Cosmological question for you science wizards

I've noticed that member jiggerj asks many intriguing cosmological questions, and his threads are always chock-full of answers. You can learn a lot from a jiggerj thread. I was watching Star Trek earlier when I started getting nagged by a cosmic inquiry of my own.

Most of us know the why and wherefore of how the solar system was formed and about planet rotation etc.

All the planets in our solar system revolve around the sun in the same direction. However, not every planet rotates in the same direction.

The planets all revolve around the sun in the same direction and in virtually the same plane. In addition, they all rotate in the same general direction, with the exceptions of Venus and Uranus. These differences are believed to stem from collisions that occurred late in the planets' formation.

www.scientificamerican.com...

My question: Is it possible for a planet or satellite to revolve in a reverse direction? What kind of event would it take to cause this? Are there any known examples?

But that also makes me wonder...do all satellites in every solar system revolve and/or rotate the same way? For example, does every satellite revolve clockwise/counter-clockwise in relation to its star? Does solar system A and solar systems B,C,D etc. all show revolution in the same direction?

Thanks in advance for any answers. I look forward to learning!

Well, Venus spins the opposite direction of all the other planets in the solar system but still revolves around its star the same direction. So, here is a case of something spinning against its original rotation. I am not sure if this falls in the category you are asking for though. As for why it happened, there are theories, but science does not know for sure.

Given when we search for other solar systems, the only indication we have of planets is a brief dimming of their sun, its impossible to answer that question about other star systems.

reply to post by TheSparrowSings


No, I'm talking about revolution, not rotation. Is it possible, even theoretically, that there is a solar system out there where one or two rebellious satellites or planets are revolving in opposite directions. That's what I'm wondering.

Thanks.

Originally posted by NarcolepticBuddha
reply to post by TheSparrowSings

 

No, I'm talking about revolution, not rotation. Is it possible, even theoretically, that there is a solar system out there where one or two rebellious satellites or planets are revolving in opposite directions. That's what I'm wondering.

Thanks.

edit on 9-6-2013 by NarcolepticBuddha because: (no reason given)

yes, it's completely possible.

There's probably even solar systems with planets in perpendicular planes.

Originally posted by Ghost375

Originally posted by NarcolepticBuddha
reply to post by TheSparrowSings

 

No, I'm talking about revolution, not rotation. Is it possible, even theoretically, that there is a solar system out there where one or two rebellious satellites or planets are revolving in opposite directions. That's what I'm wondering.

Thanks.

edit on 9-6-2013 by NarcolepticBuddha because: (no reason given)

yes, it's completely possible.

Are there known examples? What events cause this? Can you cite evidence that makes you conclude this? Details, please!

en.wikipedia.org...

Retrograde motion is motion in the direction opposite to the movement of something else, and is the contrary of direct or prograde motion. This motion can be the orbit of one body about another body or about some other point, or the rotation of a single body about its axis, or other phenomena such as precession or nutation of the axis. In reference to celestial systems, retrograde motion usually means motion which is contrary to the rotation of the primary, that is, the object which forms the system's hub. In the Solar System, all the planets and almost all of the other objects that revolve in orbit around the Sun, with the exception of many comets, do so in the "prograde" direction, i.e the same sense as the rotation of the Sun. Most planets also rotate in the same prograde direction, the exceptions being Venus and Uranus, which have retrograde rotations. Most satellites of planets also revolve around their planets in the prograde sense. (In the case of the satellites of Uranus, this means they revolve in the same sense as Uranus's rotation, which is retrograde relative to the Sun.) There are some satellites which revolve in the retrograde sense, but these are generally small and distant from their planets, except for Neptune's satellite Triton, which is large and close. It is thought that these retrograde satellites, including Triton, are bodies which have been captured into orbit around their planets, having been formed elsewhere.

This is very possible and already been proven in alien planets observed lately. Google it and I am sure you will find something. I am obsessed with the universe and absolutely love learning more about it.

All the planets with the exception of Venus and Uranus have direct and prograde motion. Uranus is a weird one that rather than it being retrograde it is actually rolling around with a 90degree axis tilt.. which is quite strange.

This was possibly caused by a large impact by a rogue object early in formation (but that is really just a theory with little provable evidence) There is also a moon of Neptune that has retrograde motion (Triton). Evidence is that this moon was captured by neptune... this evidence is mainly in total mass of the moons (other than Triton) which is tiny, Triton dwarfs the rest, which is odd as moons forming in a gas cloud would be expected to follow a relatively organized mass pattern... The other is the inclination of the orbit.

Anyway it is not 100% known how all these retrograde objects form, as due to conservation of angular momentum you would expect all gas coalescing around a star during its early life to have relative angular momentum. There could however be the possibility of tidal locking or resonance that caused the gas cloud to be more chaotic around venus... or it was victim of an early collision that took much of its orbital momentum. The rotation of venus is extremely slow, slowest of all planets

Weird, I was reading about this not too long ago.

There is some evidence that solar systems can form from more than one cloud of condensing matter.
There could be a main protoplanetary disk, and a second one that counter-rotates in relation to the first.
The conclusion is that planetary bodies could form out of each disk.
Therefore, eventually there could be two families of planets in that system. A set from each cloud of counter-rotating matter.

From NRAO

In the case of a young star some 500 light-years from Earth in the direction of the constellation Ophiuchus, Remijan and Hollis found the inner and outer parts of the disk rotating in opposite directions.

"We think this system may have gotten material from two clouds instead of one, and the two were rotating in opposite directions," Remijan said. There is sufficient material to form planets from both parts of the disk, he added. The object is in a large, star-forming region where chaotic motions and eddies in the gas and dust result in smaller cloudlets that can rotate in different directions.

In the above case, planets would begin their lives revolving in that certain direction. Some one way, some the other.

I think the fact that there is evidence of counter-revolving planet formation. Answers your other question about if Solar systems always have the same direction of revolution..Seems like that would not be the case.

Planets carry the momentum of the primordial dust cloud so they are generally all together. Retrogrades are thought to be rare but they have been observed. (see link at the bottom)

Planets can start on a retrograde orbit by interacting with other planets. For example a small planet can have a close encounter with a large planet like Jupiter. and get going the other way.

Very early in the dust cloud coalescence there can be small bodies that get in retrograde orbits and continue to pick up material. Farther along during the solar system evolution there are planets in eccentric orbits and these have more chance of getting it retrograde orbits.

www.space.com...