The Tony Todd character, "Dan", mentions that he is gonna go home and watch Star Trek. Tony Todd appeared in seven episodes and one video game of Star Trek since 1990, John Billingsley starred in Star Trek: Enterprise and screenwriter Jerome Bixby wrote several episodes of the original series. Richard Riehle also guest starred in episodes of "Star Trek: The Next Generation", "Star Trek: Voyager and "Star Trek: Enterprise".
When discussing Columbus' journey John implies that there was still widespread belief that the earth was flat. In fact, since the time of the Greeks it had been relatively common (educated) knowledge that the earth was round. (Columbus' error was in underestimating the diameter of the earth and thus the distance to Asia by a westerly route. Luckily, he bumped into the Americas where he'd roughly calculated Asia was supposed to be, otherwise they'd have been lost at sea.)
It the very beginning of the movie, Edith (Ellen Crawford) notices a painting on the ground by the truck and asks about the artist. The dialogue makes it clear she saw the painted surface of the canvas but she wouldn't have been able to see it from it's angle and from where she was standing.
John Oldman: Believe in what He tried to teach without the rigmarole. Piety is not what the lessons bring to people, it's the mistakes they bring to the lessons.
John Oldman: I had a chance to sail with Columbus, only I'm not the adventurous type. I was pretty sure the earth was round, but at that point I still thought he *might* fall off an edge some place.
The Sunset Limited (2011), 12 Angry Men (1957), My Dinner With Andre (1981)For other sci-fi "What if" that treat religion and time, wihthout big effects and posing questions, check out Sound Of My Voice (2011), Pimer (2004)K-PAX (2001)