ASTRONOMY COLLOQUIUM - APRIL 11, 2006

Christopher Chyba, Princeton University

New Constraints on Europa's Ocean

We will quickly review the evidence for Europa's liquid water ocean, then discuss new empirical constraints on the ocean's salinity and those constraints' implications for the thickness of the europan ice shell. Galileo spacecraft magnetometer data combined with gravity data and simple interior models appear to require that the ice shell be thin, and the ocean extremely saline. If there is time, some astrobiological implications will be discussed.