I have created a new forum for general discussions of physics and astronomy that aren't directly related to Celestia. I did this partly because I'd like the Celestia Users forum to be a bit more focused on Celestia-related stuff. In addition, I read the astronomy discussions on this board avidly, and it's my hope that having a dedicated astronomy forum will encourage more of them. I've already moved the life on other planets polls and the 'slow light' discussion over to the new forum.
--Chris