Stability of the Solar System 2:1 orbit/orbit resonance. This particular resonance has important consequences because Europa's gravity perturbs the orbit of Io. As Io moves closer to Jupiter and then further away in the course of an orbit, it experiences significant tidal stresses resulting in active volcanoes. Europa is also in a 2:1 resonance with the next satellite Ganymede. The planet Mercury is especially susceptible to Jupiter's influence because of a small celestial coincidence: Mercury's perihelion, the point where it gets closest to the Sun, precesses at a rate of about 1.5 degrees every 1000 years, and Jupiter's perihelion precesses only a little slower. At
The Ganymede Club The Ganymede Club The Ganymede Club is a science fiction novel by American writer Charles Sheffield, published in 1995. A mystery and a thriller, the story unravels in the same universe that Sheffield imagined in "Cold as Ice". Shortly after humanity begins colonisation of the solar system, a trade war sets off vicious civil war that kills billions. The book received favorable reviews from "Library Journal" and "Kirkus Reviews", as well as in the science-fiction press. It was ranked #14 in SF novels in the 1996 "Locus" awards. The novel has been translated into Italian and was published as "Memoria