Topography of Chaotic Terrain on Europa Presented by: Adriana Riggs Mentor: Richard Greenberg, LPL University of Arizona

Europa One of Jupiter’s moons Size of Earth’s moon Thin layer of ice Hidden liquid water Tidal Heating What is Europa? - one of Jupiter’s moon - size of Earth’s moon: 3,100 kilometers in diameter - Human eye: white globe - Its surface is composed of ice: ~ 150 kilometers water layer - Hidden liquid water - Tidal heating: - Image: enhanced coloring and contrast shows streaks and cracks on surface. infrequent. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life.[12] Heat energy from tidal flexing ensures that the ocean remains liquid and drives geological activity.[13]

Two main kinds of terrain Tectonic Terrain Cracks Ridges Chaotic Terrain e.g. Conamara From images two main types of terrain make up Europa - Tectonic Terrain: crack and ridges - Chaotic Terrain: Conomara Choas, disrupted terrain, rafts

Two main kinds of terrain Tectonic Terrain Cracks Ridges Chaotic Terrain e.g. Conamara

Conomara Chaos - rafts, puzzle Terrain we will further explore

Melt-through model for chaos Tidal heating Thinning ice Exposed liquid Refreezes Lumpy Bumpy matrix Predicts matrix is no higher than surrounding terrain The characteristics of chaotic terrain can be explained by the melt-through model for chaos Tidal heating: Continous push and pull from Jupiter creates friction and stress on Europa core Heating various regions of the ice from below Thinning ice: Ice begins to thin, however, thicker regions may remain unmelted Exposed liquid: Soon the liquid water reaches the surface, where previous terrain moves around Refreezes: As the terrain moves around the liquid water refreezes, filling areas of the surface, and creating a lumpy matrix. Melt-through model predicts the new formed matrix is no higher than surrounding terrain How do we know that?!

Stereography to Measure Heights One type of measurement is sterography Here we have two images taken by the Galileo spacecraft in 1995 Two images are of the same 8465 7746

Stereography to Measure Heights 8465 7746

Mapping & Plotting Horizontal offset is proportional to elevation We measured offsets at over 700 points Used MATLab* to create a map *Matrix Laboratory 7746 8465

Topography and Image, Overlay Surface Topography

Conclusion Topography is consistent with melt through model Connections through the ice help make life possible on Europa

Acknowledgments Richard Greenberg, LPL, University of Arizona Barron Orr & Susan Brew, Arizona Space Grant Consortium, University of Arizona Arizona Space Grant Consortium Thank you for your time.