Celestia

[davekill]

For us astronomy and sci-fi geeks.
A 3D space simulator that is truly amazing and educational.
I found it here: http://sourceforge.net/projects/celestia/

The best part is it's free and available in three versions - PC, Mac, and Linux to keep you occupied for many winter days ahead.

But that's not all...
The fun starts when you customize your Universe with all the add ons or 'addons' found online. I'm still exploring the Celetia Motherlode collection:
http://www.celestiamotherlode.net

Lots of Trek ships and planets
2001, Avatar, Babylon 5, Ringworld, Silent Running, Star Wars and SG1 too.
Haven't found anything from Dune yet.

The add-ons are the work of the fan base.
Countless talented contributers who create textured 3D geometry in the form of fictional and historical pieces for the rest of us to geek-out on :)

CMOD is the native file format for Celestia, but most are saved in 3DS which can be opened in nearly any 3D application. I found that Max or Poser works best to truly appreciate the pieces.
Below are a couple of the add-ons. I opened and rendered the Omega Class ship in 'Poser'.

There are plenty of youtube videos to review but they are nothing compared to actually using Celestia

[Bromptonboy]

looks intriguing.