https://spacescoop.org/en/scoops/2609/why-does-jupiter-have-bigger-moons-than-saturn/

Hosted by our editor, Richard Drumm.

Jupiter and Saturn are the gas giants in our Solar System. Ummm… Uranus & Neptune are now called ice giants. But back to Jupiter & Saturn.

They are the largest planets, have the most moons compared to the other planets, and if that isn't cool enough, they're home to some of the largest moons in the Solar System. Saturn has 280 or more moons in total, a total that seems to be changing daily. Jupiter has over 100 known moons so far.

As for me, I don't even try to keep count any more.

Here's where things get really interesting: Jupiter has four big moons, including Ganymede, the biggest one in the whole Solar System. Jupiter's Galilean moons from closest to farthest are Io, Europa, Ganymede & Callisto.

The first 3 are in a 1:2:4 orbital resonance with Io making 4 orbits, Europa 2 and Ganymede 1. It's been calculated that Ganymede & Callisto were in a 7:3 resonance a couple million years ago but are slipping toward a 6:3 which is a nice, stable 2:1 resonance. Callisto will likely fall into that resonance in a billion and a half years making the system 1:2:4:8. Nice & stable.

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