February 15th 20177
The other day I stumbled onto another Pluto discovery and it has opened my eyes to see things I had missed. It began with a closeup view along the North West edge of Sputnik Planitia (SP). I saw icebergs or ice blocks chipping off the land ice floating away and into the ocean of nitrogen fluid in SP. I was fascinated by this so I decided to look at the bigger picture surrounding this zone of iceberg creation.
Using the word fluid when describing these ices can be a trip point for some a couple scientists have expressed their concerns with this concept. The primary issue appears to be atmospheric pressure which is currently too low for these gasses to exist as liquids.
Using the word fluid when describing these ices can be a trip point for some a couple scientists have expressed their concerns with this concept. The primary issue appears to be atmospheric pressure which is currently too low for these gasses to exist as liquids.
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When I use the word fluid it is a relative term. My point in using the word fluid is to describe the relatively fast motion of one ice compared to the relatively slow motion of another ice hence one acts more like a fluid or liquid when compared against the same time scale of the other.
Pluto goes through Milankovitch cycles, it's poles wobble from 102 to 126 degrees creating extreme atmospheric conditions which sometimes allows Nitrogen to reach its triple point (become a liquid, solid and gas). In this video, Alan Stern (16 min mark) explains how Pluto has had atmospheric conditions due to Milankovitch cycles that would allow nitrogen to reach its triple point. |
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As an example of relative flow patterns of materials;
On Earth water flows on glacial ice, glacier's flow on silicate rock (glaciation), and rock flows on the Earth's mantle (subduction). The primary difference is how fast or over what time frame we are considering the flow's migration. So if I use the term fluid it's a relative term. But with only one image of Pluto we have no way of knowing how fast each ice is migrating only that it is obvious some ices move relative to others on much shorter time scales hence appearing fluid like compared to other ices.
Take this image as an example, one image doesn't tell you much about the relative motion of the ice.
On Earth water flows on glacial ice, glacier's flow on silicate rock (glaciation), and rock flows on the Earth's mantle (subduction). The primary difference is how fast or over what time frame we are considering the flow's migration. So if I use the term fluid it's a relative term. But with only one image of Pluto we have no way of knowing how fast each ice is migrating only that it is obvious some ices move relative to others on much shorter time scales hence appearing fluid like compared to other ices.
Take this image as an example, one image doesn't tell you much about the relative motion of the ice.
Add a couple time lapsed images and there's a whole new perspective on the mobility of these ices. These ices are fluid they are flowing but they are not a liquid. I use the words flow and fluid frequently when describing the movement of ices on Pluto.
I rarely use the word liquid when describing ices on Pluto or Charon.
But
Make no mistake ices on Pluto are in a dynamic fluid state, they move some faster than others.
I have on several occasions tried to identify the pattern of flow on the surface of SP. In some places, it's pretty easy to identify the fluid's direction of movement but in other area's it becomes really confusing as some features suggest one direction of movement while others suggest movement in the opposite direction. My best interpretation of this phenomenon is that there are layers of nitrogen existing at different temperatures just like we see in our own ocean. In addition, depending on salinity, additional barriers and layers exist in our oceans. SP may have a similar phenomenon depending on how much methane or carbon monoxide is mixed in with the nitrogen.
This likely causes temperature and density layers where fluids move in multiple directions. With this level of complexity in mind, I'm going to do my best to sort out at least the things we can see on the surface. In addition to that, on Earth, we see rip currents along beaches where the ocean water flows onto the beach then rebounds back out into the ocean. All of these factors are likely occurring on this Pluto ocean called Sputnik Planitia.
Below is the edge where relatively hot SP nitrogen is turning the land ice into icebergs right now.
The hot (relative term) fluid boiling up from below is dissolving chunks of icebergs off the land ice.
As the warm fluid melts the land ice into large ice block fragments, tholin is melted into the more liquidus fluid creating red tholin streaks like an oil slick. The oil slick of red tholin's provides some indicators identifying direction of flow.
The yellowish material intermingled with the red oil slick tholin and ice blocks seem to indicate hot fluid is flowing out away from the land ice but other surface currents are also flowing inward toward the land in various locations. These are like rip currents in Earth's oceans.
This likely causes temperature and density layers where fluids move in multiple directions. With this level of complexity in mind, I'm going to do my best to sort out at least the things we can see on the surface. In addition to that, on Earth, we see rip currents along beaches where the ocean water flows onto the beach then rebounds back out into the ocean. All of these factors are likely occurring on this Pluto ocean called Sputnik Planitia.
Below is the edge where relatively hot SP nitrogen is turning the land ice into icebergs right now.
The hot (relative term) fluid boiling up from below is dissolving chunks of icebergs off the land ice.
As the warm fluid melts the land ice into large ice block fragments, tholin is melted into the more liquidus fluid creating red tholin streaks like an oil slick. The oil slick of red tholin's provides some indicators identifying direction of flow.
The yellowish material intermingled with the red oil slick tholin and ice blocks seem to indicate hot fluid is flowing out away from the land ice but other surface currents are also flowing inward toward the land in various locations. These are like rip currents in Earth's oceans.
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The red tholin material accumulates along the edges of the polygonal mounds in the area similar to the coffee ring effect.
In the below closeup image it appears as though waves have formed in the whiter yellowish material moving outward and the waves terminate along the border where the yellow material meets the red tholin covered material. The yellow material is moving away from the land ice while the red tholin material is moving toward the land. The waves seem to imply the yellow material is hotter hence less viscous than the red stuff. Since the red stuff is thicker or more viscous it sets up a boundary between it and the more fluid yellow material. |
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The cellular or polygonal mounds near the NW shoreline on SP tend to be whiter in the center with edges covered in tholin. Conversely, the deeper we migrate into SP a reverse color pattern is displayed. Deeper into SP the red material appears to be evenly dispersed over the entire polygonal cells while the troughs display the yellow material. My guess as to why this occurs is that some of the tholin near the warmer edge is slightly lofted into the atmosphere and it deposits onto the cells further from land.
The whiter material is more fluid and hotter than the outer edges which are thicker. The polygonal mounds are likely created by convection where hotter oatmeal like material or lava lamp material is bubbled up to the middle then it cools as it flows outward to create it's red colored trough rim. The edges of the cells are thicker or colder or more viscous than the center of the cells. All this info together suggest close to land the yellow colored stuff is more fluid and hot while the red edges are cold and dense hence creating a boundary line.
At least some of the hot fluid comprising SP is entering from the NW below the surface and is boiling up from below creating the polygonal cells. The central area of SP appears to be pushing its material to the NW while some subsurface fluid from the NW is traveling SE and the two are collided at the NW edge of SP creating this churning effect breaking ice chunks off the land.
Sublimation pits or cups like we see below are seen all over SP but this is the only place I see them organized into wave patterns,
The whiter material is more fluid and hotter than the outer edges which are thicker. The polygonal mounds are likely created by convection where hotter oatmeal like material or lava lamp material is bubbled up to the middle then it cools as it flows outward to create it's red colored trough rim. The edges of the cells are thicker or colder or more viscous than the center of the cells. All this info together suggest close to land the yellow colored stuff is more fluid and hot while the red edges are cold and dense hence creating a boundary line.
At least some of the hot fluid comprising SP is entering from the NW below the surface and is boiling up from below creating the polygonal cells. The central area of SP appears to be pushing its material to the NW while some subsurface fluid from the NW is traveling SE and the two are collided at the NW edge of SP creating this churning effect breaking ice chunks off the land.
Sublimation pits or cups like we see below are seen all over SP but this is the only place I see them organized into wave patterns,
The below image extends our view deeper onto the land ice or North West of the iceberg melt site. I drew red dashes onto low land areas where the land ice is darkened and being dissolved by the subsurface hot fluid nitrogen. The blue dashes are lighter elevated plateaus or ridge lines which will eventually become broken off chunks of land ice called icebergs.
Below are yellow arrows showing how fluid is flowing out away from the land ice in a fan pattern as red tholin is pushing creating a bend in the flow.
The red arrows show how large ice chunks are breaking off and flowing away from the land.
The green lines are showing how red tholin is running off the land ice out into the deeper parts of Sputnik Planitia.
The blue arrows show a long fracture from which large ice blocks are separating.
Below is Pluto's version of a river delta and images of various river deltas on Earth.
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This is the land ice area above Pluto's river delta. Take some time to study this scene and note the low areas which are darkened by the subsurface nitrogen. Look at its pattern as it meanders NW. This whole area is an extension of the fluid that is melting the icebergs at the SP edge. Pause for a moment and study the below. Look closely at the low darker areas and how they surround brighter raised portions which may become iceberg.
Zooming out further we see this darkened discolored low land area as extending from the NW edge of SP into a series of fingers reaching deep into the land. The dark green lines (below) are an extensional pattern of the light green area which is actively breaking off chunks into the blue and red areas.
The red lines are the icebergs that are separating and floating outward to become the section of icebergs along SP western edge. Previously I thought all these bergs were moving north but the evidence of the fluid flow along with the chunks of land icebergs suggest things are somewhat stagnant but drifting out away from the land ice.
As we pull back further and see the big picture, I think this concept will become evident.
This hot zone not only extends NW but also directly west into Viking Terra. All these features are part of the same phenomenon.
It gets bigger. While Viking Terra is a bulge the area just above is dissolving and dropping in places leaving a grayish looking meandering water way look.
Same scene without lines. Study it closely and you'll be surprised by what you start to understand.
@PolishPlanetPursuer from Zooniverse pointed out an interesting land feature comparison between Inanna Fossa and Sleipnir Fossa. He expressed how fluid must have flowed on top of the surface at Piri Planitia as Inanna and Dumuzi Fossa have smooth ridges while in contrast Sleipnir Fossa at the spider has very sharp angular ridges.
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I know it may sound like it but just because I keep saying there were/are subsurface fluids running through this area shaping the landscape that doesn't mean I think there were no surface fluids at any point.
On Page 5, I postulated a theory about Piri Planitia suggesting that once it contained a fluid that flowed into Sputnik Planitia after Inanna and Dumuzi Fossa's joined the two planitias. Piri Planitia is a bit of an anomaly and not so easy to explain. An easy explanation is to say it was once filled with fluid then the fluid either sublimated away or it sunk back underground like a desert on earth or it drained via the Fractures or Fossa's into Sputnik Planitia all are possibilities. There is one other possibility, subsurface fluids eroded the underside of this land area eating away at it which created an impression as the fluid migrated underground. Is there any evidence to support that last supposition? 
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Look closely at the land area south of Piri Planitia. It looks peculiar and different than any other areas. It's puckered and wrinkled as if it is being affected by some process from below the surface. This makes me think there are some heat and perhaps chemical processes occurring below the surface chewing away at the land ice. |
The name "Tartarus" as in Tartarus Dorsa is the name of the deep abyss (hell) that is used as a dungeon of torment and suffering for the wicked and as the prison for the Titans. Tartarus is the place where, according to Plato in Gorgias (c. 400 BC), souls were judged after death and where the wicked received divine punishment.
In the heart of Siberia's boreal forest gapes a monstrous chasm local Yakutians call a "gateway to the underworld," connecting this life to the next. This is the Batagaika crater. This crater began forming in the 1960's and is believed to have developed by methane deposits in the permafrost escaping collapsing the land into a crater. Perhaps there is a similar process occurring at Piri Planitia. Methane gasses as they warm on Pluto as on Earth may be causing surface land features to collapse into depressions.
The Batagaika crater is what scientists are now calling a "megaslump": an immense void, or "thermokarst," in the geomorphology of a permafrost landscape. These sudden rifts appear when permafrost is allowed to rapidly thaw, causing scar zones to sink into the "saturated slurry." They can remain active for decades at a time. And while understandably terrifying, thaw slumps are a pretty typical feature in Arctic environments like Siberia.
Batagaika crater was formed by subsurface erosion processes suggesting Piri Planitia may as well.
In the heart of Siberia's boreal forest gapes a monstrous chasm local Yakutians call a "gateway to the underworld," connecting this life to the next. This is the Batagaika crater. This crater began forming in the 1960's and is believed to have developed by methane deposits in the permafrost escaping collapsing the land into a crater. Perhaps there is a similar process occurring at Piri Planitia. Methane gasses as they warm on Pluto as on Earth may be causing surface land features to collapse into depressions.
The Batagaika crater is what scientists are now calling a "megaslump": an immense void, or "thermokarst," in the geomorphology of a permafrost landscape. These sudden rifts appear when permafrost is allowed to rapidly thaw, causing scar zones to sink into the "saturated slurry." They can remain active for decades at a time. And while understandably terrifying, thaw slumps are a pretty typical feature in Arctic environments like Siberia.
Batagaika crater was formed by subsurface erosion processes suggesting Piri Planitia may as well.
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I'm not saying Piri Planitia didn't contain fluids on it's surface at some point, I'm simply pointing out other processes may also be taking place. Piri Planitia does have what appear to be obvious signs pointing to a previous surface fluid material once filling this basin. The fractures in the land ice look much like a river delta.
There are are, however, indicators at Viking Terra with it's bulge and in the area south of Piri Planitia with its corrosive looking landscape that suggest there may also be subsurface processes taking place. I could be totally wrong about the subsurface fluids creating a depression on the surface of Piri Planitia, its just an idea not one I'm married to but it is a possibility.
PolishPlanetPursuer is right to question the validity of this assumption my assumption seems somewhat illogical.
Before we completely abandon this idea of subsurface erosion consider these two phenomenon which occur on earth.
There are are, however, indicators at Viking Terra with it's bulge and in the area south of Piri Planitia with its corrosive looking landscape that suggest there may also be subsurface processes taking place. I could be totally wrong about the subsurface fluids creating a depression on the surface of Piri Planitia, its just an idea not one I'm married to but it is a possibility.
PolishPlanetPursuer is right to question the validity of this assumption my assumption seems somewhat illogical.
Before we completely abandon this idea of subsurface erosion consider these two phenomenon which occur on earth.
- Sink holes
- Pingos
Sink hole
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Sink hole
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On Earth, Pingo's are formed from subsurface water (fluids) and ice. Pingo's mound upwards and distend. They tend to form a pucker in the middle
Sometimes their center fully collapses but there is typically a ridge around the edges if the center collapses.
Even when they collapse flat they tend to have signs of the central pucker.
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Sometimes they collapse mostly flat.
These images suggest Piri Planitia is not a Pingo effect. If Piri Planitia were created like a pingo it would display a bulge upward then collapse downward it would tend to show a ringed outer ridge and pucker marks with a central collapsed zone. This is not what we see at Piri Planitia so no go on the pingo.
It could be a sink hole but they tend to have a nice round deep shape. I mostly agree with my friend about surface processes shaping Piri Planitia but the corrosion pattern to its south and the Viking terra bulge to the east give me pause. |
Piri Planitia is part of a larger picture of subsurface fluid flow. The big picture shows how fluid came from Venera Terra it is currently flowing into Sputnik Planitia at the NW area.
This flowing fluid is bulging Viking Terra and subsurface pressures are creating the cryovolcanoes to the east, there is evidence of bubbling fluid rising along the South Western edge of SP. And Piri Planitia is directly in line with all these subsurface processes so perhaps the land fractures Inanna and Dumuzi Fossa allowed subsurface fluids to seep onto the land ice surface at Piri Planitia while it migrated from NW to SE then Piri Planitia's surface fluid evaporated away while it drained into SP.
PolishPlanePursuer also pointed out another interesting feature of Piri Planitia. It's primarily devoid of impacts. I extended his concept into Venera Terra in this crater map below. This means Piri Planitia was soft enough to resurface into a smooth basin and perhaps more importantly Piri Planitia is also young, younger than its surroundings but older than the fluid in SP.
Thank you PolishPlanetPursuer good stuff.
This flowing fluid is bulging Viking Terra and subsurface pressures are creating the cryovolcanoes to the east, there is evidence of bubbling fluid rising along the South Western edge of SP. And Piri Planitia is directly in line with all these subsurface processes so perhaps the land fractures Inanna and Dumuzi Fossa allowed subsurface fluids to seep onto the land ice surface at Piri Planitia while it migrated from NW to SE then Piri Planitia's surface fluid evaporated away while it drained into SP.
PolishPlanePursuer also pointed out another interesting feature of Piri Planitia. It's primarily devoid of impacts. I extended his concept into Venera Terra in this crater map below. This means Piri Planitia was soft enough to resurface into a smooth basin and perhaps more importantly Piri Planitia is also young, younger than its surroundings but older than the fluid in SP.
Thank you PolishPlanetPursuer good stuff.
This image of ice sheets on earth seems to be a similar analogy to what we see in the Venera Terra area. This is similar to how it looked before it lost the hot subsurface nitrogen fluid.
In this next image of Venera Terra I've used a pink color to outline the many darkened low zones where fluid flowed between broken ice blocks. These features when looked at without the annotations look very similar to the convection polygonal cellular mounds all over SP. Venera Terra is a surface feature showing previous processes that shaped the land ice which was an underground heated fluid exactly like we see currently at SP.
I wasn't real careful about accuracy with the pink lines, instead you need to study this scene for yourself. Look carefully at the darkened low fluid areas and the ice blocks that are separated by them. Take a little time to study this image.
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This image clearly shows how this whole area was once a fluid with ice blocks looking like sheets more than blocks. This is an extension of the processes that are taking place at SP. This area only recently cooled and hardened as the crater count is low but present. This land ice is likely thin as it is in the process of freezing. That is probably why the craters are typically shallow. Impactor's break through the ice leaving a ringed indent they look like muffled impacts. |
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The thin ice and shallow impact sites demonstrate how this section of Pluto's skin or crust is thin and young. It wasn't that long ago this was fluid and the hot material moved away from this area and into SP. Sputnik Planitia is completely devoid of impacts as the material is still in a fluid form. This area is in an intermediate stage the hot fluid has left and the surface is now in the process of hardening but is thin. Pluto is really cold between 30-55 Kelvin so freezing of the crust would occur rapidly without a heat source.
If Nix came from Pluto which I'm suggesting it did then it's ejection south of SP may have led to the fluids shifting from this area over to SP. As the nitrogen filled the pit south of SP created by Nix, the fluid retreated from this area losing a large quantity of warmth creating a long vertical crack as the surface ice cooled and constricted.
If Nix came from Pluto which I'm suggesting it did then it's ejection south of SP may have led to the fluids shifting from this area over to SP. As the nitrogen filled the pit south of SP created by Nix, the fluid retreated from this area losing a large quantity of warmth creating a long vertical crack as the surface ice cooled and constricted.
Time to really step back and see the big picture.
Notice the upper yellowish orange colored diagonal ridge line created by the mountain range above the upper blue line. This forms a continuous diagonal boundary.
The lower blue line running nearly parallel follows through Piri Planitia into Viking Terra along Sputnik Planitia's western edge down through and into the deep pit.
This is all part of the same subsurface fluid movement process from the NW down into SP. The ice crust at Viking Terra is thicker hence it has held together and bulged but fractures from the upward lifting pressure of the expanded fluid and gasses. The deep pit in the south created a void which the subsurface fluids began to fill. This sucked fluid away from Venera Terra into Sputnik Planitia along its NW edge. The warm fluid broke ice blocks off the land as it filled the basin
Here's the general idea of how I think these subsurface fluids migrated based on land mass erosion and fingerprint patterns.
I see this as the fingerprint which is demonstrating how Pluto slowly came to a halt in it's axial spin and finally stopped with it's current alignment to Charon.
Then Charon was impacted at Mordor sending shards into Pluto setting off the release of material south of SP at the pit sucking the material out and away from Venera Terra. It's only 30 to 55 Kelvin out here and that cold temperature would cause the surface to freeze over rather quickly when the heat source is removed.
Of course I could be wrong with my interpretation but the fingerprint is real. It's also interesting to me how the polygonal mounds with troughs on the surface of Sputnik Planitia appear similar to the frozen fingerprint left behind at Venera Terra.
Pluto continues to confound and amaze.
Of course I could be wrong with my interpretation but the fingerprint is real. It's also interesting to me how the polygonal mounds with troughs on the surface of Sputnik Planitia appear similar to the frozen fingerprint left behind at Venera Terra.
Pluto continues to confound and amaze.
