The orbits of the Galilean moons form a perfectly-tuned triple octave, plus a slightly flat minor tenth (1:2:4:9.4). After a slight glissando, they will likely

The orbits of the Galilean moons form a perfectly-tuned triple octave, plus a slightly flat minor tenth (1:2:4:9.4). After a slight glissando, they will likely settle in a quadruple octave (1:2:4:8) and stop there, in about 1.5 Gyr. It's a cross-cutting phenomenon that the natural universe likes to self-arrange itself into chords [4] https://arxiv.org/abs/2001.01106 https://arxiv.org/abs/2001.01106 ("Long-term evolution of the Galilean satellites: the capture of Callisto into resonance") via https://en.wikipedia.org/wiki/Galilean_moons#Origin_and_evolution https://en.wikipedia.org/wiki/Galilean_moons#Origin_and_evol...