DB: Yeah, the mountain is a bit dodgy. But I tried several pics for the ground, but no one fit the rest, so I kept this.
The nebulas are very bright at some places due to sunlight from behind. I added some rays too.

Some nebula tutorials:
http://www.deviantart.com/deviation/4474744/
http://www.deviantart.com/deviation/15420584/
http://www.deviantart.com/view/15593959/
http://www.deviantart.com/deviation/4758950/

EDIT: The mountain is a stock, thanks for reminding me to give a link on my DA.