What’s going on with the moons of Jupiter?

The orbit of Jupiter’s moons are all messed up and seemingly overlap. Do they interact much?

Greg, U.S.

Jupiter has 67 confirmed moons. Of these, 8 are regular satellites with nice prograde motion (they move in agreement with Jupiter rotation).

The regular moons are divided between the Galilean moon (Io, Europa, Ganymede, Callisto) and the Amalthea group (Amalthea, Thebe, Metis, Adrastea). The Galilean moons formed with Jupiter while the other objects are possibly captured, and they act as ‘shepherd moons’ for the rings, keeping them stable.

The other moons are captured asteroids that were slowed down by the protolunar disk (the disk of dust and gas where Jupiter’s regular moons formed), which could absorb the momentum of the asteroid.

These objects have broke apart due to the (physical not emotional :p) stress of being captured and were hit by other passing bodies, and they are now in a complex orbital setting, as you can see below. 

But the moon are also complex inclinations, which allow them to orbit without hitting each other.

As far as we can tell, the moons have reached an equilibrium. This equilibrium might not be stable in the long run though. Mars is slowly destroying its moon Phobos, and our own Moon is slowly getting away from Earth.

Everything in the Universe is ephemeral, so we should be happy to see some consistency.. even if it’s only for now.

 

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