In my early days of using Photoshop (back in version 7.0, before Creative Cloud, before Creative Suite!) I enjoyed the challenge of making pieces of art from scratch. Among my favorites were creating planets and other science fiction landscapes. Here are some other tests but this time in After Effects.
AE recipe
Planet Texture: Fractal Noise, Colorama, Curves
Planet: CC Sphere, Curves, Glow
Atmosphere: Circle, Ramp, Fast Blur, Fractal Noise, Curves
Stars: Fractal Noise, Fast Blur, Levels
Sun: Lens Flare, Fast Blur, Noise, Curves, Fractal Noise
Composite to taste and season as desired.