The search for life-supporting worlds in the solar system includes the Jovian moon Europa. Yes, it's an iceberg of a world, but underneath its frozen exterior lies a deep, salty ocean and a nickel-iron core. It's heated by tidal flexing, and that puts pressure on the interior ocean, sending water and salts to the surface. As things turn out, there's also evidence of ammonia-bearing compounds on the surface. All these things combine to provide a fascinating look at Europa's geology and potential as a haven for life.
