Why does a shadow become more fuzzy when the object that casts the shadow is further removed from the surface it casts the shadow on?

Question

Why isn’t a shadow as sharp as one can see the object?

In: Physics

Answer 1

Because light isn’t coherent through the atmosphere, it’s diffuse. It bounces off all the objects in the world and comes at us from every direction. The further the object is from the shadow, the more of this diffuse light can lighten the shadow by reflecting off the object on which the shadow is projected.