2005 Annual Science Report
University of Colorado, Boulder Reporting | JUL 2004 – JUN 2005
Untangling Europa's Evolution
Significant progress has been made toward determining the stress history of Europa’s lineaments to understand whether the satellite is in a steady-state or if its activity level has changed over time, with implications for its capability to support life. We have succeeded in modeling surface stresses on Europa from orbital (diurnal) stressing and from nonsynchronous rotation of the ice shell using gravitational potential theory. We find that potential theory significantly improves upon previous models of surface stresses on Europa, modifying previous predictions for the extents of zones of compression, extension, and strike-slip across the surface. We have found that combined diurnal and nonsynchronous stresses predict patterns that are a compelling match for the patterns of lineaments on Europa’s surface, indicating that these stress mechanisms have combined to shape the surface. We are in the process of developing and testing “graph theory” algorithms for quantitative comparison of stress orientations and styles to mapped lineaments, to constrain the temporal evolution of the surface. These results are also valuable input toward planning for the upcoming Europa Geophysical Explorer mission.