Tag: exploration

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows one small area in Martian equatorial regions where the main features are a dusty plain interspersed with craters, not entirely dissimilar to the Moon .

In the picture the northwest-to-southeast orientation of ridge-lines, plus the position of divots with their steep and deep end all on the northwest side, all suggest the prevailing winds here blow in the same direction, from the northwest to the southeast.

We are looking at a very ancient terrain. Many of these craters likely date from the early bombardment period of the solar system, just after the planets had formed but there was still a lot of objects around crashing into them.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on March 24, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) as part of a long term monitoring program of the many Martian gullies scientists have found above 30 degrees north latitude on a variety of slopes.

Martian gullies are small, incised networks of narrow channels and their associated downslope sediment deposits, found on the planet of Mars. They are named for their resemblance to terrestrial gullies. First discovered on images from Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a dendritic alcove at its head, a fan-shaped apron at its base, and a single thread of incised channel linking the two, giving the whole gully an hourglass shape. They are estimated to be relatively young because they have few, if any craters.

…Most gullies occur 30 degrees poleward in each hemisphere, with greater numbers in the southern hemisphere. Some studies have found that gullies occur on slopes that face all directions; others have found that the greater number of gullies are found on poleward facing slopes, especially from 30° to 44° S. Although thousands have been found, they appear to be restricted to only certain areas of the planet. In the northern hemisphere, they have been found in Arcadia Planitia, Tempe Terra, Acidalia Planitia, and Utopia Planitia. In the south, high concentrations are found on the northern edge of Argyre basin, in northern Noachis Terra, and along the walls of the Hellas outflow channels.

Orbital data has identified almost 5,000 gullies on Mars. Based on their shape and the Martian climate, scientists generally think these gullies were formed by some form of water flow, possibly coming from an underground aquifer at their top.
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Today’s cool image illustrates the complex explanations scientists sometimes have to come up with explain the strange geology seen on Mars. The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a whitish “ridged flow-like feature” that appears to exit out of the massive hill to the west.

The white dot on the overview map above as well as in the inset marks this location, smack dab inside the 2,000-mile-long strip of glacier country in the Martian northern mid-latitudes. As you can see from the inset, that massive hill is actual the foot of a large apron of material, likely ice-infused, that has sagged down from the large 5,400-foot high mesa to the west.

The white material is likely what the scientists call an inverted river. Once it was a channel in which either water or ice flowed. With time the weight of that material compacted the riverbed so that it was denser than the surrounding terrain, much of which was likely soft anyway because of a high ice content. When that surrounding terrain eroded away, the riverbed resisted that erosion, and instead became the raised ridge we now see.

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Cool image time! The picture to the right, rotated, cropped, and sharpened to post here, was taken on May 14, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small section of a vast dune field, 50 miles square, that sits about 225 miles south of the southern foothills of Mars’ biggest volcano, Olympus Mons.

The dunes are probably less than 20 feet high, with that one small hill only slightly higher. Their similar orientation, which extends across the entire 50-mile-square dune field, indicates the direction of the prevailing winds, which I think (but will not swear to it) is from the southeast to the northwest, which also happens to also follow the grade downhill to the northwest.

It is also possible that wind direction is the reverse, and goes uphill to the southwest.
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It is time for two cool images! The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 10, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and is one of two glaciers imaged by MRO in May that are among a whole series of glaciers flowing down the south wall of the same mesa.

The red dot in the inset and on the overview map above marks the location of the picture to the right. The white dot marks the location of the May 27, 2023 picture, which can be seen here.

The unnamed 10,000-foot-high mesa from which these glaciers flow, located in the middle of the 2,000-mile-long northern mid-latitude strip I dub glacier glacier country, is about 41 miles long and 18 miles wide at its widest point. The glacier to the right falls about 6,000 feet in about four miles, making the grade steep, ranging from 15 to 23 degrees. That steepness explains the split in the glacier, as it flowed around a huge piece of higher bedrock in the middle of this descending hollow.

Both images provide further evidence of the dominance of glaciers in this mid-latitude region. While the glaciers are all covered with dust and debris to protect the ice, and are also thought at present to all be inactive, they also all suggest a very dynamic Martian geological and climate history, one that will likely come alive again as the planet’s rotational tilt naturally shifts back and forth from its present 25 degree tilt to 11 to 60 degrees.

The glaciers also show us again that Mars is not a dry desert, but above 30 degrees latitude it is an icy desert much like Antarctica. Colonists will have no trouble finding water.

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on March 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

In labeling this picture the science team focused on the many layers visible in these swirls, all suggesting a series of cyclical events, each laying down a new layer over many eons.

What caused the swirls? Looking at the lower right quadrant it appears that they were glacial, with the flow to the northwest but with each glacial layer smaller and not reaching as far.

This theory falls apart however at the curved depression, which instead suggests the swirl was traveling along a meandering canyon, going from the lower left to the upper right. If so, the curved depression is even more baffling. If ice it could have sublimated away, but its sharp edges suggest this isn’t ice but maybe a lava flow.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on May 25, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The scientists describe these cones as “longitudinally aligned cones,” but this is puzzling since the alignment runs from the northwest to the south east, not north-south along the longitude.

No matter. The alignment is in itself the mystery, especially because the full image shows many more strings of cones in this area, all running from the northwest to the southeast. The strings also are all curved in the same way, sagging to the southwest as if expressing a wave flowing in that direction.

What could create these strings of cones? The overview map below gives us a hint.
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Today’s cool image illustrates the once violent and active volcanic past of Mars, now long dormant. The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 11, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a “vent and channel” located high on the northeast flanks of the giant volcano Arsia Mons.

The rim around the vent suggests that lava had once bubbled up out of the vent and hardened around it, as most of the lava flowed downhill along the channel. And though this vent appears to be the source of this channel, it is not. The channel continues to the southwest uphill until it reaches the edge of Arsia Mons’ caldera, a region where there are many such vents, many much larger and deeper than this one.
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Cool image time! The picture to the right, rotated, cropped, rotated, and sharpened to post here, was taken on June 3, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the eastern half of a six-mile-wide unnamed crater with a depth of about 1,500 to 2,000 feet from rim to floor.

What makes this picture significant is the patchy material in the center of that crater floor, some of which looks almost like very old peeling paint. It also resembles the kind of glacial features routinely seen in many craters poleward of 30 degrees latitude on Mars.

Is this another example of such glacial features? If so, its location is what makes it significant.
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Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on April 18, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows only one of many flat-topped mesas in a chaos terrain region dubbed Oxia Chaos.

The mesa top is about 540 feet above the floor of the canyon to the north, which in turn is about 840 feet below the flat terrain north of it. That flat terrain to the north is not part of the chaos terrain, however, but the northern rim of the plateau that surrounds the chaos. Moreover, this particular piece of rim is separating from the plateau, as shown near the top of this January 16, 2008 context camera image from MRO. At some point in the future it will break off and fall into that canyon and on top of this mesa.
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on April 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the rim of a seventeen-mile wide crater, and was the scientists label a “gully without apron,” meaning that though something has caused material to disappear within that gully, beginning high on the rim wall, there does not appear to be any piled up apron or debris at the gully’s base.

The blue colors imply the possibility of frost within the gully, while the orange suggests dust or coarse surface material.

The cracks emanating away at right angles from the gully’s base suggest glacial ice, which makes sense based on the location.
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In looking through new images from Mars Reconnaissance Orbiter (MRO), I sometimes stumble some very strange things, with today’s cool image an example. The picture to the right, rotated, cropped, and reduced to post here, was taken on May 7, 2023 by MRO’s high resolution camera, and shows the western half of a two-mile-wide crater with a very weird rim, almost as if a person had decided he wanted to reshape it with a filigree pattern.

Though only two-miles wide, this crater actually has been named Johnstown. I suspect this is because of its strange rim, prompting a research effort and the need to provide it a name. Why the rim has this repeating pattern of gaps, however, is beyond my pay grade to explain, and I have been unable to track down any research papers about it. The nearby surrounding surface suggests vaguely the possibility that this is a caldera, not an impact crater, but even so why would the rim of the caldera have these regular breaks?
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