No matter what particles i add, the particles just won't receive light.
They're just black blobs. Anywhere else those blobs would be blue.

In picture 2: A normal scene in which the particle cloud is illuminated with the exact same type of point light that is placed in the Solar System scene.
Shadows and lighting work perfectly fine on it.

If I import this same cloud in that other scene, the cloud will no longer be illuminated. Maybe I should delete the original point light there and add a new one.

I've deleted the original light in the Solar scene... The results on the cloud were terrible. Just look at the cloud in picture 3. It's no longer fuzzy, it looks like a freaking opaque mesh.