Io's escape

Abstract

According to the latest study, our witnessing of the volcanic splendour of Jupiter's moon Io might just be a lucky circumstance. The odds are that the satellite will become quiescent on its escape from orbital custody. The extreme geological activity that makes Jupiter's moon Io the most volcanically active body in the Solar System is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Making use of astrometic observations made between 1891 and 2007, Lainey et al. have estimated the tidal dissipation in Io by tracking its effect on the orbital motions of the Galilean moons. For Io the value is in good agreement with the observed surface heat flow and suggests that Io is close to thermal equilibrium. Dissipation in Jupiter is close to the upper bound of its average value expected from the long-term evolution of the system.