Which Way Do Planets in Our Galaxy Spin?

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    Galaxy Planets Spin
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Discussion Overview

The discussion revolves around the direction of planetary motion in relation to their stars within the galaxy, specifically whether all planets in various solar systems spin or orbit in the same direction. It encompasses concepts of planetary spin, orbital mechanics, and angular momentum, with references to both our solar system and exoplanetary systems.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question whether all planets in the galaxy spin in the same direction, noting that within our solar system, not all planets do, with Venus exhibiting retrograde spin and Uranus having a tilted spin axis.
  • One participant clarifies that their interest lies in the orbital paths of planets around stars rather than their spin, suggesting a potential link between the motion of galactic arms and planetary orbits.
  • Another participant states that the orbital planes of different star systems are oriented randomly, implying that planets do not all orbit in the same direction.
  • Angular momentum conservation is mentioned in relation to the question of planetary motion, though the implications of this are not fully explored.
  • A later reply discusses the concept of three-dimensional rotation being non-orientable, indicating that the designation of clockwise or anti-clockwise is observer-dependent.

Areas of Agreement / Disagreement

Participants generally agree that within our solar system, planets have consistent orbital directions, but there is no consensus on the behavior of planets in other star systems, with multiple competing views on the randomness of their orbital orientations.

Contextual Notes

The discussion highlights limitations in knowledge regarding the spin and orbital characteristics of exoplanets, as well as the dependence on the observer's perspective when discussing rotation.

Canada Bob
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TL;DR
Is the spin the same ?
Do all the planets in all the solar systems in our Galaxy spin in the same direction ?
Clockwise or anti clockwise depending on the viewers POV.
 
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Canada Bob said:
Do all the planets in all the solar systems in our Galaxy spin in the same direction ?
We don't know the spin of any planets outside our solar system, but we do know that even just within our solar system, not all planets spin in the same direction. Venus's spin is retrograde, and Uranus's spin axis is tilted on its side (i.e., close to the plane of its orbit).
 
Moderator's note: Thread moved to Astronomy forum.
 
PeterDonis said:
We don't know the spin of any planets outside our solar system, but we do know that even just within our solar system, not all planets spin in the same direction. Venus's spin is retrograde, and Uranus's spin axis is tilted on its side (i.e., close to the plane of its orbit).
Thanks for the above Peter, apprecited, maybe I should rephrase my question, it's the path around the sun or any other star that I meant to ask about, rather than the spin of the planet itself.

If depending on the POV all the planets in our solar system follow a clockwise path around the sun, would all the planets in our galazy follow clockwise paths around their stars ?

I'm wondering if the motion of arms of stars swirling around our galaxy dictates the path of planets around their stars ?
 
The orbital planes of different star systems are oriented essentially randomly, so no they don't all orbit in the same direction.
 
Canada Bob said:
If depending on the POV all the planets in our solar system follow a clockwise path around the sun, would all the planets in our galazy follow clockwise paths around their stars ?
Angular momentum is conserved, if that's your question.
 
Canada Bob said:
it's the path around the sun or any other star that I meant to ask about
Ah, got it. In our solar system, all of the orbits of the planets are roughly in the same plane (though not exactly) and in the same direction. However, as others have noted, the planes of different stellar systems are oriented randomly (at least as far as we know), so it would not make sense to say that planets of other stars orbit in the same direction as planets in our solar system do.
 
What's more than that, three-dimensional rotation is non-orientable. That is, it is artificial to say that it is clockwise or anti-clockwise. It depends completely on the position of the observer.

In spaces with an even number of dimensions, rotation is orientable. Such is the case with quantum spin.
 

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