Unfortunately not easily. They aren't actual 3d objects, so they can't rotate in other directions.
Haha, yeah it was a little above my math level too:-) They are great though!! It really looks great in my game, I'm making a 2D sidescroller with pixelart style in space. These planets and asteroids are really cool for the background! I took the shaders which Hiromitsu Matsubara converted to Unity and added the black hole and universe because they were not in there. Then I added scripts so that they can be used on sprites and all settings can be changed. So now I use them as shaders in my game instead of exporting the spritesheets. I also created a particle effect that spawns asteroids of random sizes and rotate them over time randomly. It looks really great!!! If you want I can put the sources for that on Github after I've finished my game, just say the word:-)