February 26th 2016
Significant editing on June 15th 2017
Significant editing on June 15th 2017
The Rocky Core Model
Jupiter moon - Europa's rocky core model. Take note of how thin the water layer is (left image) compared to the rocky interior.
Above is an example of the rocky core model of Jupiter's moon Europa which is believed to be fueled and created by tidal forces. Pluto/Charon are tidally locked into a near perfect circular orbit suggesting they don't experience these tidal flexing forces (or do they?).
The rocky core model with an ocean of liquid and an ice crust, is based primarily on info related to orbiting bodies that have displayed some form of heat absorption (i.e. tidal flexing, resonance) that allows for melting the rock hard ice and letting the heavier elements separate out to become dirt, rock and metals contained within a core. While this is a reasonable model for bodies that have some obvious form of energy generation as with tidal flexing, resonant pulses or sun light, these conditions seem to be missing from the Pluto/Charon system.
On Pluto, there is no obvious current tidal flexing (or is there?), there's not enough energy from the sun, the temperature varies seasonally from 35 to 60 K, the only energy appears to come from impacts or possibly gravitational torque as Pluto's axis wobbles. Because of this wobble Pluto's atmospheric pressure is high enough every 2.4 million years for nitrogen to actually reach its triple point where it can exist as a gas, liquid and solid similar to water on Earth. Below Pluto's surface where nitrogen is insulated from the cold and vacuum of space and experiences increased pressure's (in turn heat) and possibly even a tiny amount of residual heat from gravitational torque nitrogen may experience conditions which allow it to act as a magma or lava.
Movement is energy, energy translates to heat, variations in movement translate to variations in levels of heat which in turn translates to variations in geological activity.
The rocky core model with an ocean of liquid and an ice crust, is based primarily on info related to orbiting bodies that have displayed some form of heat absorption (i.e. tidal flexing, resonance) that allows for melting the rock hard ice and letting the heavier elements separate out to become dirt, rock and metals contained within a core. While this is a reasonable model for bodies that have some obvious form of energy generation as with tidal flexing, resonant pulses or sun light, these conditions seem to be missing from the Pluto/Charon system.
On Pluto, there is no obvious current tidal flexing (or is there?), there's not enough energy from the sun, the temperature varies seasonally from 35 to 60 K, the only energy appears to come from impacts or possibly gravitational torque as Pluto's axis wobbles. Because of this wobble Pluto's atmospheric pressure is high enough every 2.4 million years for nitrogen to actually reach its triple point where it can exist as a gas, liquid and solid similar to water on Earth. Below Pluto's surface where nitrogen is insulated from the cold and vacuum of space and experiences increased pressure's (in turn heat) and possibly even a tiny amount of residual heat from gravitational torque nitrogen may experience conditions which allow it to act as a magma or lava.
Movement is energy, energy translates to heat, variations in movement translate to variations in levels of heat which in turn translates to variations in geological activity.
The Galilean moons. From left to right, in order of increasing distance from Jupiter: Io, Europa, Ganymede, Callisto
The Four Galilean Moons of Jupiter
|
Jupiter's inner four Galilean moons from nearest to furthest are Io, Europa, Ganymede and Callisto.
These four Galilean moons are so named because Galileo discovered them and witnessed them revolving around Jupiter demonstrating all objects do not revolve around the Earth. The Roman Catholic Church via the inquisition tortured and killed anyone that opposed their Earth centered view of the solar system. In 1543 Copernicus, to avoid torture wisely on his death bed, published his Sun centered model of our solar system. In 1610 the Roman Catholic church found Galileo guilty of heresy for sharing Copernicus' Sun centered view. The church, however, allowed Galileo the opportunity to recant his view and only imprisoned him for life. The density of a body gives a rough idea of how much of its compositional material is water, silicate rock or iron. Water's density is considered to be one gram per cubic centimeter, rock is about 3 g/cm3 while iron is 7.86. Earth's density is 5.514, the Moon is 3.346, Mars is 3.933, Tythes is 0.98. From this we can draw some basic conclusions. Saturn's moon Tythes is pretty much completely water ice with no rock or iron while Mars has more dense materials than our moon and likely has a small iron core relative to Earth. |
|
Io (eye-ohh)
Io is the closest Galilean moon to Jupiter and experiences the greatest degree of tidal flexing and resonance with Europa and Ganymede as it orbits near then far from Jupiter with pulsating resonances. Tidal flexing along with resonant interactions with Europa and Ganymede make Io the most volcanically active body in our solar system. 
|
Active volcanoes erupting on Io
|
|
Io was, in all probability, constructed of the same stuff as the other Galilean moons meaning it was once an ice ball like Europa, Ganymede and Callisto but all the ice and lighter materials have been evaporated away making Io the densest moon in the solar system at 3.528 g/cm3. This tidal flexing and resonant pulsing of Io is so strong it is even liquefying rock, turning it into magma. |
Io is about one third the size of Earth and has over 400 active volcanoes while Earth has only 60. Io's lava is ultramafic meaning it is really hot 1,200º C or 2,192º F at the surface compared to Earth's lava which is around 900º C or 1,652º F at the surface. Io's extreme heating from tidal flex energy has evaporated away the lighter elements like water and volatile gasses leaving behind the heavier dense materials like silicate rock which will continue to reduce down to denser metals similar to what we see at Mercury.
It's like leaving a cake in the oven for too long and heating all the moisture out of it till it becomes a hard lump of burnt dried carbon. Each Galilean moon is in a different stage of cooking similar to the four rocky planets (Mercury, Venus, Earth & Mars) near the Sun.
It's like leaving a cake in the oven for too long and heating all the moisture out of it till it becomes a hard lump of burnt dried carbon. Each Galilean moon is in a different stage of cooking similar to the four rocky planets (Mercury, Venus, Earth & Mars) near the Sun.
|
Europa
The 2nd closest Galilean moon to Jupiter is Europa and it has the smoothest surface in the solar system meaning its ice surface is renewed frequently and too thin to sustain mountains or significant uplift making its surface young. Cracks exist in its icy crust which spew out plumes of water meaning the hot core is heating the thin layered water ocean below. Europa has a density of 3.013 g/cm3) making it more rock than water ice hence there is a thin layer of water between the ice crust and hot silicate rock mantle. Most of Europa's water has been cooked away so it is small and primarily rock. |
The tidal flex energy is light enough so that Europa has not lost all of its lighter materials such as water but that energy is slowing burning off Europa's gasses hence it is the smallest of the Galilean moons with the largest proportionally sized rock/iron core. However, Europa's tidal flex energy is strong enough to keep its ice crust thin and push minerals from below up and onto the surface as can be seen in the cracks.
While Europa has held onto its icy crust with a thin ocean layer, its surface is actively fractured spewing plumes of water heavily laden with minerals from internal heat created by tidal flexing. Eventually Europa will be nothing more than a ball of rock similar to but not as volcanically active as Io.
While Europa has held onto its icy crust with a thin ocean layer, its surface is actively fractured spewing plumes of water heavily laden with minerals from internal heat created by tidal flexing. Eventually Europa will be nothing more than a ball of rock similar to but not as volcanically active as Io.
|
Ganymede
Ganymede has enough tidal flex energy to liquefy the interior ices allowing for the development of a rocky core which is about the same size as Europa's with the primary difference being Ganymede hasn't lost such a large portion of it's water ice relative to the core. Lower flex (heat) energy means less of the water ice and volatiles have been burned or boiled off. This means Ganymede has a comparatively huge ocean relative to the rocky core. Because of this ratio disparity, the outer mantle remains intact sealing the interior away from space. |
|
The core doesn't receive enough flexing energy to heat the vast ocean to the point it can create fractures in the ice crust and spew out plums of water into space.
Ganymede is the largest moon in the solar system and is even 8% larger than the planet Mercury. Ganymede's density is 1.936 g/cm3 meaning it has retained more of its ices and water relative to its metals and rock than Europa. Ganymede has the lowest moment of inertia of all the solid bodies in the solar system presumably because of the vast ocean of water.
Tidal flexing at this distance from Jupiter produces a rocky core by separating out the denser materials from the icy lighter materials but the heat energy created is not sufficient to penetrate from the core through the vast ocean to the outer layered crust of ice. This has the effect of sealing, trapping and retaining the water and volatiles behind a wall of frozen solid crustal ice.
Ganymede is the largest moon in the solar system and is even 8% larger than the planet Mercury. Ganymede's density is 1.936 g/cm3 meaning it has retained more of its ices and water relative to its metals and rock than Europa. Ganymede has the lowest moment of inertia of all the solid bodies in the solar system presumably because of the vast ocean of water.
Tidal flexing at this distance from Jupiter produces a rocky core by separating out the denser materials from the icy lighter materials but the heat energy created is not sufficient to penetrate from the core through the vast ocean to the outer layered crust of ice. This has the effect of sealing, trapping and retaining the water and volatiles behind a wall of frozen solid crustal ice.
|
Callisto
Callisto experiences the least amount of tidal flexing in the Jupiter system since it is farther out from Jupiter and is not sandwiched between other large resonant bodies. Callisto also doesn't show any signs of active land ice geology, Callisto is considered to be partially differentiation (partial rocky core). The mean temperature on Callisto is 134 Kelvin. Callisto is nearly the same size (about 99%) as Mercury but is only one third as dense at 1.834 (Mercury's density is 5.427) . Mercury is close to and heated by the Sun and is also in an elliptical orbit causing tidal flex these conditions on Mercury have done to it what an elliptical orbit and resonance around Jupiter has done to Io. |
As a body's orbital path extends further out from Jupiter, the strength and energy from resonance and tidal flexing dissipates. The rocky core model also breaks down with dissipating energy input. Callisto's density is 1.834 meaning it is roughly half ice and half rock, it is cold and has little tidal flex energy so the rock may be partially separated out. The silicate rock and metals are suspended, frozen in rock ice. No tidal flex and no resonant frequencies equals little or no separation between minerals and volatiles since without heat energy volatile gasses can become solid as rock suspending the minerals in a crystalline prison.
Updated 4/7/2016
Callisto may have a small rocky core but may not, it is considered partially differentiated or mostly uniform.
Here's a quote from Wikipedia
The partial differentiation of Callisto (inferred e.g. from moment of inertia measurements) means that it has never been heated enough to melt its ice component... In other words, Callisto is only partially differentiated. The density and moment of inertia are compatible with the existence of a small silicate core in the center of Callisto. The radius of any such core cannot exceed 600 km, and the density (of the core) may lie between 3.1 and 3.6 g/cm3. Callisto's interior is in stark contrast to that of Ganymede, which appears to be fully differentiated...Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3,
Updated 4/7/2016
Callisto may have a small rocky core but may not, it is considered partially differentiated or mostly uniform.
Here's a quote from Wikipedia
The partial differentiation of Callisto (inferred e.g. from moment of inertia measurements) means that it has never been heated enough to melt its ice component... In other words, Callisto is only partially differentiated. The density and moment of inertia are compatible with the existence of a small silicate core in the center of Callisto. The radius of any such core cannot exceed 600 km, and the density (of the core) may lie between 3.1 and 3.6 g/cm3. Callisto's interior is in stark contrast to that of Ganymede, which appears to be fully differentiated...Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3,
Jupiter moons in order of distance Io, Europa, Ganymede, Callisto. Note how closely matched the core's are compared to water ice which has been heated to evaporation.
|
There is very little energy from tidal flexing as Callisto is tidally locked to Jupiter (like Pluto is to Charon), consequently the "Rocky Core" or "Differentiated" Model begins to break down at this distance from Jupiter.
For full differentiation to take place at these temperatures some form of heat energy is required otherwise the rock stays suspended (at least partially) in the rock hard ice. |
Consider how much further away from any energy source Pluto/Charon reside and how unlikely it is that the water ice on Pluto is actually melted into an ocean of water or providing heat to separate silicate rock from ice rock. Pluto's silicate core is at most 65% the mass of Pluto and its radius is 40% its volume according to Bill McKinnon, 40% of Pluto's radius of 1.187 km indicates its largest potential core size is equal to 475 km but with partial differentiation it would be much smaller similar to what we see with Callisto.
Update Aug 18th, 2017 found this paper quoting Bill McKinnon on the volume of Pluto's rock 40% compared to its mass of 65%.
Thermal evolution of Pluto and implications for surface tectonics and a sub-surface ocean. By Guillaume Robuchon, Francis Nimmo
Pluto’s ice/rock+ice ratio is supposed to be about 0.65 (McKinnon et al., 1997) and for a differentiated Pluto the silicate core would be roughly 40% of the volume. The radiogenic heating provided by the core can potentially melt the mantle ice and form a subsurface ocean (Hussmann et al., 2006; McKinnon, 2006)
That means the physical radius of Pluto's rocky core if fully differentiated is 40% the volumetric radius of Pluto or 1,187 X 0.40 = 475 km.
Callisto has a radius of 2,410 km, 50% of which is silicate rock, if fully differentiated it's core would be 1,205 km but Wiki says it cannot exceed 600 km meaning it is partially differentiated determined by its moment of inertia of 0.359. Callisto with a 600 km core size is about 25% its radius. If we apply the same logic to Pluto with the same density and colder temperatures then it's core radius would be about 297 km. This is a tiny core which NASA is trying to suggest is still radioactively hot after 4 byr, even though, according to Francis Nimmo you need a core of at least 1,000 km to even be potentially capable of being radioactively hot today. No matter how you calculate it, Pluto's core always comes up far short of the F. Nimmo required 1,000 km radius to be radioactively hot.
These four Galilean moons probably started off proportionally with similar materials but higher levels of heat energy have burned off the lighter materials forming a transitional pattern. There is a trend of decreasing density as these moon's orbital locations exist farther from an energy source which can act to burn off the large quantities of volatile gasses leaving behind the more dense materials like rock and iron.
The amount of imparted energy from the Sun or Jupiter created by radiant heat, tidal flex or resonant pulses will dictate the formation of icy bodies, it will determine whether differentiation occurs as well as the ratios of water, ice, rock and metals.
How does the moment of inertia help us understand the distribution of mass within a planet?
Wiki says
the moment of inertia factor or normalized polar moment of inertia is a dimensionless quantity that characterizes the radial distribution of mass inside a planet or satellite.
The moment of inertia (MOI) is supposed to be able to characterize the distribution of mass in a planet but its value is dependent on assumptions made about the mass in the first place.
Update Aug 18th, 2017 found this paper quoting Bill McKinnon on the volume of Pluto's rock 40% compared to its mass of 65%.
Thermal evolution of Pluto and implications for surface tectonics and a sub-surface ocean. By Guillaume Robuchon, Francis Nimmo
Pluto’s ice/rock+ice ratio is supposed to be about 0.65 (McKinnon et al., 1997) and for a differentiated Pluto the silicate core would be roughly 40% of the volume. The radiogenic heating provided by the core can potentially melt the mantle ice and form a subsurface ocean (Hussmann et al., 2006; McKinnon, 2006)
That means the physical radius of Pluto's rocky core if fully differentiated is 40% the volumetric radius of Pluto or 1,187 X 0.40 = 475 km.
Callisto has a radius of 2,410 km, 50% of which is silicate rock, if fully differentiated it's core would be 1,205 km but Wiki says it cannot exceed 600 km meaning it is partially differentiated determined by its moment of inertia of 0.359. Callisto with a 600 km core size is about 25% its radius. If we apply the same logic to Pluto with the same density and colder temperatures then it's core radius would be about 297 km. This is a tiny core which NASA is trying to suggest is still radioactively hot after 4 byr, even though, according to Francis Nimmo you need a core of at least 1,000 km to even be potentially capable of being radioactively hot today. No matter how you calculate it, Pluto's core always comes up far short of the F. Nimmo required 1,000 km radius to be radioactively hot.
These four Galilean moons probably started off proportionally with similar materials but higher levels of heat energy have burned off the lighter materials forming a transitional pattern. There is a trend of decreasing density as these moon's orbital locations exist farther from an energy source which can act to burn off the large quantities of volatile gasses leaving behind the more dense materials like rock and iron.
- High energy at Io boils off all water ices and volatiles leaving behind boiling molten evaporating rock.
- Medium-high energy at Enceladus separates ice from rock forming a proportionally large hot rocky/iron core with a tiny ocean which creates an actively fracturing thin crust and an overall small diameter (heavily evaporated) moon.
- Medium-Low energy at Ganymede creates a relatively small core with a huge ocean and sealed crust with most of the volatile's and ices still contained within the large diameter moon (less evaporation).
- Low energy at Callisto only allows for partial separation of rock from ice, there probably isn't an ocean since there's no hot core without which the surface is inactive and the oldest surface in the solar system.
The amount of imparted energy from the Sun or Jupiter created by radiant heat, tidal flex or resonant pulses will dictate the formation of icy bodies, it will determine whether differentiation occurs as well as the ratios of water, ice, rock and metals.
How does the moment of inertia help us understand the distribution of mass within a planet?
Wiki says
the moment of inertia factor or normalized polar moment of inertia is a dimensionless quantity that characterizes the radial distribution of mass inside a planet or satellite.
The moment of inertia (MOI) is supposed to be able to characterize the distribution of mass in a planet but its value is dependent on assumptions made about the mass in the first place.
|
The only moment of inertia value I found for Pluto was in this paper and is assumed to be 0.310. but this value changes depending on various assumptions contained within the paper. If the core is assumed to be a metal ball with a radius of 368 km, the moment of inertia changes to 0.290. This chart lists some calculated moment of inertia values for some planets and moons including Callisto. I was hoping the moment of inertia would help explain Pluto's mass distribution but what it seems to do is reflect assumptions we choose to feed into a formula. |
|
|
|
The moment of inertia controls the rate at which a planet spins and the location of the spin axis depend on the distribution of mass in each body... objects with more mass at the center have lower moments of inertia.
Objects with lower moments of inertia spin faster than objects with high moments of inertia. Pluto's moment of inertia is complicated because it's spin rotation is locked to Charon. They take 6.3875 days or 153.3 hours to rotate around their barycenter. In this video, objects with solid cores (low MOI) roll down the board faster than hollow cored tubes (high MOI). |
Theoretical Moon core
|
It would then appear, Pluto should have a higher moment of inertia than Earth (spin of 24 hrs) yet lower than the moon (spin of 29.5 days) placing it between 0.3307 and 0.3929. Mercury is supposed to have a 70% metal core with a 30% silicate rock mantle with a density of 5.427 g/cm3. |
Theoretical Pluto core
|
Mercury has a large proportion of iron mass at it's center so one would think it would have a low moment of inertia and spin fast but instead it takes 175.97 days to rotate on its axis. Obviously other factors are at play and one can't simply say that MOI determines a planet's core.
I am left questioning how much some of these concepts actually help us grasp the true nature of Pluto. The one thing I completely understand is that assumptions are required in order to develop figures such as planetary moment's of inertia.
I am left questioning how much some of these concepts actually help us grasp the true nature of Pluto. The one thing I completely understand is that assumptions are required in order to develop figures such as planetary moment's of inertia.
|
Moving on to more easily understood and perhaps reliable factors of comparison.
Nitrogen on Pluto can flow (depending on pressure) at around 64 K while methane on Titan can flow at around 94 K and water needs to be around 273 K (mix in ammonia and water can be a syrupy liquid at temperatures as low as 173K). More specifically these compounds reach their triple point at particular temperatures combined with particular pressures. Nitrogen is the only material with observational evidence of being a fluid on Pluto and it requires far less energy than methane and water to flow or transition between a solid, gas and liquid state. |
|
Mainstream scientists want us to believe that Callisto has a uniform core while Pluto is differentiated and that this theoretical core is radioactively hot after 4 byr which has created a subsurface water ocean on Pluto. This theoretical core, at most, could only have a radius of 475 km while Pluto and Charon are tidally locked into near perfect circular orbits producing no tidal flex energy. To become a liquid, water needs far more energy than is produced at Pluto.
Callisto is tidally locked (no tidal flex energy) to Jupiter, twice the size of Pluto, 8 times the mass, nearly identical density with temperatures averaging 134 Kelvin which is 100 K warmer than Pluto. All this info says Pluto is more likely than Callisto to be uniform.
Callisto is warmer than Pluto is not considered to be fully differentiated or have a radioactively hot core but Pluto is. Pluto is tidally locked to Charon with a circular orbit, has a density of 1.86 g/cm3, temperatures of 35 K to 65 K and a radius of 1,187 km. Callisto's surface is considered the oldest in the solar system while Pluto has some of the youngest. Scientists suggest the explanation for this is that Pluto is fully differentiated with a radioactively hot core creating oceans of water, I don't think so.
Nitrogen on Pluto can reach temperatures and pressures that allow it to transition between all three states. Methane appears to be in an atmospheric gas vapor and snow solid via sublimation but no liquid state. Water on the other hand is rock hard land ice and even when mixed with ammonia requires more energy than is likely possible on Pluto to become an ocean. I don't have experimental evidence to prove this but getting ammonia infused water at 173 K to a fluid state where temperatures are at most 66 K would require pressures greater than Pluto can provide. I wish I could prove it mathematically, perhaps someday someone will.
Callisto is tidally locked (no tidal flex energy) to Jupiter, twice the size of Pluto, 8 times the mass, nearly identical density with temperatures averaging 134 Kelvin which is 100 K warmer than Pluto. All this info says Pluto is more likely than Callisto to be uniform.
Callisto is warmer than Pluto is not considered to be fully differentiated or have a radioactively hot core but Pluto is. Pluto is tidally locked to Charon with a circular orbit, has a density of 1.86 g/cm3, temperatures of 35 K to 65 K and a radius of 1,187 km. Callisto's surface is considered the oldest in the solar system while Pluto has some of the youngest. Scientists suggest the explanation for this is that Pluto is fully differentiated with a radioactively hot core creating oceans of water, I don't think so.
Nitrogen on Pluto can reach temperatures and pressures that allow it to transition between all three states. Methane appears to be in an atmospheric gas vapor and snow solid via sublimation but no liquid state. Water on the other hand is rock hard land ice and even when mixed with ammonia requires more energy than is likely possible on Pluto to become an ocean. I don't have experimental evidence to prove this but getting ammonia infused water at 173 K to a fluid state where temperatures are at most 66 K would require pressures greater than Pluto can provide. I wish I could prove it mathematically, perhaps someday someone will.
A Rocky ICE Model
|
I just read a paper called Internal structure of Pluto and Charon with an iron core in which an assumption about Pluto is made. The core of Pluto in this paper is assumed to be iron and at one point it was a ball of molten iron (shesh are you kidding me?). Shaking my head, I ask how do we get to a molten iron core at Pluto? Quote; But very early on Pluto was presumably hotter and the core molten. (assume it to be so and it is so. Voila molten metal.)
On page 56, I explain how, based on Robin Canup's collision model, Pluto and Charon had to be uniform not differentiated before collision or else the model couldn't work. Additionally they only survived a collision and remained as two separate bodies if they collided at slow speeds with a slight angle of impact keeping their temperatures primarily low enough to remain uniform. |
|
Furthermore, at most, only about 40% of Pluto heated to temperatures between 150 K and 300 K most of which was below 200 K.
That's assuming they collided which I maintain they did not.
In order to get a molten metal core this paper indicates you need temperatures around 1,800 K. Think about it, when Pluto was forming it was far from the Sun meaning collision speed's and rate's occurred relatively slowly and infrequently that's why Pluto is small (two thirds the size of our moon). It built up slowly by impacts of icy bodies with dirt, dust, salts, rock and small bits of metals.
Pluto was built, one impact at a time, one hit then maybe 50 years later another slow hit then maybe 25 years later a fast hit then 75 years later another hit and these impact rate examples are extremely frequent. Ice balls with some rocky material sometimes colliding at low velocity sometimes fast but always infrequently built Pluto. Is it then reasonable to jump to the conclusion Pluto had a molten hot metal core from these small impacts. Is it even possible these snowball impacts heated Pluto to 1,800 to 2,000 Kelvin? Robin Canup's theoretical model of two massive bodies (Pluto/Charon) impacting only heated less than half of Pluto to temperatures at most 300 K.
Instead, consider this scenario, Pluto/Charon is a ball of rock hard ICE all the way to its core with intermingled bits of stuff like nitrogen, methane, space dust, carbon monoxide, salts, silicate rock, heavy metals etc., suspended in ROCK ICE, Unless impacted by another body or tidally flexed they remain in this suspended frozen prison since things remain really cold in the Kuiper belt. The gravitational crushing force isn't strong enough to heat the core. However, when impacted, shock waves fracture the rock ice and heat pockets to low temperatures which briefly allow some localized separation. The heating by impacts would not be sufficient to allow heavier particles to separate out in significant quantities to form a hot rocky core.
Francis Nimmo says it like this, the original accretion process and small impacts would play a minor to negligible roll in contributing to differentiation. Quote from the Francis Nimmo paper
5.2 Heat Production
For the icy satellites, there are three main sources of heat: accretion, radioactive decay, and tidal heating. Even for Ganymede-size satellites, the gravitational energy released during accretion is rather modest, so that initial differentiation is not guaranteed [Barr and Canup, 2008]. (Ganymede is more than twice Pluto's size) If accretion happens sufficiently rapidly, some melting will take place [e.g., Lunine and Stevenson, 1982], but the overall contribution to the existence of present-day oceans is minor to negligible.
Pluto grew slowly enough over time to experience primarily impacts that fractured and liquefied surface ices. The energy from impacts was mostly felt on the surface as Pluto grew over time. This is not like the vision of the late heavy bombardment displayed on TV, where asteroids and comets are crashing into a body like a swarm of bees (which is a ridiculous scenario even at the Earth's distance from the Sun). This scene is one of soft and hard icy bodies impacting periodically with localized surface results while the core remains cold.
That's assuming they collided which I maintain they did not.
In order to get a molten metal core this paper indicates you need temperatures around 1,800 K. Think about it, when Pluto was forming it was far from the Sun meaning collision speed's and rate's occurred relatively slowly and infrequently that's why Pluto is small (two thirds the size of our moon). It built up slowly by impacts of icy bodies with dirt, dust, salts, rock and small bits of metals.
Pluto was built, one impact at a time, one hit then maybe 50 years later another slow hit then maybe 25 years later a fast hit then 75 years later another hit and these impact rate examples are extremely frequent. Ice balls with some rocky material sometimes colliding at low velocity sometimes fast but always infrequently built Pluto. Is it then reasonable to jump to the conclusion Pluto had a molten hot metal core from these small impacts. Is it even possible these snowball impacts heated Pluto to 1,800 to 2,000 Kelvin? Robin Canup's theoretical model of two massive bodies (Pluto/Charon) impacting only heated less than half of Pluto to temperatures at most 300 K.
Instead, consider this scenario, Pluto/Charon is a ball of rock hard ICE all the way to its core with intermingled bits of stuff like nitrogen, methane, space dust, carbon monoxide, salts, silicate rock, heavy metals etc., suspended in ROCK ICE, Unless impacted by another body or tidally flexed they remain in this suspended frozen prison since things remain really cold in the Kuiper belt. The gravitational crushing force isn't strong enough to heat the core. However, when impacted, shock waves fracture the rock ice and heat pockets to low temperatures which briefly allow some localized separation. The heating by impacts would not be sufficient to allow heavier particles to separate out in significant quantities to form a hot rocky core.
Francis Nimmo says it like this, the original accretion process and small impacts would play a minor to negligible roll in contributing to differentiation. Quote from the Francis Nimmo paper
5.2 Heat Production
For the icy satellites, there are three main sources of heat: accretion, radioactive decay, and tidal heating. Even for Ganymede-size satellites, the gravitational energy released during accretion is rather modest, so that initial differentiation is not guaranteed [Barr and Canup, 2008]. (Ganymede is more than twice Pluto's size) If accretion happens sufficiently rapidly, some melting will take place [e.g., Lunine and Stevenson, 1982], but the overall contribution to the existence of present-day oceans is minor to negligible.
Pluto grew slowly enough over time to experience primarily impacts that fractured and liquefied surface ices. The energy from impacts was mostly felt on the surface as Pluto grew over time. This is not like the vision of the late heavy bombardment displayed on TV, where asteroids and comets are crashing into a body like a swarm of bees (which is a ridiculous scenario even at the Earth's distance from the Sun). This scene is one of soft and hard icy bodies impacting periodically with localized surface results while the core remains cold.
|
Comets & Asteroids
Comets are primarily ice with space dust locked in suspension.
Asteroids are comets with their volatile ices evaporated away that became space dirt balls which in turn transformed into rocks as they neared the Sun which in turn baked off the volatile ices leaving behind the harder material, |
Asteroids are primarily located in the inner portion of the asteroid belt between Mars and Jupiter. Near the outer edge of the main belt the asteroids become somewhat comet like as their icy gasses remain frozen beyond the frost line. The inner asteroid belt is largely devoid of water ice while the outer is not. Within the asteroid belt is what's called the frost line beyond which volatile gasses freeze this line is about 2.7 AU from the Sun (1 AU = distance from Earth to Sun). Beyond 3 AU the Sun's energy is not sufficient to melt water ices.
Comets, retain a large portion of their water and loose vast plums or jets of water vapor as they pass near the Sun along their transitional phase toward becoming an asteroid. Comets typically come from the Kuiper belt or Ort cloud far away from the Sun's intense energy. The amount of time exposed to heat (and the intensity) determines the distinction between an asteroid and a comet. The Pluto/Charon system in the Kuiper belt receives little to no heat from the Sun. They remain primarily ice impregnated with space dust and their primary source of energy is from impacts or tidal flex if orbiting another body in an eccentric manner.
Comets, retain a large portion of their water and loose vast plums or jets of water vapor as they pass near the Sun along their transitional phase toward becoming an asteroid. Comets typically come from the Kuiper belt or Ort cloud far away from the Sun's intense energy. The amount of time exposed to heat (and the intensity) determines the distinction between an asteroid and a comet. The Pluto/Charon system in the Kuiper belt receives little to no heat from the Sun. They remain primarily ice impregnated with space dust and their primary source of energy is from impacts or tidal flex if orbiting another body in an eccentric manner.
|
Comet 67P
This is comet 67P Churyumov-Gerasimenko. The European Space Agency (ESA) sent a probe named Rosetta with a small lander on board called Philae to investigate 67P. This comet came from the Kuiper belt and is made of the same stuff as Pluto/Charon. Rosetta and Philae orbited and landed on 67P and collected some previously unknown information about comets.
Three of those discoveries at 67P stand out. Discovery 1. The water on 67P has 3 times the amount of deuterium as water on earth. This suggests water was not delivered to Earth by comets during the late heavy bombardment. |
Because of this 3 to 1 deuterium ratio discrepancy, scientists are suggesting water was instead delivered by asteroids. I don't think either scenario accurately portrays how water got on Earth. My theory is explained on page 75. and page 79 Deuterium is produced in our Sun and is found in large quantities on our Moon since it doesn't have an atmosphere.
Earth, however, has an atmosphere which blocks the accumulation of deuterium, 67P likely accumulated this deuterium from passing near the Sun. The fact that our earth's water is not heavily laden with deuterium indicates the object(s) that delivered water to earth didn't spend a lot of time orbiting and absorbing deuterium from the Sun since its ignition.
If multiple impacts (as in the Late Heavy Bombardment) delivered all the water to earth a significant portion would enter orbital paths around the Sun prior to impact increasing the deuterium delivered to earth.
Earth, however, has an atmosphere which blocks the accumulation of deuterium, 67P likely accumulated this deuterium from passing near the Sun. The fact that our earth's water is not heavily laden with deuterium indicates the object(s) that delivered water to earth didn't spend a lot of time orbiting and absorbing deuterium from the Sun since its ignition.
If multiple impacts (as in the Late Heavy Bombardment) delivered all the water to earth a significant portion would enter orbital paths around the Sun prior to impact increasing the deuterium delivered to earth.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA and Dr Paolo C. Fienga/LXTT/IPF for the additional process. and color.
|
Discovery 2. The dust on the surface of 67P is about 8 inches thick while the ice just below the surface is a mixture of ice and dust and is a very dense ice that is similar to rock.
This indicates a large amount of ice has sublimated out (evaporated) leaving the dust behind, 8 inches worth that's a lot of evaporated ice. This is the same ice water with embedded dust as on Pluto/Charon with the difference being a lack of heat to separate the dust out of the ice water. Eventually this dust will compress and pack itself into rock changing 67P into an asteroid if it doesn't first collide with something. |
Discovery 3. Comet 67P has no magnetic field meaning no active core and the porosity of the ice tends to increase toward the center of the comet (it gets fluffier, less dense). Meaning there is no active heat core, no rocky core and fractures in the ice increase near the center allowing for more separation of particulates which is how the center would eventually become a rocky core (my thoughts). In addition, this suggest Pluto/Charon may be less dense at their center than at their outer edges depending on gravitational compression.
Comet 67P is tiny compared to Pluto hence compression forces are vastly different. Comet 67P at 4.3 by 4.1 km (2.7 by 2.5 mi) is about a third the size of Pluto's smallest moon Styx at 13 by 8 km (8 by 5 mi). Come
Pluto/Charon likely have temperature related hard outer thick shells, since their gravitational compression force at the core isn't stronger than the rock hard ice mantle, their outer layers are more tightly compacted than the core.
Comet 67P is tiny compared to Pluto hence compression forces are vastly different. Comet 67P at 4.3 by 4.1 km (2.7 by 2.5 mi) is about a third the size of Pluto's smallest moon Styx at 13 by 8 km (8 by 5 mi). Come
Pluto/Charon likely have temperature related hard outer thick shells, since their gravitational compression force at the core isn't stronger than the rock hard ice mantle, their outer layers are more tightly compacted than the core.
|
Think of it like an Ostrich egg shell which is thick, rigid and protects the soft inner membrane from external compression forces.
An ostrich egg can withstand the weight of less than 120 kgs or 265 lbs. When impacts occur on Pluto's surface, the ice fractures settles then reforms, compressing tighter and tighter like a boa constrictor snake. |
Standing on Ostrich Eggs
|
Methane lakes on Titan
|
Gas, Liquid, Solid
Elements that we view as gasses here on earth are actually solids on Pluto because of the 35° K cold temperature. On titan, 94° K, the gas we call methane exist as a liquid and a type of rain or snow, whereas, H2O is the rocky ground. Water on earth exist as a gas, liquid and solid depending on temperature.
Most elements will also go through these three phases depending on the temperature and pressure within which they exist. |
Take steel, for example, it is a solid normally but weld two pieces together and you can see steel in all three phases, it liquefies to melt together but also vaporizes with plumes of smoke. Nitrogen on Pluto/Charon is a soft solid that can flow as a liquid given a little increase in atmospheric pressure or heat energy but is also found in Pluto's atmosphere as a gas similar to what water does on earth.
On earth the atmospheric air we breath has 78% nitrogen. The gas we breath on earth is the gas you would walk on at Sputnik Planitia. The nitrogen at SP is like a soft glacier flowing across the land with a tooth paste like consistency. When elements or compounds are at a temperature and pressure where they can exist simultaneously in all three states its called their triple point. When this triple point of temperature and pressure is altered, the compounds or elements will migrate into one or the other state. Nitrogen is seen mostly in its frozen state on Pluto but the atmosphere is also primarily nitrogen and there is evidence of fluid nitrogen in several locations indicating nitrogen's triple point temperature and pressure is straddled on Pluto.
On earth the atmospheric air we breath has 78% nitrogen. The gas we breath on earth is the gas you would walk on at Sputnik Planitia. The nitrogen at SP is like a soft glacier flowing across the land with a tooth paste like consistency. When elements or compounds are at a temperature and pressure where they can exist simultaneously in all three states its called their triple point. When this triple point of temperature and pressure is altered, the compounds or elements will migrate into one or the other state. Nitrogen is seen mostly in its frozen state on Pluto but the atmosphere is also primarily nitrogen and there is evidence of fluid nitrogen in several locations indicating nitrogen's triple point temperature and pressure is straddled on Pluto.
Mordor - One theory to rule them all
|
A Theory
|
|
This is my adjusted view based on all these observations,
A series of objects hurl through space and travel in clusters. They orbit around a central gravitational point just like Pluto and its moon's, This cluster of objects collided with Charon. Their sizes and shapes mostly matched the impacts on Charon's North pole as well as the moons Hydra, Nix, Kerberos and Styx. Previous impacts on Charon's Southwestern edge hit diagonally towards the Northeast cracking Charon along this diagonal line like an egg on a bowl. |
|
Pluto's gravitational pull also worked to distort Charon into an oval shape with the greatest stress at the equatorial zone.
It would have been sort of like sitting on a beach ball or balloon collapsing the poles while bulging the equator. |
|
The release of force would be at the area of greatest stress (girl bites balloon creating an area of greatest stress providing an immediate release of force). There must have been a fluid below the crust created by tidal flex energy as the two planets eccentically orbited each other. If Charon had a fluid layered between the outer crust and an inner mantel, this fluid would have decoupled the two layers and spilled out and onto the remaining inner mantel immediately following the southern hemisphere's fracture.
The North Pole of Charon was then impacted by a group of objects delivering a one, two, three punch breaking off large parts of the southern hemisphere.
Charon's debris acted like a shoot gun blast fired at Pluto. Much of the debris impacted Pluto on the side facing Charon. Some of the debris fell back onto Charon gently enough to preserve the large blocks on the now cooling viscous fluid. Other chunks of debris flew off into space. Some of Charon's ejected chunks missed Pluto creating moons that look more like ice rocks (with odd spins) than moons.
The fact that Nix rotates slowly backwards while Hydra rotates really fast forward may indicate these two objects glanced off opposite sides of Pluto causing opposite spins and speeds of rotation (not likely but it's fun to speculate).
Other chunks would have come close enough to Pluto/Charon to slow them into elliptical orbits. This means that there may be other moons orbiting Pluto/Charon in an elliptical pattern. When New Horizons flew by and took pictures, these elliptical orbiting moons may have been further out in space out of detection range. We probably will, some day, find at least one of these ice rocks and we will call it a moon of Pluto.
A theory proposed by scientists to explain the red stuff on Charon's north pole suggests it was transferred there from Pluto's atmosphere through a process called "Cold Trapping". I am suggesting an alternative explanation as to what put the red stuff on the north pole of Charon and additionally it explains the liquefying of the southern hemisphere while amazingly matching the general size and color of the four orbiting ice rocks or moons. and explains the impacts on Pluto facing Charon while explaining the fractures and fluid at Sputnik Planitia. One explanation ties all these seemingly unrelated events together.
I am not a scientist, these are simply my speculations about the Pluto/Charon story.
The North Pole of Charon was then impacted by a group of objects delivering a one, two, three punch breaking off large parts of the southern hemisphere.
Charon's debris acted like a shoot gun blast fired at Pluto. Much of the debris impacted Pluto on the side facing Charon. Some of the debris fell back onto Charon gently enough to preserve the large blocks on the now cooling viscous fluid. Other chunks of debris flew off into space. Some of Charon's ejected chunks missed Pluto creating moons that look more like ice rocks (with odd spins) than moons.
The fact that Nix rotates slowly backwards while Hydra rotates really fast forward may indicate these two objects glanced off opposite sides of Pluto causing opposite spins and speeds of rotation (not likely but it's fun to speculate).
Other chunks would have come close enough to Pluto/Charon to slow them into elliptical orbits. This means that there may be other moons orbiting Pluto/Charon in an elliptical pattern. When New Horizons flew by and took pictures, these elliptical orbiting moons may have been further out in space out of detection range. We probably will, some day, find at least one of these ice rocks and we will call it a moon of Pluto.
A theory proposed by scientists to explain the red stuff on Charon's north pole suggests it was transferred there from Pluto's atmosphere through a process called "Cold Trapping". I am suggesting an alternative explanation as to what put the red stuff on the north pole of Charon and additionally it explains the liquefying of the southern hemisphere while amazingly matching the general size and color of the four orbiting ice rocks or moons. and explains the impacts on Pluto facing Charon while explaining the fractures and fluid at Sputnik Planitia. One explanation ties all these seemingly unrelated events together.
I am not a scientist, these are simply my speculations about the Pluto/Charon story.
