Europa’s surface is almost too clean. In a Solar System full of impactors, an icy moon should accumulate scars for billions of years — yet Europa has very few. The simplest explanation is also the strangest: the surface we see is young, constantly rewritten by forces rising from beneath the ice.

Europa, the ice-covered moon of Jupiter, has a problem that turns out to be a clue. Almost nothing has left a lasting mark on it. In a Solar System that has been pelting its planets and moons with rock and ice for four and a half billion years, an old surface should be crowded with [...] The post Europa’s surface is almost too clean. In a Solar System full of impactors, an icy moon should accumulate scars for billions of years — yet Europa has very few. The simplest explanation is also the stran