For space geeks: [link]
European spaceflight controllers are now making their final communications with the Huygens probe, soon to be deployed on the last leg of its journey to Titan. Once it separates from the Cassini mother ship at 10:08 PM ET on Dec. 24, they will never be able to speak to it again. And even when (or if) they again hear its voice, it will only be an echo after it has already died.