Sun's equator being 7 degrees to the ecliptic

[dougettinger]

What is the most current explanation for the Sun's equator being inclined 7 degrees to the ecliptic plane ? And Jupiter, the biggest constituent of angular momentum in the solar system is inclined about 6 degrees to the Sun's equator. Saturn is inclined about 4.5 degrees to the Sun's equator.

Is not this fact a big challenge to the Nebular Hypothesis ?

Doug Ettinger
Pittsburgh, PA

[bystander]

Since the ecliptic is relative to the Earth's orbit, it is not a good standard for angular momentum. Rather than saying the Sun's equator is inclined 7° to the ecliptic, it's probably more appropriate to say the Earth's orbit is inclined 7° to the Sun's equator (the largest inclination of all planets). The best measure with regard to angular momentum is the inclination to the invariable plane. Jupiter is inclined only 0.32° to the invariable plane. Uranus has the largest inclination of the gas giants at 1.02°. The Sun's equatorial plane is inclined 5.6° to the invariable plane (or you could say the Sun's axial tilt is 5.6°).

[wonderboy]

Damn RJN he's just changed the way I speak. I was reading this and pronounced Uranus You RAN us. I was old school before and liked the giggle, I'm a changed man .

As for the suns equator and whatsit, I have no idea, I'll keep up and see if I learn something.

Paul

[Chris Peterson]

Since the ecliptic is relative to the Earth's orbit, it is not a good standard for angular momentum. Rather than saying the Sun's equator is inclined 7° to the ecliptic, it's probably more appropriate to say the Earth's orbit is inclined 7° to the Sun's equator (the largest inclination of all planets). The best measure with regard to angular momentum is the inclination to the invariable plane. Jupiter is inclined only 0.32° to the invariable plane. Uranus has the largest inclination of the gas giants at 1.02°. The Sun's equatorial plane is inclined 5.6° to the invariable plane (or you could say the Sun's axial tilt is 5.6°).

Well put. I'll add something about the causes of the various small deviations from a single plane. Early in the formation of the Solar System, the high density of the condensation zone would have produced effects that tended to flatten orbits, and to circularize them. But those effects largely disappeared once the planets formed and the system was swept of most remaining material. This all happened in just a few million years, so it isn't surprising that the flattening and circularizing mechanisms did not finish. We were left with planets which are not quite coplanar, and not quite in circular orbits. Give things more time, in a denser medium, and you get different results. Saturn's rings are a great example of just how flat, and how circular an orbital system can get.

[dougettinger]

Damn RJN he's just changed the way I speak. I was reading this and pronounced Uranus You RAN us. I was old school before and liked the giggle, I'm a changed man .

As for the suns equator and whatsit, I have no idea, I'll keep up and see if I learn something.

Paul

Human beings are rather big and complicated places, too.

DBE

[neufer]

Saturn's rings are a great example of just how flat, and how circular an orbital system can get.

It should be noted that Saturn and all the gas giants maintain very flat equatorial
ring systems primarily because of a strong quadrupole gravitational force field.

At the present time the sun generates an imperceptible quadrupole gravitational force field.

[dougettinger]

Is a quadrupole a May pole with four ropes? I am just kidding, Neufer. OK. What is a quadrupole gravitational force field ?

Doug Ettinger
Pittsburgh, PA

[neufer]

OK. What is a quadrupole gravitational force field ?

Saturn spins so fast that it takes the shape of an oblate spheroid.

This shape distorts the radial gravitational field in a very specific way
much like as the four fold EM force fields below:

[wonderboy]

Is a quadrupole a May pole with four ropes? I am just kidding, Neufer. OK. What is a quadrupole gravitational force field ?

Doug Ettinger
Pittsburgh, PA

It is a gravitational forcefield, of which there are four of course...... Silly






Paul

[dougettinger]

OK. What is a quadrupole gravitational force field ?

Saturn spins so fast that it takes the shape of an oblate spheroid.

This shape distorts the radial gravitational field in a very specific way
much like as the four fold EM force fields below:

I was not aware that the space probes discovered this phenomena. This quadrupole force field is very interesting. So how are four distinct gravity force fields created inside Saturn that are being compared with magnetic moments ? Are there any present hypotheses?

Doug Ettinger
Pittsburgh, PA

[dougettinger]

The Sun's equatorial plane is inclined 5.6 degrees to the invariable plane. Are there any hypothetical reasons for this occurrence inside or outside the nebular hypothesis ?

Doug Ettinger
Pittsburgh, PA

[Chris Peterson]

It should be noted that Saturn and all the gas giants maintain very flat equatorial ring systems primarily because of a strong quadrupole gravitational force field.

I don't believe that is true. The primary reason that rotating systems become very flat is because of inelastic collisions between particles. Essentially, the more the rotating medium behaves like a viscous fluid dynamics model, the flatter it gets. I'm willing to believe that the structure of the gravitational field is a factor, but not the primary one.

[Chris Peterson]

The Sun's equatorial plane is inclined 5.6 degrees to the invariable plane. Are there any hypothetical reasons for this occurrence inside or outside the nebular hypothesis ?

Just my suggestion- I haven't read anything about the matter. Once the nebula condenses sufficiently that fluid dynamics stops being an important factor, the orbital and rotational planes are largely established. That is likely to occur before everything becomes perfectly coplanar. Then you have another billion years or so of significant perturbations, with planetary orbit positions changing considerably, and lots of opportunities for angular momentum exchange. So some things get flatter, some get more oblique, and some things get jettisoned from the system completely.

[dougettinger]

It should be noted that Saturn and all the gas giants maintain very flat equatorial ring systems primarily because of a strong quadrupole gravitational force field.

I don't believe that is true. The primary reason that rotating systems become very flat is because of inelastic collisions between particles. Essentially, the more the rotating medium behaves like a viscous fluid dynamics model, the flatter it gets. I'm willing to believe that the structure of the gravitational field is a factor, but not the primary one.

Eventually outer rings, especially Saturn's, evaporate or dissipate, are absorbed by larger bodies, or fall into the planet over millions of years. A remember a question being posed that it is a mystery how the rings remain replenished over the age of the solar system. The Nice Theory's process could have been a source for the rings in the remote past, but what has replenished the rings in the near past ?

Doug Ettinger
Pittsburgh, PA

[dougettinger]

The Sun's equatorial plane is inclined 5.6 degrees to the invariable plane. Are there any hypothetical reasons for this occurrence inside or outside the nebular hypothesis ?

Just my suggestion- I haven't read anything about the matter. Once the nebula condenses sufficiently that fluid dynamics stops being an important factor, the orbital and rotational planes are largely established. That is likely to occur before everything becomes perfectly coplanar. Then you have another billion years or so of significant perturbations, with planetary orbit positions changing considerably, and lots of opportunities for angular momentum exchange. So some things get flatter, some get more oblique, and some things get jettisoned from the system completely.

I understand your excellent explanation why small deviations from a single plane occurred in the solar system. But this explanation still does not answer why the Sun's equatorial plane is radically different from the invariable plane defined by averaging the angular momentum of the complete system. Your present answer would suggest that the Sun was perturbed itself or the entire invariable plane was perturbed which is difficult to conceive. Perhaps I have discovered an unanswerable anomaly or arrived at the edge of understanding in the nebular hypothesis.

Doug Ettinger
Pittsburgh, PA

[Chris Peterson]

Eventually outer rings, especially Saturn's, evaporate or dissipate, are absorbed by larger bodies, or fall into the planet over millions of years. A remember a question being posed that it is a mystery how the rings remain replenished over the age of the solar system. The Nice Theory's process could have been a source for the rings in the remote past, but what has replenished the rings in the near past?

There is strong, but not conclusive evidence that Saturn's ring system is not primordial, but is on the order of 500 Myr old. The most difficult aspect of this theory is that the formation of the ring system would have required the disruption of a body about the size of Mimas, which is statistically unlikely to have occurred in that time period. Of course, the difference between a 4.5 Gyr age and a 500 Myr age completely changes the question of ring sustainability.

It is estimated that the ring system absorbs its own mass in meteoroids in 4.5 Gyr. So there is superficially enough mass to sustain the rings for a long time. As it happens, models based on this mechanism do a good job predicting the observed albedo and color structures seen in the rings.

All that aside, the question of the formation and evolution of Saturn's rings remains a very active area of research. Cassini is providing a wealth of information that is rapidly driving ideas. I guess we're not more than a few years away from having a very good idea how and when the rings formed.

[Chris Peterson]

I understand your excellent explanation why small deviations from a single plane occurred in the solar system. But this explanation still does not answer why the Sun's equatorial plane is radically different from the invariable plane defined by averaging the angular momentum of the complete system. Your present answer would suggest that the Sun was perturbed itself or the entire invariable plane was perturbed which is difficult to conceive. Perhaps I have discovered an unanswerable anomaly or arrived at the edge of understanding in the nebular hypothesis.

I'm not sure I'd consider a 6° angle between the Sun's equatorial plane and the Solar System's invariant plane to be "radical". It seems entirely plausible that early in the formation of the Solar System one or more Jupiter mass objects were ejected. That would be sufficient to explain a shift in the invariable plane with respect to the Sun's equator. We have no way of knowing (for now, at least) what actually occurred, but it doesn't seem to require any particularly unlikely or unphysical cause.

Obviously something got perturbed. I don't think this runs up against the nebular hypothesis. I'd expect every system to be unique, based on its individual history. The nebular hypothesis is just a framework describing a general mechanism for stellar system formation; end results are likely to be highly variable.

[dougettinger]

Thank you for your very thoughtful reply. I very much like your very plausible ejection of one or more Jupiter mass objects. I am very impressed with the quickness of the angler pulling this answer out of his fishnet. It probably means that there are a lot of ejected Jupiters and assorted rocks and ice balls traveling in interstellar space. I am hoping the space in front of the Sun's trajectory is quite vacant.

Doug Ettinger
Pittsburgh, PA

[Chris Peterson]

Thank you for your very thoughtful reply. I very much like your very plausible ejection of one or more Jupiter mass objects. I am very impressed with the quickness of the angler pulling this answer out of his fishnet. It probably means that there are a lot of ejected Jupiters and assorted rocks and ice balls traveling in interstellar space. I am hoping the space in front of the Sun's trajectory is quite vacant.

I doubt we are at much risk. I am reminded of one of my favorite quotes of Douglas Adams:

"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

[neufer]

I'm not sure I'd consider a 6° angle between the Sun's equatorial plane and the Solar System's invariant plane to be "radical". It seems entirely plausible that early in the formation of the Solar System one or more Jupiter mass objects were ejected. That would be sufficient to explain a shift in the invariable plane with respect to the Sun's equator. We have no way of knowing (for now, at least) what actually occurred, but it doesn't seem to require any particularly unlikely or unphysical cause.

Obviously something got perturbed. I don't think this runs up against the nebular hypothesis. I'd expect every system to be unique, based on its individual history. The nebular hypothesis is just a framework describing a general mechanism for stellar system formation; end results are likely to be highly variable.

The early sun dissipated a great deal of angular momentum by (dare I say it) electromagnetic means; there is no reason to believe that what little angular momentum was left was pointing in the exact same direction as where it started from.

<<After its birth some 4.6 billion years ago, the Sun had an extremely active magnetic field during its infancy, with gigantic dark star- or Sun-spots that sometimes covered its polar regions. Indeed, sometime after the tenuous gas of the Solar nebula began collapsing into the proto-Sun within its host molecular cloud, a strong magnetic field developed that was instrumental in transporting rotational energy away from its core region in bi-polar jets of gas so that centrifugal forces created by the nebula's collapse did not grow so much as to halt continuing gravitational contraction. Before Sol finished forming, around a tenth of the gas and dust around it may have been ejected by infalling through its accretion disk and then being blown out by bi-polar jets to produce two giant lobes of molecular gas, and bow shocks from the jets hitting the surrounding stellar nebula. Known as Herbig-Haro objects since their discovery in the early 1950s, these lobes typically extend a few light-years in length, have masses similar or larger than the developing star itself, and are moving apart at speeds of tens to a few hundred kilometers (several to tens of miles) per second. Stretching for several light-years, such bi-polar jets may be driven at supersonic speeds by an intense magnetic field at the axis of rotation of an embryonic star less than a few hundred million years old.

The gas and dust moving outward carried angular momentum away from the developing Sun and allowed accretion to continue, but also churned up the surrounding nebula and so provided the necessary turbulence to slow down its collapse. Eventually, the supply of infalling matter ran out and shut down Sol's bi-polar jets. Subsequently, much of the surrounding gas and dust that remained around Sol was blown away, by the young star's radiation in T-Tauri winds after core nuclear fusion was turned on. >>

[bystander]

I am reminded of one of my favorite quotes of Douglas Adams:

"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

I am reminded of Dan Quayle:

Space is almost infinite. As a matter of fact, we think it is infinite.

[neufer]

Douglas Adams: "Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

Dan Quayle: Space is almost infinite. As a matter of fact, we think it is infinite.

• Charles Lamb: "Nothing puzzles me more than time and space,
  . and yet nothing puzzles me less, for I never think about them."
  -------------------------------------------
  __ Finnegans Wake: Page 419
  
  My in risible universe youdly haud find
  Sulch oxtrabeeforeness meat soveal behind.
  Your feats end enormous, your volumes immense,
  (May the Graces I hoped for sing your Ondtship song sense!),
  Your genus its worldwide, your spacest sublime!
  But, Holy Saltmartin, why can't you beat time?

[BMAONE23]

Even the Moon has a fair inclination difference WRT the Earth.

[neufer]

Even the Moon has a fair inclination difference WRT the Earth.

Our moon is a special case of a collision induced satellite.