Why Phi? – the resonance of Jupiter’s Galilean moons

The resonance of three of the four Galilean moons of Jupiter is well-known. Or is it? We’re usually told there’s a 1:2:4 orbital ratio between Ganymede, Europa and Io, but while this is not far from the truth, a closer look shows something else. The three moons in question – in order from Jupiter – … Continue reading Why Phi? – the resonance of Jupiter’s Galilean moons