Tag: geology

More glaciers in Mars’ glacier country

2:24 pm

Overview map

glacial layering in Clasia Vallis
Click for full image.

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

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

Below is a wider view of Clasia Vallis, taken by the context camera on MRO on March 19, 2014.
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Zig-zag ridges on Mars

2:26 pm

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

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

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

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

The particular location, as shown on the overview map below, is close to the dry Martian equator, on the edge of Medusae Fossae Formation, the largest field of volcanic ash dust on Mars.
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Above ground and underground Martian drainages

2:28 pm

Overview map

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

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

Today’s cool image looks at the very intriguing meandering canyons that appear to flow south from Newton’s north rim.
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Watching DART impact asteroid on September 26, 2022

9:35 am

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

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

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

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

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

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Martian layers everywhere!

1:38 pm

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

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

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

The location of this canyon is also intriguing.
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Another model attempts to show how liquid water could have once existed on Mars

11:07 am

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

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

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

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

10:01 am

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

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

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

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

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InSight’s power level holding steady

9:57 pm

InSight's on-going power levels

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

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

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

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

Stay tuned. All is not yet lost.

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The strange scattered rocks of Gediz Vallis on Mars

10:28 am

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

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

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InSight’s seismometer detects its first new impact on Mars

1:13 pm

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

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

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

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

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

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

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Deep inside the youngest flood lava event on Mars

1:30 pm

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

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

In plain English, we are looking at a crater that has been inundated by the flood lava, filling it.
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The shattered cliffs of Mount Sharp

11:04 am

A broken cliff on Mars

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

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

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

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

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