Yahoo News has some more information about The Pioneer Anomaly that czar posted about a couple of months ago. Basically, the Pioneer 10 and 11 spacecraft have inexplicably slowed down due to unknown forces. Conventional physics states that the spacecraft should continue at a constant velocity and course unless acted on by an external force. The latest study on the Pioneer Anomaly attempts to figure out what this external force might be, with no definitive answer just yet.
