APOD: Pluto: From Mountains to Plains (2015 Dec 14)

[APOD Robot]

Pluto: From Mountains to Plains

Explanation: What do the sharpest views ever of Pluto show? As the robotic New Horizons spacecraft moves into the outer Solar System, it is now sending back some of the highest resolution images from its historic encounter with Pluto in July. Featured here is one recently-received, high-resolution image. On the left is al-Idrisi Montes, mountainous highlands thought composed primarily of blocks of solid nitrogen. A sharp transitional shoreline leads to the ice plains, on the right, that compose part of the heart-shaped feature known as Sputnik Planum. Why the plains are textured with ice pits and segmented is currently unknown. The image was taken about 15 minutes before closest approach and shows an area about 30 kilometers across. The New Horizons spacecraft is next scheduled to fly past Kuiper Belt object 2014 MU 69 on New Year's Day 2019.

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[Ann]

That's an incredible image. I have to wonder what could have caused that sharp, sharp boundary between two incredibly different landscape types.

Ann

[monarchist2]

I don't understand why the interface here is being described as a "shoreline". The "mountainous" terrain is clearly a landslide of some sort, and has simply flowed out over the flat plain. Which may well have been liquid at some point. But this interface is not a shoreline.

[Chris Peterson]

I don't understand why the interface here is being described as a "shoreline". The "mountainous" terrain is clearly a landslide of some sort, and has simply flowed out over the flat plain. Which may well have been liquid at some point. But this interface is not a shoreline.

I think it is generally a good idea to not treat anything we see on planetary bodies other than our own as "clear", "obvious", or any similar description. We simply don't have enough information about what kind of processes might be involved in surface building, we don't know all the materials present, we don't know the nature of the interior, we don't know the impact history. This is a good time to maintain a very open mind.

[CuDubh]

Um, we do know many of the processes involved. We know the temperatures (low), the pressures (low), and to some extend the materials, (generally icy), we know the gravitational forces. And we know that the forces and chemistries are not fundamentally different than those on earth (at least in labs). And because of the chaotic nature of the area between the highlands and the basin (click on image to see full transect) we can infer that they were the result of a chaotic sliding process. Slower or more generally contractional processes create more regular features (fault systems, folds, thrust-fault controlled ramps and flats). And things tend to flow downhill. Even on Earth contractional features are ultimately attributable to things flowing downhill (e.g., plate tectonics).

Landslides have very, very, obvious morphology, and some of these ARE quite clearly they. They have a headscarp, variously rotated and translated blocks, hummocky terrain, and formerly semi-liquified material that flowed over a pre-existing surface. I would bet any sum of money that the lobe at top center is a landslide, and am pretty confident that it postdates (albeit perhaps only slightly) the fracture in the plain. The entire terrane has a fairly consistent expression and it requires no stretch of the imagination that it is the result of gravitational collapse. I'm not saying this is the truth, just that it is a very obvious and appealingly simple hypothesis, and my confidence comes from the fact that there are very, very similar features on earth and I don't expect to be proven wrong. This is a fairly chaotic result of materials moving downhill.

In the outer solar system we have mainly impacts, tidally-induced tectonics, and perhaps volcanism to create the sorts of gravitational "heads" (escarpments) to allow this sort of collapse to occur. The simplest hypothesis here would seem to be the gravitational collapse of the rim of a large impact basin. But I'm open to other explanations. But the chaotic lobate deposits really, really, resemble chaotic lobate deposits on earth, AKA landslides. You'll have to try a lot harder to convince me they aren't.

[Boomer12k]

Bizarre.....and Awesome.

:---(===) *

[Ann]

The simplest hypothesis here would seem to be the gravitational collapse of the rim of a large impact basin. But I'm open to other explanations. But the chaotic lobate deposits really, really, resemble chaotic lobate deposits on earth, AKA landslides. You'll have to try a lot harder to convince me they aren't.

Convincing you isn't our jobs.

Personally I'll wait for more reports from the scientists working on the mysteries of Pluto. But perhaps you are a scientist? A geologist? A hydrologist? Even an astronomer, perhaps an astronomer specializing on the icy bodies of the solar system? Perhaps you are even one of the NASA scientists working on the data from New Horizons?

Please tell us about your credentials.

Ann

[JohnD]

I have no credentials at all in this, but I love to speculate.
And on first seeing that picture, I thought, isn't that mountainous region (al-Idrisi Montes?) similar to the tectonic mountains on Earth? The area to the left is moving to the right and colliding with the flat Sputnik Planum. The wider view linked to at JPL http://photojournal.jpl.nasa.gov/catalog/PIA20213 shows that the Montes are at the rim of this ?plate? as it hits the Planum, raising mountains that erode and landslip, exactly as on Earth.

John

[batjac1@hvc.rr.com]

I'm not generally given to looking for this kind of thing, but...

On the right, there is a dark object in the center of what almost looks like a smooth path or "road". The "road" is sharp and distinct below this dark object, and although this path continues on above this object, it is much less sharply defined. It is as if this object is moving along this path from the bottom to the top, and smoothing it out as it goes.

Yeah, I know, but if this picture was from Antarctica, what would you surmise?

Sorry, it just looks unnatural to me.

[ygmarchi]

This is one of the most amazing pictures ever taken in the history of space exploration.
The lesson is that at different temperatures different materials can give rise to a geology comparable to that on Earth.
I wonder if there is the possibility of an alternative biology.

[JohnD]

batjac,
there's speculation and there's spectaculation.
"On the right" - could you be just a tiny bit more specific?

John

[Guest]

If you look at the right side of the image (Sputnik Planum), it appears as tho some of the fracture lines have been subject to some sort of liquid infill. But there also seems to be an 'erratic bolder' that is also very out of place and too far from the 'landslide area'. If it was some sort of long run-out landslide, I would expect to see a more extensive debris field. But a close look at the erratic, shows some evidence of liquid flowing around it. It made me wonder if Sputnik Planum was actually laid down on top of a 'rocky/mountainous surface' and the 'erratic' is actually a 'mountain' top poking thru the ice.

I also noted what appears to be impact craters in the 'landslide debris field' and some farther to the left of the margin of the 'landslide area'. But there are none that I can see in Sputnik Planum. That would hint that Sputnik Planum post-dates the 'landslide'. And it all looks very young compared to other surfaces in the solar system.

Is Pluto heated internally by some means, and is it really geologically active? Sub surface seas of liquid nitrogen, or something else?

The sad part is that you and I will never know what is really there beyond educated guessing... but guessing is entertaining...

[neufer]

I don't understand why the interface here is being described as a "shoreline". The "mountainous" terrain is clearly a landslide of some sort, and has simply flowed out over the flat plain. Which may well have been liquid at some point. But this interface is not a shoreline.

Click to play embedded YouTube video.

I think it is generally a good idea to not treat anything we see on planetary bodies other than our own as "clear", "obvious", or any similar description. We simply don't have enough information about what kind of processes might be involved in surface building, we don't know all the materials present, we don't know the nature of the interior, we don't know the impact history. This is a good time to maintain a very open mind.

[Steve Dutch]

That sure looks like a mega-slide to me. There's even a place where two lobes flowed out across the smooth "ice cap" and met, leaving a small "island" in between.

[Chris Peterson]

Um, we do know many of the processes involved...

Landslides have very, very, obvious morphology, and some of these ARE quite clearly they...

In the outer solar system we have mainly impacts, tidally-induced tectonics, and perhaps volcanism to create the sorts of gravitational "heads" (escarpments) to allow this sort of collapse to occur...

We know some processes. Landslides on Earth usually have obvious morphology, but even here we can be fooled. No morphology on Pluto is reasonably described as "obvious".

You'll have to try a lot harder to convince me they aren't.

I'm not all that interested in convincing you. My point remains. There's absolutely nothing wrong with speculation and with using known processes and landforms for comparison. But once I hear those comparisons overused to the point that someone is certain about what they're seeing on Pluto or some outer moon, I'm pretty sure I'm also seeing someone who's going to be eating their words in a few years.

[captainwiggins48]

Such a thought provoking image. Are those dunes on Sputnik Planum? Dunes imply wind. Here's my wild card: the last nearby super nova scoured half of Pluto, melting the nitrogen mountains and created a vast plain. Chuesz!

[Ron-Astro Pharmacist]

I don't understand why the interface here is being described as a "shoreline". The "mountainous" terrain is clearly a landslide of some sort, and has simply flowed out over the flat plain. Which may well have been liquid at some point. But this interface is not a shoreline.

Click to play embedded YouTube video.

I think it is generally a good idea to not treat anything we see on planetary bodies other than our own as "clear", "obvious", or any similar description. We simply don't have enough information about what kind of processes might be involved in surface building, we don't know all the materials present, we don't know the nature of the interior, we don't know the impact history. This is a good time to maintain a very open mind.

BRCM is pretty much Utopia except without sex, drugs and rock and roll. All which are curiously absent on Pluto too. Except "maybe" for some rolling rock?

Rolling Rock.jpg (12.06 KiB) Viewed 6963 times

Or a nitrogen-infused IPA.

Nitro IPA.jpg (7.29 KiB) Viewed 6963 times

Just keeping an open mind.

[GYATMnow]

No impacts craters on the plains while the mountains have a few, likely indicating the plains are newer than the mountains. Other than that, it's hard to speculate on the processes responsible.

[ta152h0]

this is a great ROI

[Sky Nerd]

The caption says the image is 30 km across. Is that the image featured on the Dec 14 page, or does 30 km across refer to the full size image after you click on it?

[Chris Peterson]

The caption says the image is 30 km across. Is that the image featured on the Dec 14 page, or does 30 km across refer to the full size image after you click on it?

The full strip (what you get when you click on the homepage image) is 80 km wide. So 30 km is a reasonable estimate for the width of just the cropped section.

[Guest]

The caption of the amazing picture says in part, "On the left is al-Idrisi Montes, mountainous highlands thought composed primarily of blocks of solid nitrogen." I also read (on Wikipedia) that only water-ice is solid enough at Pluto's temperatures to support mountains of such heights. So are the mountains which are higher than the al-Idrisi Montes made of water-ice, or is water-ice the base over which a coating of nitrogen ice is laid?

[JohnD]

To aid discussion, I'm trying to upload a copy of the wide pic from JPL with various features that I've circled.
But it appears that I can only link to a picture on the 'Net - I can't paste one here.
I'm sure I've done that before - have things changed?
Is there a way to paste a picture into a post?

Meanwhile, and in the absence of an annotated picture:
In the Planum, there are three dark marks ON what might be fractures. One has a a plume deposit to the right of it, so they all might be existing or past vents. One more mark is in the centre of a 'floe' between fractures (the one looking a tiny bit like North America, next to the 'shoreline')
Between the 'floes', along the fractures are what appear to be dunes, possibly condensed vent gases?

As we look to the left of the picture, behind the Montes, is an area of more finely broken terrain, some lesser montes and then an area that is less definable. There, I can see a large crater a the upper margin, three small craters in the middle and two larger craters at the lower margin. All are irregular and oval in outline, so they are most unlikely to be impact craters. Possibly vents, or 'pit craters' like sink holes, after material has vented leaving a void.

John

[bystander]

But it appears that I can only link to a picture on the 'Net - I can't paste one here.
I'm sure I've done that before - have things changed?

You can't link to images on your computer, unless you have a web page. You can, however, upload the image to The Asterisk. See the Attachments tab at bottom when posting.

[Cleofus]

I remember when there was all the rage about there being a "face" on Mars which is nothing more than the shadows of a mountain. Well in this picture, there are at least 5 Skulls visible and it simply makes the landscape more foreboding!