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Fresh washes on Mars?

Meandering fresh wash on Mars?
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on January 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels as “Fresh Shallow Valleys”. The section I have focused on shows a particularly interesting meander next to a small crater. The full image shows additional similar channels to the north, with one draining into a larger 3.7 mile wide crater.

The location is in the southern cratered highlands, at about 41 degrees south latitude, where much evidence of buried glacial features are found. That certainly is what we appear to see here. In fact, the wider view afforded by MRO’s context camera reveals many more such channels. That wider view also shows a much larger 18-mile-wide crater just to the north that appears filled with buried ice.

That the scientists label these fresh suggests they think they are relatively young, probably dating from when the most recent cycle of glacial growth probably ended. This would make them about 6 million years ago, based on this paper [pdf] and the second figure from that paper below.

The changing Martian inclination during the last 10 million years

According this graph, it appears Mars’ rotational tilt shifted from about 40 degrees to its present 25 degrees today about six million years ago. When it was 40 degrees the mid-latitudes would have been colder than the poles, and thus water would sublimate from the polar icecaps to fall as snow in the mid-latitudes. Glaciers would form there and grow, flowing down to carve channels such as these.

Since then those glaciers have been inactive. Scientists think (though this remains uncertain) that the poles and mid-latitude glaciers are presently in a steady-state, with neither growing nor shrinking.

Thus, any glaciers in these channels are likely stable at this time. No additional snow is falling on their upstream ends to the west, so they are under no pressure to flow eastward downhill.

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.

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