It would depend on your software. With Animation: Master, which I use, it means applying the rendered planet to a spherical object as a decal. UV mapping would be easier I suppose, as I have to do 2 renders from each pole, and then hope they match up properly. Sometimes I cheat by just decaling a half sphere, since I rarely show the entire planet in a sequence.
Here's how it looks in action. Please right click and save to your desktop for best results (and to conserve my bandwith).
Beauty shot movieThis was done "in the camera" with a background plate of stars (probably Flaming Pear's Glitterato plug-in), a half sphere planet, and a model of the Enterrise. I didn't build the Enterprise, but I did add the spinning engine effect to it. Topping off the scene is a lightsource simulating a star. This basically a forced perspective shot, nothing was to scale.
