New research published in the Geophysical Research Letters has found that Europa’s poles have shifted, and the cracks show that the icy surface has reoriented by 70 degrees. This event occurred fairly recently in the last few million years. 

This “true polar wander” can only happen if the icy shell is disconnected from the moon’s core and is free-floating on a subsurface ocean, which is a great confirmation of the composition of Europa.

Lead author Paul Schenk explains: Our key finding is that the fractures associated with true polar wander on Europa cross-cut all terrains. This means that the true polar wander event is very young and that the ice shell and all features formed on it have moved more than 70° of latitude from where they first formed. If true, then the entire recorded history of tectonics on Europa should be reevaluated.

The research was done using images from NASA’s Galileo spacecraft, and the results give us several questions that the upcoming Europa Clipper mission should be able to answer.

More Information

Lunar and Planetary Institute press release 

“A Very Young Age for True Polar Wander on Europa from Related Fracturing,” P. Schenk, I. Matsuyama & F. Nimmo, 2020 July 29, Geophysical Research Letters