Fog only working on light sources?

Hello everyone! I'm going to preface this question by saying I am EXTREMELY NEW to both game development and Unity. I have been a programmer in other languages for years, but just recently decided to try my hand at game development so if the answer is obvious, please be gentle. :)

I have an outer space scene with stars/suns that are point light sources with a basic texture. Around each are planets, which are just untextured spheres at this moment. When I apply fog, the suns behave as expected with the furthest away being completely obscured while the closer they get, they brighter they get. However, the planets seem to be unaffected by the fog. They show up no matter how far away they are. Is this just a setting I missed somewhere or does it have to do with them not be textured? Or maybe something else all together?

Thanks in advance for anyone that can help me out!

EDIT: Attached screenshot. You can see at the "farthest" distance, there isn't a sun to be seen, but you can still see the planets/spheres just fine, albeit small.