What are the real life factors of light attenuation. Say in normal atmospheric conditions.
There’s haze, but the primary reason for point sources is that as light radiates, it disperses – the same energy is flowing through a larger area.
For point light in void (clear air is almost like void), the lighting is l=L/(r*r) with L being the color/intensity of the light and r the distance to the light. Think about the surface of a sphere centered on the light.