Tag: science

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Today’s cool image is another example of what I call a “What the heck!” image. The picture to the right, simply cropped to post here, was taken on September 22, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows what the scientists label as “etched terrain,” an incredibly twisted and eroded landscape that to me actually defies description. In trying to research what scientists have learned and theorized about this terrain, it appears they think it is material that flowed over older terrain (thus its lack of many craters) that was subsequently eroded by later processes.

Why it eroded so strangely however is not really understood. It could have been caused by near-surface ice sublimated to the surface and thus causing many breaks, but since this terrain is located right on the equator in the dry tropics, it is a very long time since water was present here.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 9, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The white dot on the overview map above marks the location, inside the deep enclosed and very large 130-mile-wide depression dubbed Juventae Chasma.

The mountain in the picture raises above the sand sea that surrounds it from 1,000 to 2,300 feet, depending on direction, as the downhill grade of the sand sea is to the east. Thus, on the west the mountain rises less, while on the east the height is the greatest.

The inset illustrates the extent of the sand sea. It covers the ground for many miles in all directions. The way the sand surrounds these mountains suggests the prevailing winds blow from the west to the east. In fact, the facts suggest that this sand is volcanic ash that was blown into Juventae from many eruptions that occurred over time to the west, where it got trapped. The wind and gravity deposited the sand into the 20,000 to 25,000-foot-deep chasm, where the wind was insufficient to lift it out again.

One wonders how deep that sand sea might be. The lack of any surface features at all suggests it could be quite deep, burying everything but the highest peaks. In fact, if a geologist could drill a core through that sand I suspect he or she might be able to document the entire eruption history of much of Mars.

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 20, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labels the entire picture simply as “gully,” obviously referring to that distinct and somewhat deep hollow in the middle of the picture.

Most gullies that have been found on Mars tend to look more eroded and rougher than this hollow. Here, it appears almost as if the process that caused this gully occurred relatively recently, resulting in its sharp borders that have not had time to crumble into softer shapes.

The crater interior slope is about 1,500 feet high. Whatever flowed down it however did not do it in an entirely expected manner. As it flowed it curved to the west, so that the impingement into the glacial material that fills the crater floor is to the west of the gully itself. Either that, or that impingement was caused by a different event at a different earlier time.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 10, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

My reason to posting this I admit is selfish and tourist-oriented. This narrow ridge, about a mile long and about 300 to 600 feet high, appeals directly to my hiking passions. A trail along its length would provide any hiker some really spectactular views.

The scientists took the picture because of the geology. The white dot on the overview map above marks the location, a short channel dubbed Daga Vallis that connects two major canyons in the eastern part of Valles Marineris, the largest known canyon system in the solar system. This ridge and several nearby parallel ridges were apparently made of something, possibly lava, that was resistent to the theorized ancient catastrophic floods that scientists presently believe carved out these channels and canyons.

In the inset the dotted line indicates one possible hiking trail route that travels the full length of the ridge but then heads south to continue along the rim of a 1,200-foot-high cliff face. For future Martian colonists, I offer this site as a great place to set up a bed-and-breakfast, surrounded by many potential hikes of incredible stark beauty.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 17, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The white dot on the overview map above marks the location, inside a thirty-mile-wide dune sea, or erg, that sits in the center of the floor of 80-mile-wide Russell Crater.

That erg is interesting in that it appears the dunes get larger and larger as you move from the perimeter to its center. Thus, the dunes in the picture are called mega-dunes, about 200-feet-high. They dwarf the smaller dunes at the erg’s edge.

This picture was taken as part of a long term monitoring program to track the coming and going of seasonal dry ice frost on these dunes. It is summer when this picture was taken, so there is relatively little visible frost, though the bright blue areas in the color strip could possibly be the last remnants from winter. In winter, data suggests the entire surface of these dunes is covered by dry ice frost.

As the location is at 54 degrees south latitude, it likely sits at the northernmost edge of the southern dry ice mantle that in winter covers each of the Martian poles, down to about 60 degrees latitude.

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 16, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labels these strange features “ring-mound landforms,” a term that has been used to describe [pdf] only vaguely similar features previously found in the Athabasca flood lava plain almost on the other side of Mars. That paper suggested that those ring mounds formed on the “thin, brittle crust of an active fluid flow” created by an explosive event. Since Athabasca is considered Mars’s most recent major flood lava event, the fluid was likely lava, which on Mars flows more quickly and thinly in the lower gravity.

Thus, in Athabasca the ring-mounds formed when a pimple of molten lava from below popped the surface.

But what about the ring mounds in the picture to the right?
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 19, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely snapped not for any specific research project, but to fill a gap in the camera schedule in order to maintain its proper temperature.

When the science team does this they try to pick interesting locations. Sometimes the picture is relatively boring. Sometimes, like the picture to the right, it reveals weird geology that is somewhat difficult to explain. The picture covers the transition from the smooth featureless plain to the north, and the twisting and complex ridges to the south, all of which are less than a few feet high.

Note the gaps. The downgrade here is to the west, and the gaps appear to vaguely indicate places where flows had occurred.
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