If "Pluto never comes within 11 AU of anything large", shouldn't that also apply to objects that are going to hit it?
(i.e. if things are spread so widely apart then the chances of anything hitting it should also be very very tiny too).

Here is a GIF of the original closeup image of Pluto and its deconvolved twin
There is a slight increase in resolution
Click to view attachment

I think they over-emphasised that a bit too much - I think it's very premature for them to claim that tidal heating isn't a major factor here when we know so little about the history and evolution of the Plutonian system (presumably they'll nail down the orbital eccentricity of Charon a bit more as a result of the flyby? Last I heard it was non-zero based on hubble measurements, which was a surprise)

The Eris flyby campaign starts here

Just think what those 30metre class telescopes under construction might do for discoveries in the outer Kuiper Belt (inner Oort cloud?)

OK seriously amazing stuff. The tiger stripe region of Enceladus looks very similar to the ropy potion of Charon's limb.
Also, is that limb-chasm on Charon going to displace Verona Rupes on Miranda as the greatest cliff in the solar system? (and greatest 22nd century low g freefall site?)

This is awesome x1000.

p

Wow...Shape from shaping I assume?

Pluto's mountains are interesting and to me they look vaguely similar to Callisto's ice spires. This is a Galileo image from orbit C30:

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There is one important difference though, the resolution of the Galileo image is more than 10 times higher than the resolution of the NH image. Callisto's spires are much smaller than Pluto's mountains.

On that particular mountain top I interpret those dark blobs as sublimation pits/sinkholes. There are obviously small amounts of more volatile components mixed in with the Water Ice. Quite a few of the Ice Mountains have these dark spots on various faces, not just on the tops. Its difficult to say if they are dark because of shadows or if there are also darker deposits left behind as sublimation residue or aeolian deposits. If this was Pluto Water Ice "bedrock" surely it would be almost pure, lighter volatiles having already risen to the surface.

Yes, but lines are often a further eroded stage (for mesas at least), and the bumpy stuff to the upper right of the arrowed mesa is typical of eroded mesa terrain. I think the black whale dusted region vs the white heart terrain transition is at play here - perhaps all the dark terrain is higher elevation capped terrain, and the heart is eroded - and this appears to be a transition zone. I think the biggest question of the mountains - where they pushed up or did the material around them erode/sublimate away? If it is due to erosion does it really take internal heat to do that over long time periods or are we just seeing a body sublimating away with dusty (maybe Charon dust) capped areas slowing down the erosion?

Pluto spends most of its time in a region of the solar system that would be quite similar, in terms of the number of potential impactors, to where Neptune and its moons are located. I would say that crater counts on the Neptunian moons (with the possible exception of Triton, since it was captured at some point and potentially altered during the capture process) should correlate with crater counts on Pluto/Charon.

In other words, if we see significantly fewer craters on Pluto/Charon than we do on Neptune's "natural" moons, then they are being resurfaced and are likely more active. If not, then the Pluto system is about the same age and/or has the same activity history as the Neptunian moons.

From what I was hearing today, the impression I get is that the science team feels strongly we're talking about the former, and not the latter, in their initial observations.

Since both Alan Stern and John Spencer post here frequently, I'd love to hear their takes on why they made the statements they made today. And, hey -- they have lots of time to post now, right? It's not like they're really, I dunno, busy or tired or anything right now...

-the other Doug

Trying to match the high-res image with the full disk view, I get this:

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I've always struggled to see any definite craters on Proteus or Larissa. I thought it was due to poor resolution, but I'm not so sure now. In any case, forthcoming data and study will help answer the question.

The canyon that we see on the edge of the righthand limb of the hi-res Charon image... where is that in the lower res image?

I'm looking at:


and comparing it with:


Are we looking straight down onto it in the low-res image? (i.e. it's in the middle of the disc?)

One thing that works for me with heavily compressed images is to add some noise.
That gets rid of the block artifacts and for some reason the entire image becomes more "readable".
Surely just a perception thing, but for me it helps.

Here's Charon "noised":

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The fact that all of Pluto's moons are in circular, prograde, coplanar orbits strongly implies that they are either primordial or of impact origin. That would seem to rule out even a three-body capture with an ejected interloper to explain Charon.

I think its south end begins closer to the left side of the disk (near a possible crater at ~9 o'clock not labeled in the low res image) and it runs toward the middle.

ETA: I believe this is it in the color image
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I think that one of the keys to understanding this terrain is understanding the physical properties of the various volatiles that dominate the surface and crust of Pluto. So:

Pluto Surface temperature range: 40-50K. Hopefully we'll get more detailed information on temperature distribution from the NH datasets.

We know that nitrogen will potentially liquefy at about 63K depending on pressure. This is more likely at depth where no boiling/ sublimation can occur. Sublimation will result in rapid heat loss and solidification on the surface.

Solid methane starts to get malleable and sticky at around 50K to 90K, so it may be largely responsible for a lot of the surface reworking, and it may be a seasonal effect.

There is also this paper on the rheology of solid nitrogen and methane:

link

Some other (rhetorical) questions arise with regard to the relative densities of the volatile components. How do they change within the temperature range found on the surface of Pluto?

The geology of Pluto is obviously pretty complex.

What are the possible stable mixtures? For example, are there methane hydrates/ clathrates.

It was interesting that Hydra is thought to be largely made of Water Ice. In my pre media briefing post I suggested the satellites might be bits of shrapnel from Charon's icy crust. We have seen at least two huge chunks missing from the surface, one at about 7 O'Clock from "Mordor" and another in the previous image below the Kms deep canyon, with possibly another below that.

It sounds crazy and probably is, but I'm liking this graze impact of Charon and Pluto. Charon does not have to have been travelling at Pluto's orbital speed if it had been ejected from inside the orbit of Uranus, it could conceivably have had a closing velocity such that a brief kiss on Pluto's cheek was enough to enable it's capture. I wonder if there are ballistic's gurus who could figure that out from the scars left behind?

Remember the solar system objects we see today are the amazingly flukey, improbable results of a 4.5 Billion year old shooting gallery. Wild, near catastrophic collisions have been avoided by the Earth and Uranus. Why should a mere close shave be any less likely. Charon was moving from below the plane of the ecliptic and the impact could well account for Pluto's now unusual inclined orbit. An orbit that would remove it from the concentrated fire zone of the ecliptic when supposedly objects were being ejected at a rapid rate from the inner solar system by Jupiter and Saturn. That piece of luck is possibly why the Pluto system survived.

They used to use "blue noise" when printing images on dot matrix printers to make the images more realistic. The correct noise addition can make a huge difference in how it looks visually.

You are talking about an extremely improbable sequence of events, Sherbert, esp. so given the very small size of objects in the Pluto system.

Not impossible, of course, but vanishingly unlikely, even more so given the remarkably symmetric, orderly orbital state of the system.

My thoughts are that it also coincides with the area of highest levels of insolation. The pole is constantly exposed to the sun. Maybe there is a connection there? Higher ablation/sublimation rates perhaps?

This is a sequence of Charon images, some of them borrowed from earlier posts here, to try to follow the big rifts around the surface.

Phil

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The best reference is the "Mordor" dark patch. In the high-res image the open square end of the depression points to about 4 O'Clock, in the low-res image it points to about half past nine. So it is about halfway between the western rim and the centre line of the hemisphere. The flat lighting makes it difficult to see. It does mean the huge crater/volcano in the centre of the low-res image is not visible in the latest image, though the rugged terrain on the eastern rim of that image suggests these are the foothills of that feature. The large cluster of what could be secondary craters here suggests it is an impact crater, though volcanic ejecta could cause secondary cratering also.

And an attempt to match features. It is possible that the upper left valley on the limb in the latest image is feature F in the earliest view, but I'm not certain yet. To try to help track it, look at the bright spot inside the dark area... at left in the best image, at right in the lowest resolution image.

Phil

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Some possible matches between the color image and the latest

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I know, its seems like a very long list of maybes, but the system only survived because it beat the odds for its destruction. Something very particular ensured it's survival.

Just a thought, but I can't help think in terms of the Antarctic dry valleys as a kind of water ice sublimation analogy. So will areas of higher ablation have a darker colour due to a gradual concentration of non volatiles?

If we think about the sublimation process, maybe some tholin powder is being continually (seasonally/diurnally) entrained into the released gas, but the volatiles emission will be the dominant process. The resultant nitrogen snow will fall in areas of predominant deposition which may be lighter in colour.

Neptune migrating outward captures objects in its resonances like Pluto and many other objects. Neptune encountering another planet causes its semi-major axis to jump would also result in the capture of objects in its resonances. Objects having close encounters with Neptune have their orbits altered (which can increase their eccentricity of inclination) but rarely enough to eject them in one encounter. Nearly 25 years ago someone claimed that the solar system once had a thousand Pluto-sized objects most of which were lost leaving Pluto and Triton as the remnants of the population.

Feature A should be present in the 3rd image as well. It would be helpful to mark the relative axis running from the end of the rift (H) through the loops below the dark splotch. It looks like it rotates clockwise about 120 degrees (through the 5 image sereis)?

back from dinner


yep , but that one was a very quick one i used a hipass first and only ONE solar angle
the mountains on the right are TOO HIGH


i am about to put together a 3 angle image so they should be a bit better
-- for 15 min from garbing the image to posting the few shots

Yes.

And add into this mix lithologies composed of usual silicates, et al, with the addition of the unusual mineral oxidane, which will prove to have unusual properties under the cryogenic conditions on Pluto, especially in the presence of the typical suite of gas giant gases under cryogenic conditions.

This is a wonderfully strange little world.

--Bill

True, but I'm merely questioning your assertion that the darker "mesa material" has to be much harder. If it was much harder, there would be mountains around that had eroded off into points or ridges - but I would think they would be far fewer as once the mesa is gone, erosion would accelerate. The but the very low number of "mesa mountains" in this image seems to imply (to me) that that top material is NOT much harder - if at all.

Otherwise I agree.

Hydra - I subsampled the released Lego Hydra back to its constituent pixel scale, and enlarged again in stages with a bit of judicious stretching where needed.

Phil

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Perhaps not dunes, but a continuation of the striations (associated with venting ala Enceladus?) partially buried in whatever deposition material makes up the flat terrain.

Of significance is that Pluto and Charon are mutually tidal locked. Conservation of angular momentum means that initially the two bodies were once much closer and there would have been quite significant tidal heating. Given that the orbits of Charon and the smaller moons are all in the same plane your suggestion of impact rather than capture would seem most logical.

Charon reminds me of earth's moon!

Someone correct me if I'm wrong, but if Charon has a canyon 6-10km deep (as has been reported), that would make it one of the deepest canyons in the entire solar system -- in the same league as Earth's Mid-Atlantic ridge and Mars's Vallis Marineris. Considering the size of Charon, being in that company is even more stunning.

I'm going by this wikipedia page: https://en.wikipedia.org/wiki/List_of_large...he_Solar_System

Is this accurate though? I thought Miranda had canyons as deep as 20 km...

I totally agree. We have a lot to learn about phase transitions of water ice mixtures,

It's interesting to regard water as a mineral series, the most extreme of which is metallic ice as found in the gas giants, but that's for another thread.

Ok, so this is really stretching it but I though I'd have a go at running Hydra through my Process 2 experiment.

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I'll be incredibly shocked if any of this comes out in the final images but that's why this is just an imaging experiment.

I agree that classical erosion may not be a dominant factor, or if it is, we need to be clear on the proposed mechanism.

From a sublimation point of view, the presence of contaminants that reduce the vapour pressure of any particular layer would increase the "hardness" or resilience to "erosion". We might have to rethink the term "hardness" in that context.

"I thought Miranda had canyons as deep as 20 km..."


A lot of nonsense is talked about the topography of Miranda. We don't have great stereo for it, and many people misinterpret the geometry of the giant scarp Verona Rupes (which is a talus slope at the angle of repose, not a vertical cliff).

I would expect that Miranda's rift valleys are on the same scale as these on Charon.

Phil

I think you are probably right. My knowledge in geology is far to be as outstanding as most people here, but I agree with many others (including you) there's strong evidence for a large deposit in that area that submerged some ice mountains. Enceladus comparison is interesting but there's important discrepancies and Pluto's striations are relatively small.

The ondulating features look like dunes from afar but upon closer examination, I seriously doubt they are. If they were, they would cover the entire plain, not only the contour. Also, they are quite broken, not perfectly continuous, as if an erosion process was stripping layers of material depending the local topography, terrain composition and what I would call "local conditions". It seems like some top layer deposits were eroded, giving the plain a "step-like" appearance where the "rockbed" is nearer the surface thus more prone to erosion.

I tried to compare these "dunes" with some terrestrial deserts like Gobi and Taklamakan that feature that kind of ondulating broken "dunes". The comparison is far-stretched and stops there as I'm comparing unrelated geological features. But my question is this one, if it ain't caused by wind, could sublimation and thawing make such erosion patterns? Or simply deposition?

If Pluto's atmosphere was not so tenous, comparison with Titan dark terrain dunes could be interesting. But Titan dunes have nothing in common with what we see except they are found where there's dark "powdery" material. A coincidence? I'm really curious to see what NH will tell us about the atmosphere and what kind of weather can be expected.

If I had to sum up my actual hypothesis, I'd say the deposit is layered and exposed to a unknown erosion process. There was a discussion about mesas. Maybe the ondulating features are somewhat related to this... and the only flat-topped mountain seems to be bordering the deposit. All other mountains seems to be well defined which makes me think they aren't subject to the kind of same erosion. All that rambling will probably outdated as soon as a better resolution picture is available. And to be honest, it could be simply a result of deposition patterns (layering) according to said topography and local conditions without no need for harsh erosion. It would explain with mountains are embedded in the deposit but looks quite pristine otherwise.

The good thing is that we should have a better understanding soon since the other hi-resolution pictures will cover that neighboring areas. An interesting thing about Pluto mission is that it forces one to go back having a look at others moons and planets. No wonder NH team were so excited during today's press conference.

EDIT: Aldebaran's got a point about sublimation and changes over time in material composition affecting "hardness", features, erosion patterns and deposits. For those familiar with Earth winter, we have all observed how snow and ice behaviors and characteristics are greatly affected as the "contaminant" ratio raises. Sure sublimation is another beast, but it means Pluto's element concentrations are bound to vary and affect local and global geology over time which could drive erosion patterns that are quite unrelated to "weather", fluids and other classical things. What we have is deposition, sublimation, all driven to some point by solar radiation varying greatly according to a highly elongated orbit. To that, we add internal geological processes and we get quite many elements to shape a planet with rich and varied landscapes. As Earth and Titan have cycles based on fluids, winds, thawing and other patterns thanks to their rich atmosphere, it seems weather cycles based on sublimation on icy planets with tenous atmosphere can be powerful tools to shape features. NH other instrument measures will really be useful to see how things pieces together. Just guessing about landform... remains guessing!

Matt

a few new images in 3d
-- i removed the minor planets surface curve
45 Degree rotation on each image





-- google photo album
https://goo.gl/photos/PYtRkwSK4EvQLyuD8

a few close up's

Outstanding work again, John! Really makes me appreciate the jagged relief of this landscape.

Also made me recall that the troposphere is thought to be only 1-2 km above the surface mean. Many of not most of these areas seem to be well above that. Perhaps there are discernible differences in surface appearance on features that pass through that boundary, possibly due to differences in exposure to ionized atmospheric constituents (predominately nitrogen species)?

Pure speculation, of course.

for those looking at the Hydra image from 13'th 23:14
page 12 of "NH_Obs_Playbook_LORRI-MVIC.pdf"
http://pluto.jhuapl.edu/Multimedia/Science...amp;search_cat=

this is a pointer to the Sun and the terminator

a guess on the rotation

so that 14 px image is in about 45% of sun

Wonderful work John! Thanks for sharing.

A collision between an impactor and Pluto requires that two things be in the same place at the same time. A capture scenario would require that three things be in the same place at the same time. To a decent approximation, the probability of the latter would be the square of the probability of the former. Not very likely.

I thought Emily said that the phase angle on the Hydra image was only 16 degrees .... ?

Phase angle of Hydra is ~21.5° according to Observation Playbook.



Fantastic work John!

My attempt to process Hydra (updated). Applied the same processing technique as in this post.

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Amazing work John! Those visualizations really make the image so much more readable... and in such short-order too