March 9th, 2016
Edited Sept 6th, 2017
Edited Sept 6th, 2017
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This is dry ice, frozen CO2 gas, solid Carbon Dioxide. On earth it converts from a solid directly into a gas without becoming a liquid. The process is very much like a liquid evaporating into a gas except its a solid evaporating directly into a gas while skipping the liquid phase.
This process is called sublimation. Sublimation is an endothermic reaction (absorbs energy) meaning energy has to be present for sublimation to occur. Nitrogen gas, which we breath on earth, is a solid toothpaste consistent ice on Pluto and it sublimates when it warms to the correct temperature/pressure. Sublimated solid nitrogen (along with carbon monoxide and Methane) becomes Pluto's atmosphere. |
Surface temperatures on Pluto range from 35-55 Kelvin. This temperature increases to 110 K at higher atmospheric elevations up to 18 miles (30 km) then the temperature begins to drop.
Pluto takes 248 years to orbit the sun. The north pole is angled toward the sun for half that time and away for the other half. Pluto's north pole is dark for 124 years and then lit for 124 years, sorta. This gives Pluto seasons. Half of Pluto's year (124 earth years) the north pole experiences winter where it gets really cold and sublimation slows to a crawl. In Pluto's summer years gasses are released into the atmosphere then in the fall and winter years these gasses fall out of the atmosphere like snow onto the north pole. Pluto cycles forward 124 years to its summer then sublimation and UV exposure increase. The north pole mountain ranges begin to bask in the UV radiation creating thin layers of tholin which appear to develop deeper at higher elevations.
Pluto takes 248 years to orbit the sun. The north pole is angled toward the sun for half that time and away for the other half. Pluto's north pole is dark for 124 years and then lit for 124 years, sorta. This gives Pluto seasons. Half of Pluto's year (124 earth years) the north pole experiences winter where it gets really cold and sublimation slows to a crawl. In Pluto's summer years gasses are released into the atmosphere then in the fall and winter years these gasses fall out of the atmosphere like snow onto the north pole. Pluto cycles forward 124 years to its summer then sublimation and UV exposure increase. The north pole mountain ranges begin to bask in the UV radiation creating thin layers of tholin which appear to develop deeper at higher elevations.
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Sublimation
We see the effects of sublimation on Pluto at Sputnik Planitia.
The air you breath on earth is 78% nitrogen as a gas but nitrogen on Pluto is frozen solid except when it has just enough energy to sublimate into a gas. The sublimation process at Sputnik Planum looks like inverted hollow half shelled bubbles. Look at these hollow half spheres or cups they look like popped inverted bubbles and may be the result of heat rising from below or Pluto's climate. |
Some scientists suggest there is too much nitrogen released from Pluto's atmosphere into space for impacts to have grown Pluto at a rate that would keep up with the outward flow of nitrogen. In other words, impacts haven't occurred frequently enough to supply Pluto with as much nitrogen in its atmosphere to keep its land mass in tact. It would have fizzled or sublimated out all its gas and gone puff, no more Pluto but there is a Pluto.
When New Horizons flew past Pluto, Pluto was near its perihelion or closest to the sun but heading out and away from the Sun.
Pluto had a long quiet time in which thick tholin tar was laid around the globe. This layer of tar would have prevented much of the nitrogen contained as ice from sublimating into an atmosphere. I am suggesting that the atmosphere is a consequence of the existence of Sputnik Planum which came into existence rapidly and recently. Sputnik Planum in conjunction with the northern drifting methane snow, have combined to create the atmosphere on a seasonal basis. Prior to SP there may not have been an atmosphere to speak of, if there was, the tholin would have helped trap the methane underneath. This would have kept Pluto growing from impacts while giving up less of its surface ices to sublimation.
As of March 17 2016 NASA has corrected their understanding of escaped gasses from Pluto.
Quote added March 20, 2016
Above the surface, scientists discovered Pluto’s atmosphere contains layered hazes, and is both cooler and more compact than expected. This affects how Pluto’s upper atmosphere is lost to space, and how it interacts with the stream of charged particles from the sun known as the solar wind. “We’ve discovered that pre-New Horizons estimates wildly overestimated the loss of material from Pluto’s atmosphere,” said Fran Bagenal, from the University of Colorado, Boulder, and lead author of the particles and plasma paper. “The thought was that Pluto’s atmosphere was escaping like a comet, but it is actually escaping at a rate much more like Earth’s atmosphere.”
Pluto had a long quiet time in which thick tholin tar was laid around the globe. This layer of tar would have prevented much of the nitrogen contained as ice from sublimating into an atmosphere. I am suggesting that the atmosphere is a consequence of the existence of Sputnik Planum which came into existence rapidly and recently. Sputnik Planum in conjunction with the northern drifting methane snow, have combined to create the atmosphere on a seasonal basis. Prior to SP there may not have been an atmosphere to speak of, if there was, the tholin would have helped trap the methane underneath. This would have kept Pluto growing from impacts while giving up less of its surface ices to sublimation.
As of March 17 2016 NASA has corrected their understanding of escaped gasses from Pluto.
Quote added March 20, 2016
Above the surface, scientists discovered Pluto’s atmosphere contains layered hazes, and is both cooler and more compact than expected. This affects how Pluto’s upper atmosphere is lost to space, and how it interacts with the stream of charged particles from the sun known as the solar wind. “We’ve discovered that pre-New Horizons estimates wildly overestimated the loss of material from Pluto’s atmosphere,” said Fran Bagenal, from the University of Colorado, Boulder, and lead author of the particles and plasma paper. “The thought was that Pluto’s atmosphere was escaping like a comet, but it is actually escaping at a rate much more like Earth’s atmosphere.”
In this paper called The surface age of Sputnik Planum, Pluto, must be less than 10 million years, David Trilling indicates there are three mechanism by which the surface of SP could be getting turned over on a time scale of less than 10 million years.
Convective overturn is the description NASA seems to favor but I struggle with this one and I'll explain why shortly.
Cryovolcanism seems to fit what I see more than any other description.
First I'll explain why viscous relaxation does not seem to accurately portray what is seen.
- Viscous Relaxation
- The surface material flows to relieve any topographic features and horizontal and vertical stresses.
- Convective Overturn
- The difference in density between nitrogen ice at 40 K (Pluto surface temperature) and 60 K (the temperature near the base of the “cryo-lithosphere” just below the nitrogen melting temperature) is around 5%
- Cryovolcanism
- The assumption here is that at the base of the SP surface layer, which we again take to be on the order of 10 km, there is
(perhaps partial) melting of nitrogen ice. This liquid material, which is under pressure, could be extruded to the surface through local cracks (presumably the same cell boundaries described above) and fill in any negative topography before freezing. This mechanism requires that the temperature at the base of the SP surface layer be around 63 K, at which temperature solid nitrogen melts, compared to the surface temperature of 38 K.
- The assumption here is that at the base of the SP surface layer, which we again take to be on the order of 10 km, there is
Convective overturn is the description NASA seems to favor but I struggle with this one and I'll explain why shortly.
Cryovolcanism seems to fit what I see more than any other description.
First I'll explain why viscous relaxation does not seem to accurately portray what is seen.
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Certainly there must be some form of viscous relaxation taking place in order for objects to impact the surface then disappear sorta like quick sand swallowing an object except in this case it's more like slow sand or as Alan Stern describes it the nitrogen ocean has a toothpaste consistency. In this image you can see how there are troughs creating cells. To suggest that viscous relaxation is the cause of this surface is to ignore these troughs. Some process is creating them. If you look close at this image one thing that seems to be taking place regularly is the more aggressive looking sublimation cups seem to cluster around the troughs. while further away from the troughs the sublimation cups tend to lighten up significantly. The more sublimation taking place the more likely it is these areas are warmer than the areas with less sublimation cups. Central parts of the cells are not smooth but the sublimation process appears to be significantly subdued compared to the zones around the troughs. Sometimes an area without a clearly defined trough will have aggressive sublimation pits which seem to be turning into a trough but not quite there yet. Sometimes the heat that makes the sublimation pits is strong enough such that the surface near the most aggressive pit formation becomes completely smoothed over. In other words, the fluid is so warm it can't even retain the shape of the sub cup. |
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More or Less
This is the general idea.
Areas with more pits tend to line up near areas where troughs exist or seem to be about to form. It seems as though the aggressive action of the pits precede the formation of the troughs. This suggest heat is welling up at these spots which in turn forms the troughs. In other words, the troughs are the byproduct of their alignment with a source of heat from below indicated by the sublimation cup's size and quantity. |
Take a look at this below image where an X is forming.
The section just below the X looks like it is actively bubbling with heat such that the surface is mostly smooth with large inverted bubbles or sublimation cups. Large quantity and large sized pits equal more aggressive bubbling or a hotter zone. The upper left arm of the X is forming a trough connection (green text arrows) with the long diagonal trough. Lots of cups line the edges of the troughs while conversely fewer and smaller in size cup's exist further away from the troughs. Fewer smaller cups indicate colder less active zones.
In and Out and In and Out and In and Out,
This section needs some correction
Pluto and Charon's poles which are aligned perpendicular to their mutual spin orbital plane is at an oblique angle of 118 degrees relative to their 17 degree orbital path around the sun. Pluto reaches perihelion (closest to sun) with its South pole facing the sun. When the north pole is facing the sun it is furthest away from the sun's energy. Therefore, more sublimation is likely to occur on the south pole as Pluto reaches perihelion (nearest to sun) rather than at the north poles during aphelion (furthest from sun).
Pluto and Charon spin around each other with the north poles facing down and away from their direction of travel as they approach the Kuiper belt with the south poles facing forward and towards any potential impacting objects. They rotate around a barycenter (shared gravitational point in space). Look at them like a round clock flying through space backwards as it approaches the Kuiper belt.
On this clock the minute and hour hands rotate around a central point in space and the clock's rear (south poles) point towards their direction of travel as they enter the Kuiper belt. On approach to aphelion (furthest point from the sun) where they begin their return trip, the edge of the clock leads as it passes through aphelion then the front of the clock is angled forward (the north poles are now leading) as the clock face now leads the charge out of the Kuiper belt, the south poles are now at the rear.
How about this scenario, I call it the two step boogie.
Pluto/Charon do the Michael Jackson moon walk as they enter the Kuiper belt, then they do a two step side shuffle through aphelion finally to waltz their way out of the the Kuiper belt to the applause of all.
Pluto/Charon's south poles lead as they enter the Kuiper belt and the north poles lead on the way out.
Describing all the angles gets confusing so there's a jumbled mess of a diagram below but if you study it, the picture should be clear. To make things more confusing Pluto/Charon are always spinning while changing angles of approach and direction.
Pluto and Charon spin around each other with the north poles facing down and away from their direction of travel as they approach the Kuiper belt with the south poles facing forward and towards any potential impacting objects. They rotate around a barycenter (shared gravitational point in space). Look at them like a round clock flying through space backwards as it approaches the Kuiper belt.
On this clock the minute and hour hands rotate around a central point in space and the clock's rear (south poles) point towards their direction of travel as they enter the Kuiper belt. On approach to aphelion (furthest point from the sun) where they begin their return trip, the edge of the clock leads as it passes through aphelion then the front of the clock is angled forward (the north poles are now leading) as the clock face now leads the charge out of the Kuiper belt, the south poles are now at the rear.
How about this scenario, I call it the two step boogie.
Pluto/Charon do the Michael Jackson moon walk as they enter the Kuiper belt, then they do a two step side shuffle through aphelion finally to waltz their way out of the the Kuiper belt to the applause of all.
Pluto/Charon's south poles lead as they enter the Kuiper belt and the north poles lead on the way out.
Describing all the angles gets confusing so there's a jumbled mess of a diagram below but if you study it, the picture should be clear. To make things more confusing Pluto/Charon are always spinning while changing angles of approach and direction.
NASA created all the black lines and planetary balls. I created all the blue and red lines and light blue Kuiper belt balls
Based on previous observations, the 8 O-Clock impact on Charon that cracked Charon like an egg shell along a diagonal path to the 2 O-Clock POP, makes me think this impact occurred while Pluto/Charon were approaching aphelion and beginning their entrance into the Kuiper belt. Charon was likely entering the Kuiper belt when impacted at the 8 O-Clock position. This angle seems the most likely for this impact to occur, Many more trips around the sun continued without incident while passing through the Kuiper belt.
However, some time later during one of Pluto/Charon's trips as they were exiting through the Kuiper belt with their north pole's leading, Charon slammed into some objects with her north pole.
I'm pretty sure I got all that correct.
Next up!
Shock Waves
However, some time later during one of Pluto/Charon's trips as they were exiting through the Kuiper belt with their north pole's leading, Charon slammed into some objects with her north pole.
I'm pretty sure I got all that correct.
Next up!
Shock Waves
