Rebecca Rubin Film and Media Reporter Christopher Nolan’s dark historical epic “Oppenheimer” has crossed another remarkable box office milestone with $850 million in global ticket sales. The movie, starring Cillian Murphy as the so-called “father of the atomic bomb,” has generated $311 million in North America and $542.7 million internationally to date. The film continues to crush expectations, especially for a somber, R-rated biographical historical drama that unfolds largely in dreary rooms of fast-talking scientists and politicians.