Neptune, Triton, and Tidal Friction

10:09 PM 4/10/2009

Uranus and Neptune, the two most distant planets in our Solar System

Neptune is the eighth planet from the sun. It is roughly the same size as Uranus,which is the seventh planet from the Sun. They are almost identical in chemical makeup, with few differences between the two planets. Neptune is slightly more massive than Uranus, however. Neptune is much further away from the sun than is Uranus, and so recieves much less energy from the sun, than does Uranus.

Both planets are large and gaseous, made mostly of Hydrogen, Helium, Methane and Ammonia.  Their atmosphere’s are very thick and very deep. This allows them to well insulate any heat in their cores.

There are two more significant differences. Uranus is a rather strange planet in that it lies on its side relative to its orbital plane such that its poles will face the sun for half its orbital period…thus Uranus which takes some 84 years to orbit the sun will spend half that time facing the sun in the North pole, and the other half facing the sun from the south pole, though there will be a period where there will be an equinox of equal day and night at the equator as it transitions from one season to the other. Put it another way, if you lived on Uranus, and were an inhabitant of its equatorial region you would experience two seasons basically, one where the sun was directly over head and it was very warm, and the other when the Sun was very low down on the horizon, and it was brutally cold. However, you would experience this twice a year where the Sun would be low on the southern horizon for half the time, and high on the Northern horizon the other half of the cold season, with two intermittent warm seasons in between, where the Sun was high in the sky. Note the Neptunian year is roughly equal to 164 Earth years. Neptune’s revolution over its own axis is a remarkable 16 hours! Thus its day is much shorter than our own, if not quite as short as Jupiter’s which is about ten hours! For two planets so large this is a remarkable rotation and is sure to cause some unusual effects. Uranus too has a similar day with a length of seventeen Earth hours.

For our purposes here however, it is more important to note that Uranus’ rotation around it’s axis is at a right angle to the Sun’s own rotation around its own axis. Thus the Sun’s rotation would have less effect on the orbital velocity of Uranus, than it would for a planet like Neptune whose revolution is contrary to that of the Sun. There is therefore less gravitational force to accelerate Uranus’ orbit. For this reason we must presume far less friction is generated than would have been if the Sun and Uranus were experiencing coplanar revolutions where Uranus would then be expected to sustain an occipital force ejecting it from its orbit, as does Mercury for example, or even the Earth’s own Moon. Though it should be said that Uranus, being nearer to the Sun is actually travelling faster around the Sun than is Neptune. But this excess speed of Uranus is probably not significant for our purpose here.

Triton

There is yet another difference which is noticeable immediately and is very important. Though both planets have many small moons orbiting them it is Neptune that has one large moon orbiting it. It’s large moon being Triton. This sattellite is approximately one quarter the size of our own moon but is closer to Neptune than is our own moon to Earth. Triton is approximately 200000 miles away from Neptune, where our moon is 243000 miles away. Another salient fact is that Triton orbits Neptune at a much higher velocity than our own moon…that is it takes only five days to orbit Neptune whereas our own moon requires twenty eight days to orbit the Earth. Thus Triton covers approximately eighty percent of the Moon’s orbital circumfrence in a fifth of the time. There is also an increase in the acceleration towards the central body, Neptune, due to the smaller circumfrence. Thus it is that the smaller the orbital circumfrence, the greater will be the Tidal action upon the orbiting bodies. Because of this there is a higher tidal force upon Neptune from Triton than there is upon Earth from the Moon.

The most important difference is that Triton’s orbit around Neptune is Retrograde. This is to say that Triton orbits in the opposite direction of Neptune’s own revolution around its axis. Triton is also tidally locked with Neptune, keeping one face always towards the tyrant planet. The retrograde motion is extremely significant because this means that Neptune’s gravitational force is actually slowing down Triton’s orbit around Neptune as well as its own revolution around its own axis. Thus Triton is collapsing towards Neptune and will one day be crushed by Neptune and ultimately collapse unto the planet itself in bits and pieces. Because of the retrograde motion many astronomers assume that Triton was captured by Neptune from the nearby Kuiper belt, which is a distant asteroid belt just beyond Neptune from which it is assumed that some asteroids are occaissionaly dislodged and sent towards the inner planets, including our own, and which on some unfortunate times will result in large impacts on our own planet. This unusual motion and the enormous orbital speed and consequent retrograde revolution of Triton seems to me to indicate a most violent capture resulting in the release of large amounts of energy and heat in the form of friction which the planet and the moon may still retain to some degree on top of the already large amount of heat and friction that is being released in the continuing degeneration of Triton’s orbit around its master planet, Neptune.

Neptune and Triton have hot cores

It is noteworthy to realize that Triton itself has the coldest surface temperature of any moon in the Solar System. This is very significant. Because it is so far away Triton receives very little sunlight and so is an icy dead world. Or is it? It has been discovered recently that Triton is actually volcanic! In other words below its surface there is excessive heat! A very strange discovery. Here is a relatively small moon in the distant reaches of the solar system emitting heat from its core just like our own Earth! The question is why?

Neptune has some sort of anomaly very similar to Triton’s in that it too emits heat from its core that is so intense that it actually causes storms to form in its atmosphere! This is amazing. Neptune, at an average distance of 2.8 billion miles from the sun is the most distant planet in the Solar System and yet it emits heat from its core! More amazing is that when compared with Uranus, which is almost a twin of Neptune, it is seen that Neptune has a far more dynamic atmosphere and emits far more heat than Uranus. Why? If anything it is Uranus which should be hotter because it is closer to the Sun. Yet Uranus is a relatively cold planet. In fact it is the coldest of the gas giant planets! A very strange anomaly. In fact one of the strangest!

Here are the facts again! Uranus, though closer to the Sun lies on its side. The Sun’s tidal action on Uranus is minimal since for most of its time time Uranus is only pointing one pole towards the Sun. Thus the gravitational force upon the poles is minimal for most of its obit in that only a small area of the planet is facing the Sun’s direct gravitational force! Thus the tidal action on Uranus from the sun is likely   less than it might be for Neptune which has its full side facing the Sun as it revolves around its axis.

The biggest single difference,however,  between the two planets is their companions which orbit around them. Whereas Uranus has no large moons to tug on it, Neptune has Triton which causes enormous Tidal forces on Neptune due to both its size and the speed at which it is revolving around Neptune. Moreover, as we mentioned above it is nearer to Neptune than is our own moon and it circles the planet in one fifth the time.

However, what is almost certain to be the most important of all factors is that Triton circles Neptune in a retrograde orbit. A retrograde orbit causes far more friction on the opposing bodies than does a prograde orbit(if they were circling the same direction of the Neptune’s revolution about its axis.) By moving to the opposite direction Triton is causing a far larger Tidal friction on Neptune than is the Moon on Earth for example, especially due to the enormous mass of Neptune compared with the Earth, and the fact that Triton is moving so much faster in the opposite direction of Neptune’s revolution.

Degeneration of Triton’s Orbit Causes Orbital Acceleration. 

Moreover, there is an additional reason for the possible heat difference. The fact is that Triton’s orbit has been degenerating due to the retrograde motion about the planet. Thus as the planet’s orbit degenerates the large moon is falling toward the planet and getting nearer to it; but this has the effect of accelerating the planet towards Neptune,thus the moon loses orbital altitude,but obtains orbital velocity and angular momentum about its planet. Therefore the tidal energy on the planet actually increases instead of decreasing.

As important is that this orbital degeneration has probably been going on for some time and so the build up of heat within the planet has been occurring for quite some time. The same of course goes for the build up of heat within Triton which again would explain why the moon is so hot though it is so far away from the Sun.

Tidal Friction between Neptune and Triton causes heating of the Cores. Core heat affects climate of Neptune

As Triton moves in a retrograde orbit around Neptune it will slow the revolution of Neptune around its own axis. This decrease in angular momentum must release energy and it is this energy which is being captured by Neptune and so forming the storms that we see; this loss of revolutionary momentum is also the most likely cause of Triton’s volcanism. Since Neptune receives so little energy from the Sun, it is easy to postulate the possibility that the atmospheric storms of Neptune are being powered by the heat in its core, especially since voyager measured Neptune’s heat emission as one of the highest in the solar system…thus we are postulating that the climate of Neptune is in some significant manner affected by the core temperature  of the planet.

Differential Rotation of various Layers may add heat to the core.

We presume the  same is true of Earth… that the core heat of the Earth affects our planet’s climate as well, and is most likely a very significant cause of climactic variations over the Earth’s history. Though the Moon’s orbital drag on the Earth is responsible for most of the heat generated in the core of the Earth, there is also another probable cause due to a differential rotation in the deeper layers of the core from the layers nearer to the surface. At least this would be very likely to be the case on the gaseous planets since their cores are probably quasi solid compared with their surface layers. But being that the Earth’s core is quasi solid as well, and that its upper layers are also probably rigid to some degree this argument may be hard to justify. But due to the Moon’s tug on the surface layers of the planet being stronger than it is on the core(to simple action at a distance due to gravity) there a gradient in inertia which will develop. But there is also the fact that the deeper core layers of any planet will most likely be more massive and thus have more inherent inertia! If at some point in time there is significant difference in rigidity between successive layers of a planet’s core components a perpetual slippage may occur. The net effect of billions of years of differential slippage may well result in a kind of twisting of the Earth’s layers and thus store a great deal of potential energy and heat within these tensions which may be released with Earthquake activity, or Tectonic plate motion, Volcanism, and Epochal Climatic Dynamism where the climate of the Earth may be affected for thousands and hundreds of thousands of years. This same phenomenon would be active on the giant gaseous planets as well, as they too would experience differential rotations of various layers. This differential rotation has been documented and  backed by the study of certain seismic waves generated during earthquakes on Earth. However, it seems very natural that there would be such a differential rotation due primarily to the Moon’s tug of the surface layers with unequal force throughout the whole body of the Earth. Thus points closer to the Moon would be elongated and slowed due to the Moon’s gravity, and due to the differential inertia of the various layers(as we must presume that the deeper layers of the Earth are in fact more massive thus have more inertia and so are less likely to be pulled by the Moon.) Others may have the opportunity to put this proposition into a calculus, but for my purposes, I rest on the pure of the logic of the assertion, noting that all calculi rest, in the end, on the underlying assumptions and deductions of the  principles upon which they are based.

Core Heat May  Build For Epochs

Often geologists will assert that a planet has been cooling off from its primordial state for billions of years, as the Earth is supposed by geologists to be doing even now. But what is little mentioned is that tidal friction may well store heat within the core of planets for eons of time before it can escape. Thus it may be that as the Moon has revolved around the Earth for billions of years, it may have stored heat within the core of the planet that has yet to escape. Thus the planet’s core may well be experiencing the cumulative effects of this heating. The same is likely true of Neptune and Triton. They may both have stored a great deal of heat that has been insulated for eons. There is too the possibility that little is understood of the actual dynamics of thermodynamic production of Tidal heat deep within the cores of planets. The truth is that we have little understanding of the makeup of planets deep within their cores, and we have little real knowledge of the behavior of matter under the enormous pressures experienced in the cores of planets and large moons. So it is not really fair to say that our present theories of thermal energy due to Tidal action is well understood that we might be certain we understand the total energy output of such tidal action. For example, if the cores of planets are actually rotating at different speeds from the surface layers, we would not have good working models of heat generation due to tidal action.

 We do not now have good mathematical models of core heating due to Tidal action

We cannot assume that we fully understand the action of tidal forces on highly pressurized matter which may well be in plasma form at the core of planets. There is simply not enough experimental evidence to come to any firm conclusion about the adequacy of tidal action as a complete explanation or lack thereof,of the heat emanating from the core of planets. Yet when we take all the circumstantial evidence around Neptune, there is almost no question that tidal forces are the real cause of the excess heat on Neptune. There are few theories that could easily explain such a vast difference between Uranus and Neptune other than these obvious differences in their orbital interactions with their moons.

 The Kuiper Belt

There is one more difference that may add to Neptune’s excess core heat. It may be that Neptune experiences tidal action from the many bodies around the Kuiper belt as well. Apparently Neptune interacts with many of the bodies in the belt developing enharmonic relations with them…that is to say they will orbit around the sun in proportional relationships to Neptune…thus for example a small body may orbit around the Sun twice to every three times that Neptune orbits, or perhaps once to every two times that Neptune orbits the Sun. These relationships are caused by gravitational interactions between the bodies and Neptune. Being that there are so many such bodies in the Kuiper belt,there is little doubt that this results in significant tidal friction when all is taken together.

There is also a more direct orbital relationship with some of these bodies. It turns out that Neptune is in a one to one orbit with a number of bodies in the Kuiper belt. That is to say that Neptune and these bodies orbit at the same period around the Sun, or stated another way, each time that Neptune orbits around the Sun, so does one of its Trojans. This is the name given for these bodies with this special relationship. There are a number of these bodies with such a relation to Neptune’s orbit. Though there are a few theories which tend to dismiss a direct capture by Neptune of these bodies, there is almost no precedent for this kind of relationship and I am inclined to believe that these bodies were in fact captured by Neptune and that Neptune’s gravitational force is keeping these bodies in synchronous orbit around the Sun. This would also indicate that there may well be gravitational tidal forces from these bodies as well as they are themselves nudged and tugged by other bodies in the belt which forces would also tug on Neptune somewhat.

It is possible that these Trojans form a kind of Gravitational structure which feeds off its own energy and as it picks up objects from the belt may well be gaining inertia! In any case, depending on how large this structure may be(there may well be many such bodies within the belt constituting a significant shadowy other for Neptune’s gravitational relations)this structure will cause some Tidal tugging which would result in the release of some heat from the planet. All of these facts taken together make a good case for the causes of the atmospheric differences between Uranus and Neptune. There is a lot more reason to suppose that gravitional interactions are the cause of the excess heat emanating from Neptune than it would be to assume that one planet is merely taking longer to cool off from its primordial state than the other. Even if that theory is given its due as being significant, we can still not explain why one such planet is so much cooler than the other being that they are the same size and probably formed during the same time except that one planet was subjected to excessive tidal forces and the other not.

This still leaves Triton! Triton’s internal heat could not be explained any other way than by Tidal heat and so the Hot Core Earth hypothesis would explain this phenomenon as well. If Triton had an atmosphere there is little doubt that it would capture that heat and it too would have storms and atmospheric episodes. Atmospheres are very likely a key component in the capturing of that volcanic heat that probably emanates from all large bodies in the solar system. If a body has an atmosphere then it is likely to have a climate no matter how far away from the central star it may be(especially if it is in a highly energetic orbit)…needless to say this theory, if ultimately true, would have tremendous implications on Astro-Biology. We are left to conclude that Neptune’s active weather pattern is not caused by the Sun, but by it’s core heat, and this is being caused most likely by the interaction of Neptune with its moons and with Triton in particular. There is also contributing heating taking place from the Sun’s own tidal interaction with Neptune(absent to a large extent on Uranus) as well as the Tidal interactions experienced by Neptune through the Kuiper belt gravitational relationships.

The Neptune-Triton relation supports the Earth-Moon core warming hypothesis

The Neptune-Triton relation and the abnormal heating experienced by the two bodies  goes a long way in suggesting that Earth’s own climate is not merely caused by the Sun’s heating as has for so long been assumed, but also by the core heat being generated by the Moon’s orbit around the Earth, as well as what tidal heat is generated by the Earth’s orbit around the Sun. It is far more reasonable to presume that large scale climatological changes on the Earth, including the Snowball Earth phenomenon in which the Earth was covered by ice some seven hundred million years ago was likely caused by core heating and variations which were perhaps temporarily exhausted due to some prolonged geological activity resulting in the release of heat which then led to the consequent colder surface temperatures on the surface of the planet as the core heat was exhausted from the upper layers of the Earth’s subsurface.  At the very least, we must come to suspect that some kind of core interaction must have played a significant role in the phenomenon and in all long period climatic phenomena that affect the Earth’s surface. We are fairly certain that Volcanic energy likely ended the period of global icing, and this too may have been due to the insulation caused by the ice blanket around the earth; this is the same principle that warms an iglue which is insulated by the ice and thus heat is allowed to build up inside the structure.  This same principle to some degree or other facilitates large build ups of heat in the cores of all planets with large satellites around them over long periods of time that ultimately affect their surface temperature, especially if they have substantial atmospheres.

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