Can a Planet Have Multiple Moons with Unique Orbital Patterns?

  • Context: Stargazing 
  • Thread starter Thread starter Lymsleia
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Discussion Overview

The discussion explores the possibility of a planet having multiple moons with unique orbital patterns, including crossing orbits, parallel orbits, and shared orbits. It addresses theoretical aspects of moon orbits in relation to a planet's rotation and gravitational dynamics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions if a planet can have two moons orbiting in crossing patterns, one around the equator and another around the poles.
  • Another participant asks if multiple moons can orbit in parallel patterns, such as one around the equator and others in the northern and southern hemispheres.
  • A further inquiry is made about whether two moons can share the same orbit but be positioned directly opposite each other.
  • Some participants affirm that moons can share orbits but caution that such configurations may lead to collisions.
  • It is noted that orbits are determined around the center of mass of the system, typically the planet, which is assumed to be much larger than the moons.
  • One participant mentions that the direction of a planet's rotation does not necessarily affect the orbiting moons, depending on their formation and capture dynamics.
  • Another participant highlights that the stability of certain orbital configurations is contingent on the masses of the moons involved, indicating that large moons cannot maintain unstable orbits.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the feasibility of various orbital configurations for moons. Some points remain contested, particularly concerning the stability of orbits and the influence of a planet's rotation.

Contextual Notes

Participants reference gravitational dynamics and the center of mass in their discussions, but there are unresolved assumptions regarding the masses of the moons and the specific conditions under which these orbits could exist.

Lymsleia
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hello,
i can't seem to find answer in my country forum, so I ask here, hope you don't mind

-----------
(1)
Is it possible for planet to have 2 moon orbit in crossing pattern?
like... one orbit around equator another orbit around north and south pole(2)
Can multiple moon orbit in parallel pattern?
like... one orbit around equator, one orbit around northern hemisphere, and another orbit around southern hemisphere.

(3)
Can 2 moon share same orbit but directly opposite to each other?

--------------
thank you in advance for the answer.
oh and... English is not my native language, forgive me if I'm wrong in spelling or grammar.
 
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(1) yes - be careful so they don't collide
(2) no - orbits are around center of mass of system, usually center of planet (assumed much larger than moon)
(3) yes
 
so, I presume that planet direction of rotation have nothing to do with orbiting?
 
Lymsleia said:
so, I presume that planet direction of rotation have nothing to do with orbiting?

That depends. As this Wikipedia entry explains: "If formed in the gravity-field of a planet as the planet is forming, a moon will orbit the planet in the same direction as the planet is rotating and is a regular moon. If an object is formed elsewhere and later captured into orbit by a planet's gravity, it can be captured into a retrograde or prograde orbit depending on whether it first approaches the side of the planet that is rotating towards or away from it. This is an irregular moon."
https://en.wikipedia.org/wiki/Retrograde_and_prograde_motion
 
mathman said:
(1) yes - be careful so they don't collide
(2) no - orbits are around center of mass of system, usually center of planet (assumed much larger than moon)
(3) yes
However, it should be noted that both 1 and 3 are unstable orbits, unless both orbiting bodies have negligibly small masses. That is, you can't have large moons in these configurations.
 

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