Another Nice Story:
Once upon a time:
And everyone lived happy ever after.
- The 4 giant planets formed in mean motion resonances with one another. (Morbidelli et al.)
- Jupiter and Saturn were in the 2:3 MMR, which stops migration.
- Natural result of planet/disk interactions.
- All within 12AU of the Sun! Unstable but for the resonances.
- Beyond them was a massive disk that extended to ~30AU.
- Contained objects ~ size of Pluto, which stirred the disk.
- The 4 giant planets pushed inward due to viscous stirring in this disk.
- This pushes the planets out of their mutual resonances orbits go boom!
- Uranus and Neptune are scattered into the disk.
- Uranus and Neptune evolve onto current orbits due to interactions with the disk.