Enceladus, the tiny Saturnian satellite, regularly issues jets of salty water from its south pole that reaches kilometres in height above the moon's surface. But what drives this process? Gravitational tidal forces caused by an eccentric orbit, it seems. Cornell scientist Matt Hedman has analysed where in the Enceladus orbit the plumes are most pronounced. Here he explains what was unknown about the phenomenon and what his new analysis, published in Nature, has revealed...