It should be pretty obvious to you that the four planets shown in the intro scene are just texture mapped spheres. The diffuse, specular, and normal maps of the brown planets came from here. These are some truly excellent texture maps which, unfortunately, are not tileable. However, I do not need them to be tileable. I cleverly rotated each planet so that the texture map seams faces away from the camera. I also used the specular map as a height map so that there is some parallax action going on as well.
For the blue planets, I found a gas giant texture map with the file name of “Gas_Giant_Stock_Texture_by_Enderion.png” here. I do not know who Enderion is, and could not find the original source of this texture map on the ‘net. I always use www.tineye.com to try and find the original creators of found art. But anyway, from the bottom of my heart, Enderion, thank you for this blue gas giant awesomeness.