A major seismic event happened across the entire globe of the Earth today.

"This event is what we would expect to see if millions of swear jars suddenly burst, all across the civilized world," a noted seismologist stated.

-the other Doug

John Spencer -- "You do not need tidal heating to power ongoing activity in an icy body."

-the other Doug

Charon has been active!

-the other Doug

It has been since before the 6/30 safing event that we've had any image releases. Now they're changing orbits, but either 1) haven't gotten the cameras working again, or 2) haven't seen fit to release any images taken since the safing event?

Something seems wrong, there. The Dawn team has not been very reticent about releasing images, and I'd think if they had begun taking pictures again, we'd have seen at least one of them.

I wonder if there is something more seriously wrong with Dawn than we've been told?

-the other Doug

Interesting -- I saw an update on the NASA TV landing page a couple of hours ago saying it was changing to 01:30 UTC. Well, we'll see what happens, unsure what they're going to say with another more than an hour before we hear if NH phoned home.

-the other Doug

I believe the NASA TV program has been shifted back an hour, so won't be starting for more than an hour. The description of the program was also changed, from some general description to saying it would specifically be a press conference.

-the other Doug

Fascinating!

The main part of the Heart looks for all the world like Greenland, with some "ground" exposed along its northern extent and glaciers covering the remainder. The whole thing looks a lot like a remnant icecap. There is definitely vertical relief to this feature. It also appears that the large, darker features to the left of the Heart (that include the head of the Whale) also form a plateau-like relief feature, in many ways reminiscent of a dark-toned remnant icecap. Maybe a lot of places on Pluto develop icecaps as time goes on, and some of them take longer to lose the deposited ices than others?

Also, throughout the northern plains, I'm seeing large-scale light-toned streaking that looks a lot like the wind streaks I was predicting in my WAG post. I also see one small, suspiciously dark streak-like feature that could be something like the black nitrogen geysers seen on Triton. If so, it's the only suggestion of one of those that I see in the entire image.

I think it will be extremely illustrative to see the surficial details of the "icecap" in the main body of the Heart, since it will likely show details of both ice/frost deposition and erosion. At this resolution it also appears to exhibit streaking or grooving, consistent with the winds that would blow from the most-highly-insolated north polar region towards the shadowed pole. I bet we see indications of different prevailing wind patterns, too, since these will change as Pluto's orientation to the Sun changes.

It'll be interesting to correlate the predominant deposition/erosion patterns to the Pluto system's orientation to the Sun over time, and to its distance from the Sun. I'm certain that, like Earth, one polar hemisphere gets higher insolation than the other due to correlations between aposol/perisol and seasonal tilt.

-the other Doug

Looks like Curiosity blew through a brick wall! Replete with pieces of similar-sized, rectangular-prism-shaped rocks that are red on the outside and the color of concrete on the inside. Plus little pieces of white mortar lying around!

I think our little rover don't know her own strength!



Seriously, it is interesting to see so many rock pieces that have such nice, clean, square corners and right angles. It really does give the look of a demolished brick wall.

-the other Doug

I agree with belleraphon above, the polar region is beginning to look a lot like Triton's cantaloupe terrain, and I'm pretty sure I see a few impact caters in it. Also, a lot of the surface may show degraded and altered craters that don't appear very round from this distance.

But I also agree with belleraphon, too, in that I'm almost totally overwhelmed by this new image. I feel like a kid on Christmas Eve -- I can't wait for next week so we can start opening our presents! (And the nice thing is, we will keep getting presents to open for the next several months as the data slowly comes back down.)

-the other Doug

Since this is really getting to be the Very Last Chance, here are my bold predictions as to what these tantalizing features will resolve into:

- The dark streak along one side of the major light-colored, straight-edged terrain unit will be shown to have been deposited by a mega-version of the little nitrogen geysers seen on Triton. It will have started at the poleward end with a big geyser, and entrained dark material was emplaced downwind of that geyser, towards the equator/terminator.

- The "whale" will end up apparently having been wind-emplaced, with large amounts of dark material being ejected from the right-most of the big dark circles that lead up to the whale and emplaced by winds blowing more along the equator, actually trending up towards the pole. This will have to have happened when Pluto wasn't pointing one rotational pole or another at the Sun, since the wind pattern (from pole to equator) we would see now would never blow in that direction.

- Many of the dark areas will be different in composition from one another.

- We will see obvious signs of what will look like wind erosion on a massive scale, resulting from gasses being released from a polar hemisphere as it turns sunward and accumulating on the now-dark pole. The biggest and most obvious wind features we will see will seem to stream back from the pole down to the equator, but we will see other patterns from other epochs. We will also see evidence of repeated deposition and re-sublimation of ices, rather like what we see at the Martian poles.

That's really all I want to predict. Let's see if I'm right or if I'm completely and totally wrong! (And if I'm wrong, I'm going to be even more delighted to see what it all actually looks like...)

-the other Doug

Trying to get my head around how to pronounce the Spot 5 crater, I googled the name. Lots and lots of results identifying Occator as the God of the Harrow (or hoeing, in modern parlance), whose spirit was invoked by priests of Ceres, but very little with useful pronunciation guides.

What little I found suggests it is pronounced ah-CATE-ore. Not OCK-a-tore.

I will say that, in the rotation animations, you do consistently see what appears to be a specular reflection moving along around the pole. Its shape changes around its edges, but it stays pretty consistently centered around what would appear to be the sub-solar point. It also doesn't revolve as the planet rotates -- even as its edges change shape, when a bright area moves outside of the specular angle, it becomes darker again and seems to blend in with the surrounding dark polar terrain, while the terrain moving through the specular angle behind it brightens.

Since the bright area changes its edge shape as the planet revolves, it seems to me we could be seeing bright elements of the landscape moving through the specular angle, and as they move away from the specular angle, that landscape darkens again (in current resolution) to the average, darker appearance that the entire polar region features. The distribution of these specularly-bright features varies throughout the polar region, so as the planet turns, we see the outlines of the region that is full of these small, bright features. That outline changes as the planet rotates.

I envision a lot of relatively small craters, for example, all with frosted ice-covered rims, but which have floors and inter-crater terrain of a darker albedo. As the specular angle changes, the crater rims reflect sunlight back to LORRI, and as they rotate away, the overall albedo of that region fades down to what we see from the rest of the polar region.

Of course, it could be other small features that reflect light in a specular fashion embedded in the darker terrain, but my bet would be on crater rims. Hopefully, we'll know a lot more soon.

-the other Doug

It has also been mentioned here, in a number of different contexts regarding ESA mission scientists and their contributions to the PSA, that they are not always made in a timely manner.

AIUI, there is little in the way of enforcement of the submission deadlines, and from observation, they seem to be recognized more in the breach than in reality.

In other words, while the data should get there eventually, don't get too upset if they aren't submitted to the PSA right on schedule, there is precedent for such submissions to run significantly later than the scheduled dates. And that's about all I can really say, here. Though I'd love to hear from Emily her feel for the timing. She talks to those people one heck of a lot more often than I do...

-the other Doug

Looking at the base of the mountain, it looks like the surrounding terrain embays the base of the mountain. In other words, the mountain was there first, and the surrounding surface was emplaced later, covering a lower base this mountain had before the resurfacing events that happened around it.

Most interesting is the crater directly next to the flat side of the mountain (on the left side of ZLD's image above). The little spit of surface between that crater and the mountain is also embayed against the mountain, but shows no signs of piling up material against the mountain. On the other hand, that side of the mountain is flattened. I suspect that the eject from that crater's impact blasted off some of the side of the mountain, and the resulting settling-out left the embayment looking like it does on the other sides of the mountain.

-the other Doug

These images of Pluto are beginning to remind me of the far-encounter images of Mars from Mariners 6 and 7. Getting clues about the albedo patterns, but still not close enough to characterize the surface in either a local or a global view.

With New Horizons, though, we'll be getting more than just the two small areas of Mars that those 1969 flybys gave us in much higher resolutions, which will make a great deal of difference.

I am really, really getting antsy for the incredible images that will start to come down over the next few weeks. It's a little like how I felt in late June of 1969, having graphed and plotted every scheduled event of the upcoming Apollo 11 mission and left to just wait for it to start. It's hard to wait to see something you've been looking forward to seeing most of your life...

-the other Doug

Ooops, sorry. I see that I mis-spoke a bit. I didn't mean to say we were seeing active fountains, I meant we may be seeing the results of fountain-like activity in the past having emplaced very high-albedo material at S5, and very low albedo material in other places, like the "scratches" type formation that has been noted to be surrounded by dark terrain.

I was referring to the end effect of such fountain activity, not trying to say it's happening right now. Sort of hard to say how long ago something like that might have happened, though. It will help enormously when we start getting some compositional clues.

-the other Doug

If you're right, Habukaz, then this makes two different sets of features that resemble cryovolcanic versions of fire fountains. At region 5, here, very bright effluent has been emplaced, while in other areas, near the scratch-like wrinkle features, dark material seems to have been emplaced.

I wonder if the same processes are generating both types of features, the difference being the specific type of "lava" being generated. I know that, on the Moon, differences in the lavas feeding the various fire fountains generated glasses ranging in color from green to red to black -- could different cryo-lava constituents determine whether you get a high-albedo unit emplaced vs. a low-albedo unit?

-the other Doug

Excellent point about tidal heating, JRehling. It would seem to me, though, that most of the tidal heating would occur while the two bodies were going through the process of tidally locking to one another. Once the librations have settled down, you'd have far less pull happening inside the two bodies, seeing as the rotations of each have now been damped into the synchronous lock. You'd expect the most heating to happen while the rotation rates were slowing down to complete the locking process.

With the far greater distance between small bodies once you get out as far as the Kuiper belt, accretion via gravitational attraction and random collisions is a far slower process for bodies as far out as Pluto. Since the smaller moons are still tumbling chaotically, I imagine there's at least a chance (if not a high-level probability) that Pluto and Charon came to be tidally locked relatively recently, at least as far as geological time goes.

If so, the heating may have happened relatively recently, and the bodies may still be in the process of cooling down. Now, that would make a most interesting set of observations.

-the other Doug

I imagine that impacts onto an ice world (or an icy-rocky-slush world) generate internal heating from acoustic/seismic energy propagating through the body. As we can see, there have been a lot of large impacts on Ceres. so there has been at least localized heating capable of melting ice, at least for a time. I'm not saying that a peppering of impacts could keep the core continuously warm -- I'm just saying that, when it gets really whacked and a big crater or basin is formed, I bet that anything from very localized to larger-area heating occurs. Chaos being what it is, I can imagine pockets of water melting out inside the crust from such large impacts, refreezing, and then getting exhumed by later impact and tectonic forces.

This could mean that Ceres may have been dead, for all intents and purposes, for billions of years, but that a good, solid whack could make it wheeze and burp a bit, even now.

I think when we get a better feel for the compositions of the various texture/albedo/color units, it will tell us a lot more about the possible histories of this curious little world.

-the other Doug

Oh, I agree, Phil -- with one important codicil.

In this solar system (and, I suspect, throughout this Universe), most of the circular features seen on a solid body are somehow the result of impact, or their shapes have been controlled -- as with many of the generally circular lunar maria -- by impact. The lunar maria I mention are not in and of themselves impact features, but a majority of them fill impact basins and thus their overall shapes are defined by impact processes. I would go so far as to say that impacts form almost all of the circular features on solid bodies without atmospheres, and a vast majority of them on planets with thin atmospheres. (Yes, I know that Io is something of an exception, but then again, Io doesn't retain impact features for more than a second or two, geologically speaking, and there are few if any other bodies in the solar system with that particular characteristic.)

When I see what appear to be circular features on a solid body with a thin to non-existent atmosphere, I'm generally going to assume impact processes are responsible for the circularities, until I see evidence otherwise.

We are seeing, even at this resolution, some circular-looking albedo features on both Pluto and Charon. (And, of course, many non-circular features, as well.) In point of fact, the circular-looking features in the degraded image of the Moon you put together (excellent work, BTW) are in fact features whose shapes are defined by impacts.

Again, I agree that we can't say anything definite yet about the topography on either of the bodies that are just now coming into useful resolution through New Horizons' cameras. But when I see something that is resolving out as a circular feature, I'm going to begin to strongly suspect that it's an impact feature.

This way, anything circular that ends up not being an impact feature becomes an incredibly delightful surprise...

-the other Doug

The explanation I have read is that localized magnetic fields redirect some of the incoming solar wind charged particles, "shadowing" the areas in the swirls from solar wind bombardment. The idea is that the solar wind darkens the regolith over time, and the shadowing effect reduces the solar wind flux along the magnetic field lines. Since the swirls can be thought of as a 2D representation of the 3D field lines above these areas of localized magnetic fields (just as a shadow of a 3D object on the floor is a 2D representation of the object casting the shadow), you get swirling patterns of regolith that has not been darkened by the solar wind flux, and thus appear lighter.

There may be other magnetic effects, including electromagnetic lifting and depositing of dust, with the localized magnetic fields affecting the pattern of deposition. I've seen papers about this "levitation" of lunar dust along the dawn terminator (possibly observed by both ALSEP dust detectors and by one of the Surveyors), and I read one theory (sorry, can't remember where) that the magnetic anomalies disrupt that process and cause suspended dust to fall abruptly, or at least be transported along the field lines. That could also explain how the brighter regolith is "freshened" over time.

Again, I think these theories (especially the first one) are somewhat well-accepted. I'd believe them more than the Brown University study.

Yeah -- I just can't see comets producing the extremely large extent of the swirls as observed. The brightening effects of gas flow over the surface would be darkened over the course of time, such that if the swirls were from such gas transport, we would see them for a relatively short time. Since gas transport just "freshens up" the regolith, the constant rain of small to tiny impactors will darken that kind of thing in timescales far, far shorter than the darkening of rays from impacts.

Also, over a long period of time, you'd expect cometary impacts all over the lunar surface, and in fact they'd have to have happened all over the Moon's globe. We're supposed to believe that they only happened around Reiner Gamma and the few other places we actually see them? I also strongly question that gas transport brightening of the soils would last even a hundred thousand years, much less the 100 million years noted in the article.

Finally, the swirls do seem to be associated with magnetic anomalies. Why would gas transport cause magnetic anomalies? And only in the limited areas where we see the swirls?

I just don't think the comet impact theory works.

-the other Doug

Agreed, Nick -- but in terms of speculating based on the best available images, I have to say that the first three of that four-image set are extremely suggestive of a basin. Especially (in my re-posting of just the first three images, below) the middle and right images. The left image shows an entire circular feature that could be just an albedo feature, but the second shows it on the terminator, partially shadowed, with what appears to be a far rim in sunlight. That suggests the far edge of the circular feature is raised above the center of the feature. The right image shows a similar lighting of the far rim, but Pluto's aspect to the sun has changed somewhat and the portion of the far rim illuminated is slightly different.

Again, yes, I could be reading too much into images of still-poor resolution. But on most (if not all) bodies in this solar system, a circular feature this large in comparison to the size of the body is an impact feature. I guess I'd say I would be very, very surprised if this isn't a basin. I'd even place a bet on it, if I had any money to bet with...

-the other Doug

I'm agreeing a lot with John's points above. Especially where he notes that the darkest albedo unit seems to overlay the area around the cracks on the right of the image. This looks like a classic example of fissure volcanism, where the Cerean equivalent of fire fountains sprayed from the fissures, emplacing the Cerean equivalent of pyroclastic material over the surrounding terrain. Compare this to the black/orange/red/brown volcanic glasses on the Moon that were emplaced by ancient fire fountains. (Look up the orange/red soil and dark mantling found at Apollo's Taurus-Littrow landing site for good examples.)

The thing I wonder about is how ancient are the landforms we're seeing? Except for impact alteration, any volcanism (even cryovolcanism) on Ceres driven by internal heat would have to have shut down gigayears ago. I wonder if Ceres would have looked pretty much exactly as it looks now three billion years ago?

-the other Doug

The circular dark area near the bottom of the disk in the best-processed of the recent images looks like a huge basin to me. One that either has a very dark floor, or that is in shadow as it rides the terminator 'round and 'round like a carousel. If so, the sun shining on its ramparts may be what has made Pluto look really lumpy in the early approach images.