This was an early project of mine. I have learned various new methods & techniques that I can use if I chose to re-do this project. I could add clouds by creating another sphere, resizing it to be slightly larger than the main one, and then applying the cloud texture and plugging it into the alpha node. One problem I encountered was creasing at both poles when subdividing the sphere object; I have since discovered an alternate way of subdividing that avoids creasing.