ABCNews -- When actor James Dean died in a car wreck in 1955, studio executives wrung their hands and moaned "there goes the movie," believing audiences would be scared away from seeing the two films he'd completed shooting just before his death. In today's darkly cynical, celebrity-obsessed culture, Wes Gehring, a film professor at Ball State University in Indiana and author of a book on Dean, believes it's highly doubtful that anyone at Warner Bros. would ever have said such a thing about "The Dark Knight," after Heath Ledger, who portrays a disturbingly deranged Joker, died in January from an accidental prescription drug overdose. "We are a much more cynically humorous world," Gehring told ABCNews.com. "A tragedy happens and it's on the Internet...