I had the idea for this after watching an episode of Stargate Universe. I really like the effect they have of the.. I'll just call it space wash, that flows over the ships force field. It reminded me of the cloud vapor that flows over an airplane. So my brain got working on how I could achieve such an effect, but first I needed something for the effect to flow over. I decided I'd go with a mixture of an asteroid and comet.
I ended up with about four files with different particle settings. All of which were layered over the asteroid, and some were blurred to give the gaseous effect. Originally there was just a stationary spinning rock with the particles flowing over it, but while in After Effects I decided to add the BG and FG elements to give the viewer the feeling that they were riding in some kind of ship alongside the rock.