Scientific Colloquium
April 9, 2013
3:45 p.m
NOTE SPECIAL DAY AND TIME
CO-SPONSORED BY THE ASTROPHYSICS SCIENCE
DIVISION COLLOQUIUM
CAROLYN
PORCO
SPACE SCIENCE INSTITUTE
"The Active South Polar Terrain of Enceladus: How Its
Jets, Heat and Tidal Stresses Are Related"
In 2005, the Cassini mission
at Saturn discovered a remarkable and unique geological province
at the south pole of the small moon, Enceladus. Towering jets of
powder-sized icy particles, and water vapor laced with organic
compounds, vent from several prominent fractures crossing the
500-km wide south polar cap. And a shocking 16GW of thermal
radiation emitted by the region, among other lines of evidence,
points to a regional sea below the south polar terrain, almost
certainly created by the dissipation of tidal energy arising
from a 2:1 orbital resonance between Enceladus and its sister
moon, Dione. With excess heat, organics, and liquid water, the
significance of this moon as a possible host of prebiotic
chemistry, or even extraterrestrial organisms, is obvious.
This presentation will examine the relationships between the
jets, anomalous heat, and tidal stresses, and evaluate what
these relationships mean for the mechanisms responsible for
Enceladus' surprising activity.