Celestia - Space simulation software

http://www.shatters.net/celestia/

Celestia is "free space simulation that lets you explore our universe in three dimensions."

Celestia lets you explore space across a huge range of scales, from galaxy clusters down to spacecraft only a few meters across. A 'point-and-goto' interface makes it simple to navigate through the universe to the object you want to visit.

It runs on Windows, Linux, and Mac OS X.

To find out more, visit http://www.shatters.net/celestia/

To download click http://www.shatters.net/celestia/download.html

Screenshots