Note that the radiance along a ray traveling through fog is no longer invariant! Which is why this slide https://cs184.eecs.berkeley.edu/sp20/lecture/11-32/radiometry-and-photometry specifically mentions the radiance being invariant through a vacuum (and I suppose mostly invariant through air).
Unreal Engine 4 uses volumetric fog to create natural god rays. It looks similar to the image described above, but artists are able to mimic the sharp cut of light through the sky by using the same concept of participating media. Here's a link to a tutorial: https://www.youtube.com/watch?v=Akb4P71KL0s