No one has any doubt that Oblivion, starring Tom Cruise, will have a big opening at the box office this weekend. How big? is another question. The film opened overseas last week with an impressive $60.4 million in ticket sales. No one figures it will do that well here -- but it has no competition from any other film debuting wide this weekend, and while last weekend's winner, the Jackie Robinson biopic 42, is only expected to drop 25-35 percent, its total gross last weekend was $27.5 million. The Los Angeles Times is predicting the movie will wind up with around $37 million. the Hollywood Reporter and Variety figure it will earn around $30 million. (That's what Universal is also predicting.) TheWrap.com estimates that it will earn around $35 million. Box Office Mojo's Ray Subers thinks it will take in $36.9 million. Once again the pundits are predicting that the film will perform more strongly overseas than it will domestically. All are agreed that it will cross the $100-million mark in its second weekend without difficulty.