The only lighting in this world comes from a diffuse point light situated at the position of the sun. The sun and background have emissive lighting to show the full color of their texture. The Earth and sun are only lit by the diffuse point lighting.
All of the celestial bodies rotate about their y axis, but at different rates. The Earth revolves around the fixed point of the sun, while the moon’s revolution around is a bit more complex since it revolves around the non-fixed position of the Earth.
Although the model can be improved, I am pretty happy with the result since I had zero experience writing shaders and have not taken math since Calculus I ten years ago. This class involved some understanding of Linear Algebra, which I was able to follow along well enough to to find success in this class.