The starfield and nebulae were made using a clip which can be found here: http://forums.planetside.co.uk/index.php?topic=2017.0 .
I used a very dense atmosphere, which explains why everything blurs out near the edges of the planet.
Phew... if that isn't intimidating, I don't know what is ;). Very nice! The lava looks quite realistic, and the way the planet itself is rendered with the soft edges at the side also adds to the realism, too. My only complaint is that the borders of the lava oceans are a bit unrealistic.
Nice one. 8)