Movies
Symmetrical book stacking. Just like the Philadelphia mass turbulence of 1947.
— Ray · Ghostbusters

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker identifies symmetrical book stacking and links it to an oddly specific event in Philadelphia. The precise date gives the comparison an air of authority without explaining it. The humour lies in treating a strange arrangement of books as a recognizable technical phenomenon.
Context reviewed