less is known than the well-explored near side. Here we show that the tapering of the basin outline and the more gradual topographic and crustal thickness transition towards the south support a southward impact trajectory, opposite of that commonly assumed. A broad thorium-rich and iron-rich ejecta deposit southwest of the basin is consistent with partial excavation of late-stage magma ocean liquids.

These observations indicate that thorium-rich magma ocean liquids persisted only beneath the southwestern half of the basin at the time of impact, matching predictions for the transition from a global magma ocean to a local enrichment of potassium, rare-earth elements and phosphorus (KREEP) in the near-side Procellarum KREEP Terrane.

In other words, when this impact occurred, part of the impact site in the south was still a magma ocean.

This result, if confirmed, has research implications for the missions targeting the Moon’s south pole. It suggests the geology will have that KREEP materials readily available, which will provide important information about the Moon’s early geological history.

Martian winds are faster than expected

According to an analysis of pairs of 300 hundred orbital images taken seconds apart, scientist have found that Martian winds can reach speeds of 100 miles per hour (160 kilometers per hours), much faster than previously expected.

The results show that the dust devils and the winds surrounding them on Mars can reach speeds of up to 44 m/s, i.e. around 160 km/h, across the entire planet, which is much faster than previously assumed (previous measurements on the surface had shown that winds mostly remain below 50 km/h and – in rare cases – can reach a maximum of 100 km/h). The high wind speed in turn influences the dust cycle on the Red Planet: “These strong, straight-line winds are very likely to bring a considerable amount of dust into the Martian atmosphere – much more than previously assumed,” says Bickel. He continues: “Our data show where and when the winds on Mars seem to be strong enough to lift dust from the surface. This is the first time that such findings are available on a global scale for a period of around two decades.”

You can read the paper here. The study also found dust devils favor the spring and summer in both the north and south hemispheres, and tended to be concentrated in the mid-latitudes.

What is most interesting about this data, which because it is somewhat sparse has a lot of uncertainties, is that it suggests the candidate landing zone for SpaceX’s Starship is a region with one of the most intense dust devil seasons every spring and summer. This is not really a threat to settlement, because the atmosphere is so thin even these high winds would hardly be felt, but it does indicate an environmental condition that must be considered for any future settlement there.

Fresh slope streak on Mars

Fresh slope streak on Mars
For original images go here and here.

Cool image time! One of the geological mysteries on Mars seen no where on Earth is something scientists have dubbed “slope streaks.” Though they at first glance appear to be avalanches, they do nothing to change the topography, have no debris pile at their base, and sometimes even travel up and over rises on their way downhill. They can also appear randomly throughout the year, can be bright or dark, and fade with time.

No theory as to their cause has yet been accepted, though recent research suggests they are dry events, dust avalanches triggered by dust devils, wind, or the accumulation of dust.

To better understand this geology, scientists repeatedly monitor known slope streak locations looking for changes. The two images to the right are an example, downloaded from the high resolution camera on Mars Reconnaissance Orbiter (MRO) on July 2, 2024 and September 1, 2025. In the fourteen months that passed between the first and second images, two distinct and large slope streaks occurred next to each other, near the bottom of the picture. All the other streaks merely faded.
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Modeling suggests Uranus’s moon Ariel needed underground oceans to shape its known surface

Ariel as seen by Voyager-2 in 1986
Ariel as seen by Voyager-2 in 1986.
Click for original image.

The uncertainty of science: Using computer modeling based on our scant data of the surface features of the Uranus moon Ariel, scientists now posit that underground oceans, some of gigantic depth as much as 100 miles deep, were required to shape those features.

“First, we mapped out the larger structures that we see on the surface, then we used a computer program to model the tidal stresses on the surface, which result from distortion of Ariel from soccer ball-shaped to slight football-shaped and back as it moves closer and farther from Uranus during its orbit,” Patthoff said. “By combining the model with what we see on the surface, we can make inferences about Ariel’s past eccentricity and how thick the ocean might have been.”

The team found that, in the past, Ariel needed to have an eccentricity of about 0.04 [to create those surface structures]. This is about 40 times larger than its current value. While 0.04 may not sound dramatic, eccentricity can strengthen the effects of tidal stresses, and Ariel’s orbit would have been four times more eccentric than that of Jupiter’s moon Europa, which is wracked by the tidal forces that push and pull it to create its cracked and broken surface. Yet, to the eye, the orbit will still resemble a circle.

“In order to create those fractures, you have to have either a really thin ice on a really big ocean, or a higher eccentricity and a smaller ocean,” Patthoff said. “But either way, we need an ocean to be able to create the fractures that we are seeing on Ariel’s surface.”

This result does not prove an underground ocean now exists, or even if one existed in the past. The data is based on the few fly-by images taken by Voyager-2 when it passed close to Uranus in 1986. Coverage of the entire surface of Ariel was not complete, nor did the images have much resolution. The data is suggestive of this conclusion, but not conclusive by any means.

New study finds ice is better at dissolving iron than liquid water

In a result that could have a direct bearing on trying to understand the inexplicable geology of Mars, a new study has found that ice actually does a better job at releasing iron from mineral deposits than liquid water.

It was once believed that when iron-rich mineral deposits were locked in ice, the iron would stay put, but a new study from Sweden’s Umeå University shows that the ice itself is actually working better than permafrost melt to release the iron. The study showed that ice at -10 °C (14 °F) releases more iron from mineral deposits than liquid water at 4 °C (39.2 °F). “It may sound counterintuitive, but ice is not a passive frozen block,” says study co-author Jean-François Boily. “Freezing creates microscopic pockets of liquid water between ice crystals. These act like chemical reactors, where compounds become concentrated and extremely acidic. This means they can react with iron minerals even at temperatures as low as minus 30 degrees Celsius.”

The researchers also found that the seasonal freeze/thaw cycle helped this process, and that brackish fresh water did better in dissolving the iron than seawater.

The significance for Mars geology is that this suggests glacial ice in the alien Mars climate might be the catalyst for creating its meandering canyons that so much resemble features on Earth produced by liquid water. On Mars however no model yet has been convincingly successful in creating past conditions where liquid water could flow on the surface. Mars has either been is too cold or its atmosphere too thin to allow it.

This study suggests ice however could do the work. It also fits with other Martian data that suggests the same, that at the base of the Martian glaciers pockets of liquid water could exist that act to shape the canyons.

All of this is speculation on my part, but it seems that the planetary scientists who are studying Mars should take a close look at this research.

A Martian landscape of volcanic pimples

A Martian landscape of volcanic pimples
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and downloaded on August 3, 2025. Labeled as a “terrain sample,” such images are usually taken not as part of any specific research request but because the camera team needs to fill a gap in the camera’s schedule so as to maintain its proper temperature. When they do this, they always try to pick interesting targets within the time window, and usually succeed.

In this case, the camera team picked a location in the middle of Isidis Planitia, one of Mars’ four biggest basins thought to have been formed from a major impact several billion years ago, focusing on an area covered with these strange knobs that have craterlike depressions at their peaks.

According research published in 2010 [pdf], it is believed these cones — all of which are only a few feet high — are the result of volcanic activity following the impact that formed Isidis four billion years ago. In a sense, they are leftover pimples from that impact and the subsequent volcanic activity within that melted basin.
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Blobby Martian crater filled with ice

Overview map

A blobby Martian crater filled with ice
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 4, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this a “concentric fill crater,” a term used by planetary scientists for Martian craters that appear to be filled with glacial material. That certainly appears to be the case, but this 3.5-mile-wide unnamed crater also appears to have been warped by the ice that impregnates the ground all around it.

The overview map above explains why. The white dot marks the location, on the eastern end of the 2,000-mile-long northern mid-latitude strip that I label glacier country, because almost every image in this region shows similar glacial features. Though it is hard to tell from the inset, all the craters here have similar glacial material within them, and the ground surrounding them also appears glacial in nature.

This particular location is at 40 degrees north latitude. While it might be difficult to establish a colony here, on ground that appears so unstable, going 700 to 800 miles to the southeast would put you in what is considered one of Mars’ prime mining regions. Thus, with the right equipment mining operations would have accessible water not that far away.

Monitoring the largest recent impact detected by InSight’s seismometer

Overview

Cool image time! On December 24, 2021 the seismometer of the Mars lander InSight detected a four magnitude earthquake, the largest detected up until then. Because its nature suggested that it had been caused by an impact, not an internal shifting, the science team for Mars Reconnaissance Orbiter (MRO) immediately started searching for new impact craters in the area of Mars where the data suggested the quake came from.

Two months later they found it, in the northern lowland plains just south of the prime landing zone chosen by SpaceX for its Starship spacecraft. The black cross on the overview map to the right indicates the position. The four red spots are the prime Starship landing sites. The white dots indicate other locations considered. The black dots were images taken for a proposed Dragon landing. This impact is thus only about 100 miles away from the nearest possible Starship landing spot.
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Bubbling lava frozen in a Martian crater

Bubbling lava frozen 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 June 23, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). This one-mile-wide unnamed crater was a featured image last week by the science team. As noted in the caption, written by Chris Okubo of the U.S. Geological Survey:

This area was covered by a large flood of lava, which we see as the generally flat areas surrounding the crater. As the lava flowed across, some of it flowed into this crater through a low spot along the crater rim.

Once in the crater, the lava heated ground water or ground ice in the floor, causing the water to boil and turn into steam. This steam then exploded through the overlying lava and created small, ring-shaped formations. These are called ”rootless cones,” and they record the presence of ground water or ground ice in the crater floor at the time of the lava eruptions.

In other words, when this crater was flooded with hot lava, it was filled with ice or water. That fact is significant because of the crater’s location, as shown in the overview map below.
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Has Curiosity stumbled upon a small slope streak?

Is that a slope streak in the lower right?
Click for original.

Overview map
Click for interactive map

In reviewing the pictures downloaded today by the Mars rover Curiosity, I noticed something very intriguing in the pictures taken by rover’s two navigation cameras. One such picture is above, taken by the right navigation camera and looking west across the boxwork ridges that Curiosity has been traversing for the past two months. You can see two such ridges in the right foreground, cutting diagonally from left to right.

The overview map to the right gives the context, with the blue dot marking Curiosity’s position. The white and red dotted lines indicate its actual and planned routes respectively, with the top inset zooming in to show the recent travels more clearly. The yellow lines show the approximate area covered by the picture above.

Note the dark streak in the lower right of the picture. The bottom inset on the overview map shows this streak more closely. To my eye, it strongly resembles a slope streak, a strange geological feature unique to Mars.

If I am right, expect the rover team to focus in on this streak. The cause of slope streaks remains unknown. From orbit, the streaks look like avalanches at first glance, but they don’t change the topography, have no debris pile at their base, and sometimes even travel up and over rises as they head downhill. They can occur randomly throughout the year, can be bright or dark, can occur anywhere, and fade with time.

There are a number of theories (see here, here, and here) attempting to explain their cause, but none has been confirmed. If this is a streak, it will be the first that any scientist can see up close.

It is also very likely my guess is wrong, and this is not a streak. Stay tuned for updates.

Patterned frozen lava in Mars’ volcano country

Patterned frozen lava
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on May 31, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team label this “patterned ground.” And it is indeed. Though the topography is almost flat for large distances, the ground itself has these various patterns on it, from meandering small ridges to stippled roughness to very smooth sections.

The location is at 4.6 degrees north latitude, in the dry equatorial regions of Mars. No near surface ice created these features. All we can deduce from this picture is that this landscape is relatively young, as there are no craters seen.

So what caused these features? The location as always provides a clue.
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“What the heck?!” glaciers on Mars

Overview map

Another
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 29, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It falls into what I call my “What the heck?!” category of Martian land-forms, simply because their shape is so strange and inexplicable it is difficult to conceive a geological process that could create them.

Nor does it help much that we know what these land-forms are made of. The white dot on the overview map above marks the location, inside the 2,000-mile-wide northern mid-latitude strip I label glacier country, because almost every image taken shows glacial features. In this case, this strange geology is located on the floor of a canyon that is part of a large region of chaos terrain, a landscape typical of glacier country. This floor, as well as all the low areas, seems filled with glacial flows. This particular canyon appears to roughly flow downhill to the northwest, though the downhill grade in the entire region varies widely in all directions.

Based on all the orbital data, these flows are glacial in nature, the ice protected by a thin top layer of dirt and debris. The strange features at the top of all the small mesas in the picture above suggest that the wind possibly blew off the dirt and debris, exposing the ice and allowing it to sublimate away. This in turn produced the knobby hollows at the top of each mesa.

I am guessing, and no one should trust my guess considering I only make believe I’m a geologist on the internet.

Perseverance looks west

Perseverance looks west
Click for full resolution. For original images go here and here.

Overview map
Click for interactive map.

Cool image time! The panorama above, reduced and sharpened to post here, was created using two pictures taken on August 28, 2025 by the left navigation camera on the Mars rover Perseverance (here and here).

The blue dot on the overview map to the right marks Perseverance’s location when it took these pictures. The yellow lines indicate the approximate area covered by the panorama. The red dotted line indicates the rover’s planned route, with the white dotted line its actual travels.

The recent geological research focused on the lighter-colored ridge on the right center, dubbed Soroya. From the August 27, 2025 update by the science team:

Soroya was first picked out from orbital images as a target of interest because, as can be seen in the above image, it appears as a much lighter color compared to the surroundings. In previous landscape images from the surface, Mars 2020 scientists have been able to pick out the light-toned Soryoa outcrop, and they noted it forms a ridge-like structure, protruding above the surface. Soroya was easily identifiable from rover images as Perseverance approached since it indeed rises above the surrounding low-lying terrain.

The view is looking downhill away from Jezero Crater. The curve of the horizon is an artifact of the navigation camera’s wide view, accentuated by the slope that the rover sits on. The low resolution of this western region on the overview map is because the science team has not yet had Mars Reconnaissance Orbiter (MRO) get highest resolution pictures there yet.

Note the utter barrenness of this terrain. This is Mars, a lifeless world that has only the future potential for life, once we humans start to colonize it. Whether there was ever any past life remains uncertain, but the nature of its terrain as seen by both Perseverance and Curiosity suggests strongly that past life never existed, or if it did it barely survived and was quickly wiped out, a long time ago.

Another great hiking location on Mars

Another great hiking location on Mars
Click for original image.

In honor of our just completed visit to the south rim of the Grand Canyon, today’s cool image takes us to another location on Mars that to me appears a perfect place to install some hiking trails. The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 30, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The image shows a two-mile wide canyon with a number of scattered narrow mesas within. The north and south rims rise about 550 feet above the canyon floor. The two mesas labeled “A” and “B” rise about 200 and 100 feet respectively.

The hiker in me immediately imagines what a great hike it would be to go up the western nose of either ridge and walk along its crest. The knife-edge nature of ridge “A” would mean that for a large majority of the hike you’d be at the north and south edges at the same time.
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Sand dunes inside the Martian north polar icecap

Sand dunes inside the Martian north polar icecap
Click for original image.

Today’s cool image returns to the Martian north pole. The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on July 3, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the top of a ridge near the edge of that icecap, with dunes visible in the hollow several thousand feet below.

The angle of this picture does not show us the many layers on the cliff leading down to those dunes. It does show evidence, however, of the top few layers on the flat crest of that ridge. The white lines delineate those layers, each line marking the edge of a series of wide terraces.

The dunes in the canyon below are of interest because their source is likely the dust that is mixed into thick icecap’s ice. As that ice sublimates away on the face of the cliff, the dust falls into the canyon, where it is trapped.
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The beauty of Mars’ many-layered northern icecap

The beauty of Mars' ice cap
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 1, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels it clumsily as “North Polar layered deposits structural geology in icy layers”. What we see are the many layers that make up the north polar cap, produced by the red planet’s many climate cycles that scientists think Mars has undergone over the eons as the red planet’s rotational tilt, or obliquity, rocked back and forth from 11 degrees inclination to as much as 60 degrees. At the extremes, the ice cap was either growing or shrinking, while today (at 25 degrees inclination) it appears to be in a steady state.

These layers are a mixture of ice and dust. The variations from dark to light likely indicate changes in the amount of dust in the atmosphere. Dark layers suggest the atmosphere was more dusty due to volcanic eruptions. Light layers suggest the planet’s volcanic activity was more subdued.

At least that’s one hypothesis.
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Wind-eroded terrain on the edge of Mars’ largest volcanic ash field

Wind-eroded terrain in Mars' largest volcanic ash field

Cool image time! The picture to the right, cropped and sharpened to post here, was taken on July 2, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Labeled simply as “wavy terrain” by the MRO science team, it shows a relatively flat plain of hollows and terraced ridges that suggest the prevailing winds come from the west-southwest. As they blow, they slowly cause the layers of material to peel away, exposing those terraces.

This wavy landscape extends for many miles to the west, covering a region 135 by 160 miles in area. The layering and wavy nature of the terrain suggests the material here is fragile and easily peeled away by the winds of Mars’ very thin atmosphere. Think of the sandstone that forms Monument Valley and Canyonlands in the southwest United States, shaped almost entirely by wind.

And in fact, the overview map below confirms this.
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Slumping landslide in Mars’ glacier country

Overview map

Slumping landslide in Mars' glacier country
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was downloaded on July 1, 2025 from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Labeled by the science team as a “flow,” it shows what appears to be a major collapse of the canyon’s south wall. The white dot on the overview map above marks the location, near the center of the 2,000-mile-long strip in the northern mid-latitudes of Mars that I label “glacier country” because almost every single high resolution image of this region shows glacial features.

This picture is no exception. First, the canyon appears filled with a glacial material, though its flow direction is unclear. Orbital elevation data suggests that this collapse is actually at the canyon’s high point, with the drainage going downhill to the east and west.

Second, the collapse itself doesn’t look like an avalanche of rocks and bedrock, but resembles more a mudslide. Since liquid water cannot exist in Mars’ thin atmosphere and cold climate, the soft nature of the slide suggests it is dirt and dust impregnated with ice. At some point, either because of the impacts that created the craters on its southern edge or because the sun warmed the ice causing it sublimate away thus weakening the ground structurally, the entire cliff wall slumped downward to the north.

The canyon itself is about 800 feet deep. It likely formed initially along a fault line, with ice acting over time to widen and extend it.

Gullies on a crater wall in the icy north of Mars

Gullies on a crater wall
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 4, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the lower right quadrant of a five-mile-wide unnamed crater in the high northern mid-latitudes of Mars.

The science team in its label for this picture focuses on the gullies visible on the crater’s interior wall. To my Earth-bound eye, these gullies look like recent erosion caused by underground ice sublimating into gas, causing the surface to collapse downward into the crater. This however is a purely uneducated guess.

The floor of the crater however shows features that resemble glacial fill, seen in numerous high latitude craters on Mars. This is not surprising, as the crater is located at 59 degrees north latitude, close enough to the pole for there to be a lot of near surface ice to be present.
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Slope streaks within Mars’ largest mountain region

Overview map

Today’s cool image revisits Lycus Sulci, the largest mountain range on Mars, about 1,400 mile wide and 1,800 miles long. The overview map to the right gives a sense of the roughness and chaotic nature of this region, extending north from Mars’ largest volcano, Olympus Mons.

At present scientists are unsure of the geology that formed Lycus Sulci, and how it is linked with Olympus Mons. The wide view to the right suggests it is the remains of a very ancient lava flow descending from the volcano that over time has become eroded to produce this wildly knobby terrain. That hypothesis remains unproven however. There is also evidence that the material here might instead be volcanic ash, deposited in many layers and eroded away with time.

The location of the cool image below is marked by the white dot, with the inset providing us a wider view of the surrounding terrain. Note the two craters to the north and west. Both appear to have been partly filled by flows coming from the south and east, respectively, adding weight to the theory that this region formed from lava flow.
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When Martian lava meets a Martian mountain

When Martian lava meets a Martian mountain
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on April 24, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and was posted yesterday by the science team to illustrate the vast lava flows that cover much of Mars. From the caption:

This image captures the edge of a lava flow that partially buries older terrain in the Martian Southern Highlands. Where the edge of the lava flow made contact with the higher-standing topography, it formed a rumpled and ridged surface.

This lava flow is one of many massive flows that extend southwest from Arsia Mons, one of the largest shield volcanoes on Mars.

The mountain to the south rises about 3,700 feet above that rumpled lava ocean at its base.
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Strange rocks on Mars

Coral on Mount Sharp!
Click for original image.

Float rock in Jezero Crater
Click for original image.

Time for two cool images, from two different craters separated by thousands of miles on Mars! The first image to the right, cropped, reduced, and sharpened to post here, was taken on July 24, 2025 by the Mars Hand Lens Imager (MAHLI) at the end of the robot arm of Mars rover Curiosity, and shows a really strange rock formation that resembles a piece of coral on Earth.

Curiosity has found many small features like this one, which formed billions of years ago when liquid water still existed on Mars [in this region]. Water carried dissolved minerals into rock cracks and later dried, leaving the hardened minerals behind. Eons of sandblasting by the wind wore away the surrounding rock, producing unique shapes.

The second image, cropped, reduced, and sharpened to post here, was taken on August 5, 2025 by the left high resolution camera on the rover Perseverance. It shows what appears what geologists call a “float rock”, something that was created geologically somewhere else and transported to this location later.

In this case the rock appears lavalike in nature. Since Perseverance is exploring the exterior rim of Jezero Crater, we could be looking at the impact melt created when the bolide hit the ground to create the crater. Material would be instantly melted as well as flung outward as ejecta, with this strangely shaped rock an example.

The problem with this theory however is that the rock appears to have solidified well before it hit the ground at this location. Its shape also suggests it solidified within a crack, thus molding it to this shape, with its top once at the bottom, the lava flowing downward. The mystery then is how it ended up as we see it, upside down and exposed.

Curiosity looks back

Curiosity looks back
Click for original image.

Cool image time! The picture to the right, reduced and enhanced to post here, was taken on July 28, 2025 by the left navigation camera on the Mars rover Curiosity. It looks to the north, down the flanks of Mount Sharp and across the floor of Gale Crater to its mountainous rim about 30 miles way, seen on the horizon.

The view is so clear because of the season, as noted in the science team’s blog post today:

We’re still in the time of year where the atmosphere at Gale is reasonably dust-free (at least, compared to later in the year), allowing us to look all the way out to and beyond the Gale crater rim. The upper slopes of Mount Sharp have also re-emerged to our east after spending months hidden behind the walls of Gediz Vallis. There’s a bit more sand and dust in this location than we’ve seen recently, so we can also see the trail left behind by the rover’s wheels as we drove to this location

The ridge in the foreground is an example of the boxwork Curiosity is presently traversing. It is now on one of those ridges, and will be moving along it in short drives as the science team studies the geology here. The rover’s tracks leading up to this position can be seen clearly.
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