Solar System Islet

Fermi proposed a paradox as early as 1950. If a civilization arose anywhere in the galaxy, then a million years of development would be enough for it to spread to every corner of the galaxy. By that logic, Earth should have been occupied by aliens long ago.

But why have we still never seen an extraterrestrial civilization? Why can't we even find a trace of one?

When the Two-Dimensional Crisis arrived, the mystery was solved, and human civilization reached a turning point in its fate.

(A chuuni sci-fi short story I wrote a while ago.)