quadruple occultation surgery

I was so fascinated to be able to witness Io pass over Jupiter the other day, and tonight all the moons again were lined up on one side of the planet, that I started wondering: Is there ever a time when ALL the moons disappear from the sides, either because they are all behind or ahead, or a mixture of both? And if so, is there a clock somewhere that will tell us the dates and times? This is something I'd REALLY like to see.

Jess Tauber

Jess,

I have heard that it never occurs that all four Galilean moons disappear at the same time. This is because the orbital periods of the inner three are in some kind of resonance caused by their gravity. Perhaps someone knows the ratios of the orbital periods, but the ratios do not permit them to all disappear simultaneously.

Rick