According to physics, how does the intensity of light from distant stars change as it travels to Earth?

Light intensity follows the inverse-square law, rapidly diminishing with distance.

The rapid decrease in the perceived brightness of light sources over distance is governed by the inverse-square law. This physical principle dictates that the intensity of light spreading out from a source decreases in proportion to the square of the distance from that source. Because stars are situated at astronomical distances—measured in light-years—the light they emit spreads out over an enormous volume of space before reaching Earth. Consequently, even intrinsically luminous stars appear significantly dimmer, often dropping below the visual threshold required for human detection against the dark background.