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SpecialSetOfSieves

SpecialSetOfSieves@lemmy.world
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Yep, that’s the exact term used by some planetary geologists since this kind of terrain was first seen in 2004. On this mission they’ve been quite common as well, starting with the very first abrasion/sampling site, among many others.

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New images up - just a few NavCam shots, but we can see that the coring bit has been withdrawn from the hole. Good news, it would seem.

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Multiple sols with no public data from Percy. Is it too soon to say “I have a very bad feeling about this”?

I’m glad that we’re still seeing fresh data from Curiosity on the server. There’s a lot of stuff to absorb from this mission, especially if you’re me, but it does help my workflow throughout the day to see the latest from Jezero. No speculation here, just sad vibes.

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Two sols have passed, and the coring drill is still embedded inside the rock…

I’m assuming this isn’t intentional. Paul, do you recall something like this ever happening before? If the rover encountered some kind of fault, it makes sense that they would leave everything where it is and assess the problem before acting.

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Not onboard the rover, no - which is one of the reasons many hardcore types are obsessed with sample return, in spite of the cost and extreme technical difficulty.

A number of age estimates for stuff in this area (the Jezero crater itself, the old mudstone down in the river delta we sampled last year, and so on) put them at easily 3.5 billion years plus - possibly older. That means the samples Perseverance already has in hand could be just as old as, or even older than, the most ancient sedimentary rock we’ve found on Earth. I get chills thinking about it.

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Always so strange and wonderful to see how these objects, entirely free of atmosphere or storm, can have such a “soft” look - with craters seemingly buried under a layer of snow or paste, or something. I wonder if that would be that be due to the phenomenon of regolith moving via “seismic shaking”, which is supposed to partially bury smaller features in these asteroid landscapes. Even these preliminary images have enough detail and apparent features to beguile the eye.

DJ definitely doesn’t appear as “soft” as Deimos or Atlas (out by Saturn), but those two moons are quite a bit larger than this inner main belt asteroid. A lovely reminder that there’s a lot to see in the Belt.

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You’re not wrong about this thing being bombarded by tiny collisions, but we should note that the impacting bodies that made the craters visible in these images were a lot larger than dust or sand grains. It’s not surprising to see an object like this, within the asteroid belt, covered in simple bowl-shaped craters. From what the New Horizons probe to Pluto and the Kuiper Belt has seen, however, even dust grains are actually pretty sparse in the outer solar system. Even if there actually is a “second Kuiper Belt” as some of the NH team proposes, it isn’t that dusty. In interstellar space, I would expect dust grains to be even rarer, let alone sand or pebbles.

That being said, interstellar probes will definitely need some form of protection from hypervelocity impacts, however rare they may be. That’s one good reason we should be looking seriously at more modest (and more feasible) proposals for spacecraft that will reach large but attainable distances beyond the heliosphere (say, 75 billion kilometres out from the Sun). The best way to verify the dustiness of nearby interstellar space is to measure it directly. Scouts have their value.

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We do these abrasions on the rocks before we start analyzing them in detail with the science instruments.

The geologists prefer not to analyze the raw, eroded outer surfaces of rocks - they tend to be covered in dust and sand, and they’ve been eaten away by the wind, or even (over long timescales) the minor amounts of humidity in the Martian atmosphere. By grinding away the outer surface, the fresh, unaltered interior of the rock is exposed.

The instruments then let you learn what minerals and other materials are in the rock, hopefully allowing us to ID what we’re looking at. If the instruments turn up interesting results, the science team may decide to take a sample of the rock for eventual return to Earth.

Hope this helps. Feel free to ask if I wasn’t clear about something.

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If you will pardon the late reply:

From what I can see, the colour image featured in this post is not vertical - it’s actually a close-up image from the microscope on the end of the rover’s robotic arm, which you can see placed over the target in this image, taken less than an hour after the microscopic image. The slope on which this rock/outcrop is found is well below 45º, or the rover’s wheels wouldn’t be resting on it. You can see a wider view of the rock adjacent to the target in this image from the same sol (if you’re interested, here are all the images taken on sol 4513).

That being said, your question is pertinent. Yes, I would call them layers also. There has clearly been deposition here - a lot of it - but erosion has shaped the landscape here in interesting ways too (this latter image was also taken on 4513).

The thing about folding is that it doesn’t occur in insolation, or only in very small areas; it’s generally a response to forces that act on regional scales. If there were folding at the rover’s current location, it would likely be visible in the surrounding countryside, including possibly on the towering layered ridges that now surround the rover.

Even for geologists, this field site makes you think.

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I just want to make sure I understand what/how you’re seeing this, I hope you don’t mind:

When you say you’re seeing vertical structure, are you talking about those protruding (and rather phallic) parts in the upper half of the image?

EDITED TO ADD image with relevant features outlined in yellow:

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