Europa is one of the solar system’s greatest puzzles. Orbiting Jupiter every 3.5 days at a distance of 670,900 km, this icy moon conceals what scientists believe is a vast, subsurface liquid ocean.

Ever since the Voyager flybys in 1979 and the Galileo mission in 1995 provided our first close-ups of Europa’s chaotic landscape, scientists have been working to plan the ultimate follow-up mission: penetrating the surface to sample the ocean below. Doing so requires knowing exactly how thick the outer crust is.

While standard planetary models assume a crust composed purely of ice, Brown University researcher Christine McCarthy discovered that salt fundamentally alters the equation.

“Scientists make models to estimate the crustal thickness, but they assume that this crust is composed of just ice,” states Christine McCarthy, student/research assistant at Brown University. “We’ve discovered through our experiments that, for certain kinds of salt (we’re trying all the salts that are suggested by the spectra), the combination of ice and salt is a lot stronger than just the ice alone. That should change everyone’s estimations of how thick the crust would be.”

To turn raw experimental data into publishable insights, Christine relied on KaleidaGraph. “I use Double-Y scatter plots to show the true strain and the stress plotted against time for my creep experiments. I mask out a nice linear region of the strain plot and curve fit to obtain the steady-state strain rate. Finally, I plot the stress and strain rate points on a log-log plot.”

Christine went on to present her findings using KaleidaGraph plots at both the American Geophysical Union and the Lunar and Planetary Science Conference. For more details on Christine’s research, visit: http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2512.pdf