I'm generally pretty good with figuring out lighting but I realise now that I don't fully understand how reflected light works, specifically in the included picture.

I get that the cylinder is mildly reflecting light coming off of the surface it's standing on in that example, but how come there is a dark core-shadow? Does this have to do with the angle of the form relative to the light source? Like, since the core-shadow is perpendicular to the direction of the light, is that why it's the darkest (for some reason)? Or does that reflected light have to do with the position of the spectator relative to the sphere?

If I'm not being clear enough I will try to dig out some more specific examples. Thanks a lot in advance.