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

[Alohascope]

Wave action though is caused by the interaction between the gravity of the Sun and Moon, by the constantly changing location of the Moon over the Earth's surface and by wind action on the water surface. Pluto has no appreciable atmosphere and no surface liquid (at least given it's current orbital location) so mechanism 3, surface wind, won't cause wave action. Charon and Pluto always present the same face to each other. If you stood on Pluto and looked up at Charon, it would never change it's location in the sky. So the area of greatest tidal influence never changes on Pluto. This negates the second mechanism for the creation of wave action. As to the first, the relative effect of gravitational interactions between the Sun and Charon on potential liquids on Pluto. This works well on Earth because the moon orbits earth on a relatively similar plane to Earth's solar orbital plane. Currently the Pluto/Caron orbital plane is rotated almost 90deg from the solar orbital plane and alters the tidal dynamic. Though in about 60 years or so Pluto/Charon will return to a similar orbital dynamic to that of Earth & Luna.

Tides and wave action would be an extremely difficult, short lived, and unlikely source of energy on Pluto

Just as an interesting observation .. Pluto does have winds .. that is evident from the snow drifts .. of course that would have no effect on the ocean beneath the shell.

[ALohascope]

So is water on earth insignificant, I think the question is anwsered very well in this excert.

Scientists calculate that the total mass of the oceans on Earth is 1.35 x 1018 metric tonnes, which is 1/4400 the total mass of the Earth. In other words, while the oceans cover 71% of the Earth’s surface, they only account for 0.02% of our planet’s total mass.
The link, full article
http://www.universetoday.com/65588/what ... -is-water/

I am an accountant by trade and i am fairly certain .02% of any of my numbers is ignorable, in fact i could lose that at stock take and no one would notice.

however i do except that 135000000000000000000 tonnes is a big numer and one hell of a swimming pool.

Surface oceans are the tip of the iceberg. The most recent discovered source url'd in my post is three times that volume, and that is only 400 miles beneath the surface. The subsurface Amazon is hundreds of miles wide and as long as the Amazon. We have just begun to 'discover' water IN our planet.

[Alohascope]

Ah .. here's one .. please excuse the advertisement .. the animation is worth the wait. It not only shows how rough the gravitational 'tides' are, but shows how Pluto's own motion is very rough, seemingly rough enough to rough up its ocean.

http://www.space.com/31071-plutos-moons ... izons.html

Not sure what you're taking from that. Pluto's outer moons have almost no tidal effect on Pluto or Charon.

"Almost" is the key word here, Chris. How much "almost" does it take to set up tides in Pluto's ocean? On earth the highest tide is not the 16.3 meter Bay of Fundy tide but the Burntcoat tide in Canada's Arctic of 17 meters .. 55 feet is not insignificant, and earth has one moon while Pluto has five .. five moons plus Pluto orbiting in a way destribed as "pandemonium" by some scientists. Pandemonium creates stress, does it not?

Also, if you watched the animation, Chris, you would see Pluto circling its system's centre of gravity very tightly, though not, it appears, in a circle, but in a slight elipse .. when those factors are combined with your "Almost" no effect of the outer moons on the oceans I will easily say there is a significant sloshing around of the ocean caused by gravitational disturbances.

You might like to view and read these urls which deal partly with oceanic sloshing affected by gravity.

http://www.space.com/31385-saturn-moon- ... steam.html
http://www.dailymail.co.uk/sciencetech/ ... t-ice.html

[Chris Peterson]

Not sure what you're taking from that. Pluto's outer moons have almost no tidal effect on Pluto or Charon.

"Almost" is the key word here, Chris. How much "almost" does it take to set up tides in Pluto's ocean? On earth the highest tide is not the 16.3 meter Bay of Fundy tide but the Burntcoat tide in Canada's Arctic of 17 meters .. 55 feet is not insignificant, and earth has one moon while Pluto has five .. five moons plus Pluto orbiting in a way destribed as "pandemonium" by some scientists. Pandemonium creates stress, does it not?

No, pandemonium does not create stress. The orbital and rotational dynamics of the system are complex. That does not mean the tidal forces are. Consider the tidal force of Nix on Pluto. It is about 9e11 N. For reference, that's 10 million times smaller than the tidal force of the Moon on Earth. Scale that to Pluto and the tidal force of Nix is enough to raise a tide one or two micrometers high given complex underwater topography, or a fraction of a micrometer given a smooth ocean floor.

[Alohascope]

Not sure what you're taking from that. Pluto's outer moons have almost no tidal effect on Pluto or Charon.

"Almost" is the key word here, Chris. How much "almost" does it take to set up tides in Pluto's ocean? On earth the highest tide is not the 16.3 meter Bay of Fundy tide but the Burntcoat tide in Canada's Arctic of 17 meters .. 55 feet is not insignificant, and earth has one moon while Pluto has five .. five moons plus Pluto orbiting in a way destribed as "pandemonium" by some scientists. Pandemonium creates stress, does it not?

No, pandemonium does not create stress. The orbital and rotational dynamics of the system are complex. That does not mean the tidal forces are. Consider the tidal force of Nix on Pluto. It is about 9e11 N. For reference, that's 10 million times smaller than the tidal force of the Moon on Earth. Scale that to Pluto and the tidal force of Nix is enough to raise a tide one or two micrometers high given complex underwater topography, or a fraction of a micrometer given a smooth ocean floor.

http://www.space.com/31071-plutos-moons ... izons.html .. a good simulation. I can't believe the pandemonium of those moons plus the tight motion of Pluto orbiting the system's center of gravity does not create enough stress to create waves. However, moving on:

Another potential source of the ocean's waves: http://www.abc.net.au/news/2015-11-16/i ... lt/6938648
If there are sub-surface ice volcanoes erupting, as sub surface volcanoes erupt on earth, they would probably create waves.

But here's a new thought .. it seems even the system's center of gravity shifts, which is not surprising given the pandemonium. http://www.techtimes.com/articles/10520 ... -moons.htm

To my eyes .. Pluto's bucking about would cause significant tidal sloshing, currents, waves.

[ALohascope]

Then again: when you watch that animation of the system long enough you see the moons lining up on one side of Pluto or the other .. that would create a lot more pull than Nix alone.

http://www.techtimes.com/articles/10520 ... -moons.htm

A suggestion: editing capability for guests .. I'd have to make fewer posts. Or maybe I just can't see the 'edit' button.

[BMAONE23]

Then again: when you watch that animation of the system long enough you see the moons lining up on one side of Pluto or the other .. that would create a lot more pull than Nix alone.

http://www.techtimes.com/articles/10520 ... -moons.htm

A suggestion: editing capability for guests .. I'd have to make fewer posts. Or maybe I just can't see the 'edit' button.

A better suggestion...register and stop being just a guest

[Chris Peterson]

Then again: when you watch that animation of the system long enough you see the moons lining up on one side of Pluto or the other .. that would create a lot more pull than Nix alone.

No. The animation is telling us nothing about tides. Tidally, the Pluto system is basically two bodies: Pluto and Charon. There is a very strong tidal force between the two, but since they're tidally locked in a low eccentricity orbit around each other, that tide doesn't do much work. Nix and Hydra are the only other two bodies that could produce a barely detectable tide, but that tidal force is extremely small- not enough to distort Pluto or Charon to any degree, not enough to move material, even liquid if it exists. Styx and Kerberos would have no tidal effect at all.

You see patterns in the orbits because of the complex resonances that exist. Even a perfect syzygy condition, however, would not produce any significant tidal forces. Whatever is going on with Pluto's geology, tides are almost certainly not a factor.

[geckzilla]

A suggestion: editing capability for guests .. I'd have to make fewer posts. Or maybe I just can't see the 'edit' button.

This will never happen. Guest accounts are limited due to the ridiculous ways people use them to abuse the forum.

[Ann]

Alohascope, excuse me, but what are you up to really? You are posting like crazy here, and you have made more than one crazy claim, too. For example, you said that the Earth is not a rocky planet. The slightest googling effort would have told you otherwise.

Wikipedia wrote:

A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
...
Terrestrial planets have a solid planetary surface, making them substantially different from the larger giant planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.

Click to view full size image

Here is a picture of the structure of the Earth. The picture was made at the University of Leeds.

Further googling will get you to one hit after another about Earth as a rocky or terrestrial planet.

So once again, Alohascope, what are you up to? You make no attempt whatsoever to really try to find out if your hypotheses are correct. You listen to no one. People can throw a ton of evidence at you, and you just shrug it off. In my opinion you are not interested in the universe or the solar system at all, just in your own fantasies about them. That sounds harsh, but I'm afraid I mean it. Perhaps you will change in the future, so that you become a valuable member of these boards. But for now, I don't think you belong here.

Ann

[sallyseaver]

Seeing all the tolerance and dialog so far, is it okay if I jump in? I'd like to propose my ideas about Pluto: From Mountains to Plains. I just hope you have some left-over patience for me.

I am not alone in thinking that the Sputnik Planum could be an artifact of a glancing blow (or impact).

My favorite theory of solar-system formation [Mass Vortex Theory] includes a Killer Crash between a recently formed planet Illo and newly-forming planet Smithereens [Smithereens becoming the Asteroid Belt]. (The Crash occurred in the radial distance between Mars and Jupiter.) I believe that Illo made a glancing blow to one of its moons (Pluto) and deposited some debris during this event. Look at the margins of the reddish mountainous stuff at the edges of the off-white polygonal shapes in the Sputnik Planum in this Dec 14 image. It does not appear to penetrate the ice, but rather sit on top of it.

The impact of the Crash caused Pluto and Charon to be thrown away from the Crash site, where they ended up in the Kuiper Belt. This explains why Pluto is spherical like a planet or a moon, but does not orbit the Sun in the ecliptic.

Also, Illo had a lot of sulfur, the red allotrope S3 as well as yellow allotropes. I believe the red allotrope of Illo shows up in material mixed with the ice mountains of Pluto to the left of Sputnik Planum. Also Pluto has a dusting of light yellow sulfur from Illo in the north polar region.

I am familiar with the idea being put forward by scientists analyzing the New Horizons data that the red stuff on Pluto is from tholins --- tholins that are formed high in the atmosphere from radiation. But if that is where the red material comes from, then why wouldn't the red stuff be distributed over the whole planet instead of in a specific region?

The geometric shapes on the ice in Sputnik Planum are indicative of the ice being partially broken and then refreezing. Pictures:
---https://www.flickr.com/photos/gdanmitch ... H5-hEogws/
---http://www.latimes.com/science/la-la-na ... photo.html
---https://www.flickr.com/photos/mr_fabulous/5455430949

Sputnik Planum sort of looks slightly indented in this image
https://en.wikipedia.org/wiki/Sputnik_P ... 150917.jpg
(but I know not to make a lot of it since appearances can be deceiving).

[Alohascope]

Alohascope, excuse me, but what are you up to really? You are posting like crazy here, and you have made more than one crazy claim, too. For example, you said that the Earth is not a rocky planet. The slightest googling effort would have told you otherwise.

Wikipedia wrote:

A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
...
Terrestrial planets have a solid planetary surface, making them substantially different from the larger giant planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.

Click to view full size image

Here is a picture of the structure of the Earth. The picture was made at the University of Leeds.

Further googling will get you to one hit after another about Earth as a rocky or terrestrial planet.

So once again, Alohascope, what are you up to? You make no attempt whatsoever to really try to find out if your hypotheses are correct. You listen to no one. People can throw a ton of evidence at you, and you just shrug it off. In my opinion you are not interested in the universe or the solar system at all, just in your own fantasies about them. That sounds harsh, but I'm afraid I mean it. Perhaps you will change in the future, so that you become a valuable member of these boards. But for now, I don't think you belong here.

Ann

Ann I'm not up to anything except discussion. I post perhaps more than many posters on some topics because I am excited about Pluto especially becuase it broke so many barriers of status quo thinking. If you read the urls I provide you will see they are mainstream science. I am also excited about the discovery of immense reservoirs of water IN the earth and on the moon. (However, you will notice I post nothing on most topic as they hold little interest to me.) Also, if editing were allowed for guests I would not have to post as many posts, but Geckzilla has answered that suggestion.

If you have a hard time accepting my observations (waves beneath Pluto's ice, wave which warm the ice and create the pits, pits which line up in wave patterns) it could be because my powers of observation are simply unhindered by the status quo which said Pluto would be a big rock .. Pluto and its moons stunned most scientists. I was not surprised at all. If you read the urls I provided, and saw the depictions of water newly discovered IN the earth, you would see a huge amount of water IN the earth, changing the branding of 'rocky planet.' If Google's definition of 'rocky planet earth' has not changed yet, it will change soon as more and more water IN the earth is discovered through exploration for energy resources.

Ann, Status Quo hinders freedom of the mind. I do not 'join' in membership of any affiliations of any kind because that makes me a joiner of status quo. I prefer independance. Thus I do not become a "member" here. I don't intend on insulting anyone. But please, many 'Mad' scientists have been proven correct, many 'crazy' ideas have been proven true. To be called 'crazy' in the scientific community is as old as science itself. Thus, I am honored.

[Alohascope]

Alohascope, excuse me, but what are you up to really? You are posting like crazy here, and you have made more than one crazy claim, too. For example, you said that the Earth is not a rocky planet. The slightest googling effort would have told you otherwise.

Wikipedia wrote:

A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
...
Terrestrial planets have a solid planetary surface, making them substantially different from the larger giant planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.

Click to view full size image

Here is a picture of the structure of the Earth. The picture was made at the University of Leeds.

Further googling will get you to one hit after another about Earth as a rocky or terrestrial planet.

So once again, Alohascope, what are you up to? You make no attempt whatsoever to really try to find out if your hypotheses are correct. You listen to no one. People can throw a ton of evidence at you, and you just shrug it off. In my opinion you are not interested in the universe or the solar system at all, just in your own fantasies about them. That sounds harsh, but I'm afraid I mean it. Perhaps you will change in the future, so that you become a valuable member of these boards. But for now, I don't think you belong here.

Ann

Another example of how power of editing for guests would have made this second post to Ann unnecessary.

Ann your illustration does not contain a date, however, at this date in history that illustration may still hold considerable power of persuasion. But, as more and more water IN earth is discovered a new model will be made as rock is of course generally denser than water .. although some rock actually floats on water, and it is possible that kind of rock will be found along with the water. What is another of my "crazy claims?"

As far as me not reading other people's evidences, you're simply wrong, in the little evidence put forward. In the short time I have been here I have been criticized, but you are the first person that I can remember as having posted urls to substantiate your view. Chris Peterson provided his result on the effect of Nix on Pluto's tides, but he didn't provide a url to back it up, nor an equation. So .. who is at fault here? I have offended some posters here because I will not 'join' in 'membership,' but the benefits are small, the cost to independent thought processes is high.

Ann, to say that I am not interested in the universe of the solar system is totally NOT supported by my posts, which show a deep interest in cosmology. If you cannot support my solution for the pits on the ice of Pluto, perhaps you can provide some urls which disprove the evidence. You CANNOT say I did not put a lot of thought and effort into it though. AND, if I did not listen to what other posters have to say here, I would not have found the solution to those pits .. as it was another posters idea of 'heat from beneath' which I admitted in my posts which inspired my thoughts on that question.

[Alohascope]

Then again: when you watch that animation of the system long enough you see the moons lining up on one side of Pluto or the other .. that would create a lot more pull than Nix alone.

No. The animation is telling us nothing about tides. Tidally, the Pluto system is basically two bodies: Pluto and Charon. There is a very strong tidal force between the two, but since they're tidally locked in a low eccentricity orbit around each other, that tide doesn't do much work. Nix and Hydra are the only other two bodies that could produce a barely detectable tide, but that tidal force is extremely small- not enough to distort Pluto or Charon to any degree, not enough to move material, even liquid if it exists. Styx and Kerberos would have no tidal effect at all.

You see patterns in the orbits because of the complex resonances that exist. Even a perfect syzygy condition, however, would not produce any significant tidal forces. Whatever is going on with Pluto's geology, tides are almost certainly not a factor.

Chris I'll let our exchange end with your "... tides are almost certainly not a factor."

[Ann]

Ann your illustration does not contain a date, however, at this date in history that illustration may still hold considerable power of persuasion. But, as more and more water IN earth is discovered a new model will be made as rock is of course generally denser than water .. although some rock actually floats on water, and it is possible that kind of rock will be found along with the water. What is another of my "crazy claims?"

My link was to the Wikipedia article about the Earth as a rocky planet. Alohascope, are you aware of what sort of source Wikipedia is? It is maintained and updated by thousands, tens of thousands or even hundreds of thousands of members, who are adding to the entries and articles there and taking away mistakes. There are indeed cases where large groups of members disagree on an issue, and Wikipedia entries on controversial issues may change back and forth rather substantially.

But as to whether or not the Earth is a rocky planet, the Wikipedia members who think that the Earth is not predominantly rocky make up such a tiny minority that if they try to claim that the Earth is not a rocky planet, other users will delete their additions almost instantly.

You tell me that a new model of the Earth will be made. Well, thousands, or tens or thousands, or hundreds of thousands, or millions of Wikipedia members don't agree with you.

I don't agree with you either. Unlike you, I don't claim to know the future. But I understand enough of how scientists measure the mass and the density of the Earth to conclude that the Earth must be made mostly of rock, otherwise its physical properties would be radically different than what we observe them to be. For example, if the Earth was predominantly made of ice and water, it would be much less massive than we know it to be.

I don't know what made the pits of Pluto. I have no idea. Like everybody else, I am amazed at this distant, incredibly diverse and active world. And while I draw some conclusions when I see some features of Pluto, I wouldn't dream of telling everyone else that I understand the processes that made these features. How would I know that? I and everybody else are seeing Pluto for the first time. How can anyone know for sure why Pluto is the way it is, at this stage?

Scientists will spend years carefully studying the images of Pluto. They will make computer models to try to work out which models work and which don't. They will slowly agree on why Pluto is the way it is.

But you are telling me that you already know what caused all sorts of features on Pluto. Your cocksureness makes a bad impression on me.

And one thing is certain: I have greater faith the scientists who slowly, laboriously work to try to make Pluto give up its secret than I have in you, and I have greater faith in thousands, or tens of thousands, or hundreds of thousands, or even millions of members of Wikipedia than I have in you.

Ann

[geckzilla]

Thanks, Ann, that about sums it up... There is little point in continuing this line beyond that. Please simply report future posts following Aloha's pattern rather than responding.

[neufer]

Pluto updates from AGU and DPS:
Posted by Emily Lakdawalla, 2015/12/21

<<There is a huge variety of types of surfaces on Pluto. That variety relates, in part, to a variety in surface materials on Pluto. The main materials on Pluto are water ice, carbon monoxide ice, nitrogen ice, methane ice, and tholins. At the poster session, I asked geophysicist Bill McKinnon about the properties of these ices. He explained that at the 40-kelvin temperatures that prevail on Pluto, water ice is as strong and solid as rock is on Earth, but the other ices are weaker. Nitrogen and carbon monoxide ices will act very similarly on the surface (and are miscible in each other). The main difference between nitrogen and carbon monoxide on Pluto is that nitrogen is more volatile, and will turn to vapor when heated more quickly than carbon monoxide will. Both have much less strength than water ice, so should flow more readily, much as glacial ice does on Earth. Note that even though they can flow, they are still solid, and the flow we're talking about is relatively slow, in the neighborhood of several centimeters per year. Methane ice can mix into nitrogen and carbon monoxide ices as well, it's less volatile, and may be more rigid. Nitrogen and carbon monoxide ices are both denser than water ice at 40 kelvins, while methane has only half the density of water ice. Tholins are organic solids produced when solar radiation bombards these ices, and are likely the agent that produces reddish stains in various places on Pluto.>>

[MarkBour]

I'm having trouble finding any references that spell this out for me. I believe that methane ice, like water ice, is less dense than the liquid phase (depending on what exactly the methane ice is composed of, because I think they mean methane and water combinations). But I would guess that carbon monoxide ice and nitrogen ice do not share this happy property ... that instead, the solid phases are more dense than the liquid phases. Not sure how that affects flows of these substances, but it might cause somewhat different dynamics than with water ice flow.

[sallyseaver]

I'm having trouble finding any references that spell this out for me. I believe that methane ice, like water ice, is less dense than the liquid phase (depending on what exactly the methane ice is composed of, because I think they mean methane and water combinations). But I would guess that carbon monoxide ice and nitrogen ice do not share this happy property ... that instead, the solid phases are more dense than the liquid phases. Not sure how that affects flows of these substances, but it might cause somewhat different dynamics than with water ice flow.

The property that you are thinking about is called negative thermal expansion. It is commonly known to be a property of water. It is also a property of basalt due to the high concentrations of silicates; in other words, basalt expands when it cools. An article on Wikipedia (Negative_thermal_expansion) has more information on the types of substances that have negative thermal expansion.

So I did a little searching for you and found this article from August 1970: http://link.springer.com/article/10.1007%2FBF00628321. It says that "The linear-expansion coefficient calculated from these data is found to have a maximum at 19.8 K, .... A negative expansion coefficient has been observed below 8 K." Another peer-reviewed article puts the negative thermal expansion property of methane happening at 8.7 K [http://onlinelibrary.wiley.com/doi/10.1 ... 3/abstract]. But there is nothing to suggest that their research is done under the kind of low pressure associated with Pluto. Pressure matters.

According to Wikipedia, the melting point of methane is 90.7 K, so methane is solid below this point at atmospheric pressure. NASA has measured the surface pressure of Pluto to be approximately 10 microbar, that is 1 x 10^-5 bars [atmospheric pressure is 1.013 bars or 1013 mbars]. NASA has measured the black-body temperature of Pluto to be 37.5 K (Earth's mean black-body temp: 254.3 K).

Does this help your thinking?

Kudos to you for thinking about how negative thermal expansion might be influencing the surface of Pluto.

[neufer]

I did a little searching for you and found this article from August 1970: http://link.springer.com/article/10.1007%2FBF00628321. It says that "The linear-expansion coefficient calculated from these data is found to have a maximum at 19.8 K, .... A negative expansion coefficient has been observed below 8 K." Another peer-reviewed article puts the negative thermal expansion property of methane happening at 8.7 K [http://onlinelibrary.wiley.com/doi/10.1 ... 3/abstract]. But there is nothing to suggest that their research is done under the kind of low pressure associated with Pluto. Pressure matters.

• High pressure (i.e., >100MPa ~ 1000 atmospheres) matters but low pressure probably doesn't.

Water Density by Martin Chaplin

[b][size=115]The density of liquid & solid water along the liquid-solid phase line.[/size][/b]

---

Hexagonal ice is less dense than liquid water whereas the other ices found in equilibrium with water are all denser with phase changes occurring on the approach of the liquid and solid densities.

Orange = amorphous ice.

Blue = crystalline ice.

Ice III = A tetragonal crystalline ice, formed by cooling water down to 250 K at 300 MPa.

[sallyseaver]

Okay, I get your point about phase transitions for water and high pressure. But we were discussing methane. I just don't know for certain that the results published for methane at one bar (Earth's atmospheric pressure) translate to methane on Pluto where the pressure is 5 orders of magnitude less.

Do you think that with Pluto being 37.5K that most likely methane would not be cold enough to affect its density?

It's a very interesting graph regarding water. I did not know about these different types of ice and how it affected the density. Thanks!

[neufer]

Okay, I get your point about phase transitions for water and high pressure. But we were discussing methane. I just don't know for certain that the results published for methane at one bar (Earth's atmospheric pressure) translate to methane on Pluto where the pressure is 5 orders of magnitude less.

The point is that solids & liquids don't care much about low pressures...only gases do.

[MarkBour]

... (see above) ...
Does this help your thinking?
Kudos to you for thinking about how negative thermal expansion might be influencing the surface of Pluto.

Yes, the info was very helpful ... thanks!
Also, thanks to Art for the additional comments and chart.

Actually, though, I was thinking that negative thermal expansion (now that I know it's name) is so rare, that one should not assume it to be part of what's happening on Pluto. Any idea about liquid methane sloshing around under a skin of solid methane sounded unlikely to me.

In my time on APOD so far, I've seen that every place we've reached in our early exploration of the Solar system has shown fascinating new behaviors of familiar substances. It seems that many of the behaviors have come as a surprise, at least in part. Each body is a different laboratory.

[neufer]

Any idea about liquid methane sloshing around under a skin of solid methane sounded unlikely to me.

• Slosh, verb [probably blend of slop & slush] : to cause (a liquid) to move in a noisy or messy way

[b][color=#FF0000][size=110]Transmitted to Earth on Dec. 24, 2015, this image from the Long Range Reconnaissance Imager (LORRI) extends New Horizons’ highest-resolution swath of Pluto to the center of Sputnik Planum, the informally named plain that forms the left side of Pluto’s “heart.” Mission scientists believe the pattern of the cells stems from the slow thermal convection of the nitrogen-dominated ices. The darker patch at the center of the image is likely a dirty block of water ice “floating” in denser solid nitrogen, and which has been dragged to the edge of a convection cell. Also visible are thousands of pits in the surface, which scientists believe may form by sublimation.[/size][/color][/b]

---

‘X’ Marks a Curious Corner on Pluto’s Icy Plains
Jan. 7, 2016: Bill Keeter

<<“X” marks the spot of some intriguing surface activity in the latest picture of Pluto returned from NASA’s New Horizons spacecraft. “This part of Pluto is acting like a lava lamp, if you can imagine a lava lamp as wide as, and even deeper than, the Hudson Bay.” - William McKinnon, deputy lead of the New Horizons Geology Team.

Sputnik Planum is at a lower elevation than most of the surrounding area by a couple of miles, but is not completely flat. Its surface is separated into cells or polygons 16 to 40 kilometers wide, and when viewed at low sun angles (with visible shadows), the cells are seen to have slightly raised centers and ridged margins, with about 100 meters of overall height variation.

Mission scientists believe the pattern of the cells stems from the slow thermal convection of the nitrogen-dominated ices that fill Sputnik Planum. A reservoir that’s likely several miles or kilometers deep in some places, the solid nitrogen is warmed at depth by Pluto’s modest internal heat, becomes buoyant and rises up in great blobs, and then cools off and sinks again to renew the cycle.

“This part of Pluto is acting like a lava lamp,” said William McKinnon, deputy lead of the New Horizons Geology, Geophysics and Imaging team, from Washington University in St. Louis, “if you can imagine a lava lamp as wide as, and even deeper than, the Hudson Bay.”

Computer models by the New Horizons team show that these blobs of overturning solid nitrogen can slowly evolve and merge over millions of years. The ridged margins, which mark where cooled nitrogen ice sinks back down, can be pinched off and abandoned. The “X” feature is likely one of these—a former quadruple junction where four convection cells meet. Numerous, active triple junctions can be seen elsewhere in the LORRI mosaic.>>

[BMAONE23]

Well,,,if that don't look like a gigantic slug a crawlin down the trough