When Mitch rides the cart into the steam tunnels, the viewer briefly sees the quotation, "Against stupidity the gods themselves contend in vain" scrawled on the left wall. These are the original words of the German poet Friedrich Schiller. Relevant to the film, Isaac Asimov named three separate stories "Against Stupidity", "The Gods Themselves" and "Contend in Vain". He later combined them into a 1972 science fiction novel about a conspiracy by aliens who inhabit a parallel universe with different physical laws than ours, and who are trying to turn our Sun into a supernova in order to collect the resulting energy for their use.