Questions about solar system dynamics etc.

[SriDharma]

Do we know of any solar systems that have planets which orbit in opposite directions but maintain the same plane?

Any solar systems with planets orbiting in different planes?

 

Do we know of any stars orbiting a galactic core in the opposite direction as the majority of stars?

 

Do we know of any planets with moon systems where any of those moons orbit in opposite directions to each other, or in different planes?

 

Thanks for any help on this.

[Klaynos]

Do we know of any solar systems that have planets which orbit in opposite directions but maintain the same plane?

Any solar systems with planets orbiting in different planes?

 

Do we know of any stars orbiting a galactic core in the opposite direction as the majority of stars?

 

Do we know of any planets with moon systems where any of those moons orbit in opposite directions to each other, or in different planes?

 

Thanks for any help on this.

 

Well IIRC we don't know much about any other solar systems really atm...

 

As for moons then yes I think so... But not 100% sure...

[Jacques]

http://en.wikipedia.org/wiki/Retrograde_orbit

Retrograde orbits

In the Solar system, most bodies orbit in a similar (direct) direction to the rotation of the Sun. All planets and most smaller bodies orbit the Sun counterclockwise as seen from a position above the Sun's north pole. The exceptions are mostly long-period and nonperiodic comets, which can have any inclination.

 

Similarly, the larger and closer moons orbit their planets in the same direction as the planets' rotation, and so are also direct. However, the gas giant planets have large numbers of small "irregular" moons in highly inclined or elliptical orbits, thought to be captured asteroids or Kuiper belt objects (or fragments thereof), and the majority of these are instead retrograde: 48 retrograde to 7 direct for Jupiter, 18 to 8 for Saturn, and 8 to 1 for Uranus. One of the largest of these is the Saturnian moon Phoebe. Neptune is somewhat different: It seems to have captured its only surviving large moon, the retrograde but otherwise regular Triton, from the Kuiper Belt. The six irregular moons beyond Triton's orbit are evenly divided between direct and retrograde; some of these may be original Neptunian moons whose orbits were disturbed by Triton's capture, rather than being captured bodies themselves.

[swansont]

And it should make sense that a majority would orbit in the same direction, with opposite orbits having large inclinations. If that didn't hold, things would quickly collide, and you'd get rid of the "offending" satellites.

[Martin]

Do we know of any solar systems that have planets which orbit in opposite directions but maintain the same plane?

 

 

Do we know of any stars orbiting a galactic core in the opposite direction as the majority of stars?

 

those are two interesting questions. We know of exoplanet systems with THREE planets as shown by the star wobbling in a complicated way. the analysis I have seen always shows the planets orbiting in the same sense.

 

it is a question of fitting data and getting the best fit, where you have the orbit parameters of all three planets to play around with. I don't know how certain we can be, perhaps one should make a modest disclaimer and say we can be MODERATELY certain that the multiplanet systems found so far orbit in the same direction, but not completely certain.

 

they may not even have tried to fit the the data with conflicting orbits.

 

================

 

I never heard of any star in Milky that was orbiting backwards.

 

It would be such an odd thing that I think I would have heard of it, if there was such a star. But I cannot give you an authoritative source.

=================

 

there is a general theory to explain the observed dominance of rotation direction----are you familiar with it?

 

you think of a spherical cloud of gas----roughly a solid BALL shape cloud---that is collapsing by its own gravity.

 

if you average all the angular momentum of all the particles of gas, there will be an angular momentum for the whole----it could be zero, but that would be strange: just by randomness of nature one would expect it to be not exactly zero----so the cloud itself already has some small intrinsic rotation

 

that will define a PLANE and a preferred direction

 

a ball-shape cloud will naturally collapse down to make a more flat-ish cloud because nothing is preventing it----while a flat-ish rotating cloud resists collapse to some extent because of its rotation.

 

as denser bodies begin to condense out of this flattened rotating cloud, they are made by random collisions of particles that share in the average rotation and the denser bodies also tend to rotate in the same direction as the cloud.

 

SO THE WAY THESE SYSTEMS FORM TENDS TO DICTATE that they should eventually consist of stuff where the vast majority is orbiting in the same sense.

 

and then, once you have planets (or stars in the galaxy case) they can continue to interact gravitationally and also to collide with each other on rare occasions, and that probably increases the conformity of direction

 

but I think the main explanation is the dynamics of a cloud that is collapsing by its own gravity (and has some random average rotation just by randomness)

[SriDharma]

hmm, very nice, thanks everyone. Some good things to think about.

It's interesting how orbiting bodies on a macro scale like solar systems and galaxies conform to a system of balanced planes and directions. While orbiting bodies on a micro scale like atoms / electrons are (I believe) completely chaos.

[Martin]

hmm, very nice, thanks everyone. Some good things to think about.

It's interesting how orbiting bodies on a macro scale like solar systems and galaxies conform to a system of balanced planes and directions. While orbiting bodies on a micro scale like atoms / electrons are (I believe) completely chaos.

 

the atoms are going to be different because they didnt condense out of big clouds of gas and dust, like the astro systems did.

and electrons do not actually "orbit"

that is a human analogy which we humans applied to atoms because we earlier learned about the solar system, where things do orbit

 

but for atoms it really is not a very good analogy.

atoms is more like the sloshing of water in a bucket

the electron "sloshes" around the nucleus, in one of several possible wave patterns.

 

and if the atom has several, then they can each slosh around in their own wavepattern without interfering

 

there are some beautiful computer graphics of this, and also I think some nice animations---but I don't remember how to find them

[grifter]

hmm, electrons "orbiting" a nucleus, this is a common misconception, (I'm going off the point here...) we have to think of electrons in an atom as a "cloud" in fact, it is commonly referred to as a probability cloud, which put simply denotes that electrons are "smeared" around the nucleus. which leads to other fascinating properties of electrons, but thats for another article