Moons and Icy Worlds: May 2008

Wandering Poles on Europa

A new study in the May 15th issue of Nature from NAIs Carnegie Institution of Washington Team reveals that Europas poles may not have always been located in the same place. Using images from three NASA spacecraft, Voyager, Galileo, and New Horizons, the study mapped surface features on Europa and matched them with a pattern predicted if Europa had experienced an episode of ~80 degree true polar wander. This movement of the pole and subsequent change in rotation axis is only possible if Europas outer shell is decoupled from the core by a liquid layer, so the study also reinforces evidence for the presence of an ocean on Europa.