One of the most complicated shader types in cg are the earth shaders. Although there are only a few 3d spheres with textured surfaces and one sunlight you have to choose unlimited opportunities to design a performant, realistic and detailed scene of the earth, the moon and the sun. There are many different techniques and material properties to design an earth surface model – realistic or abstract. I’ve created a photorealistic earth & moon shader for V-Ray Renderer based on the NASA Blue Marble Earth Maps. You can download this models here.

http://www.turbosquid.com/3d-models/planet-earth-photorealistic-3d-max/683041