Titanic Film Theory: Jack Is A Time Traveller!?

To know the answer to this, we need only examine what difference Jack being on the Titanic may have made made. Luckily for us, the film shows us just what a big difference Jack’s presence made to a certain Rose DeWitt Bukater.

The first time Jack and Rose meet, Rose is hanging off the end of the Titanic, about to commit suicide by plunging into the icy depths of the Atlantic ocean. Fortunately for Rose, Jack’s brutally honest description of the plunge is enough to convince Rose return from the rails and make her way back onto the ship, at which point he saves her from a fall when she slips. As well as saving her life literally, Jack also saves her life in a more psychological sense, reminding her that her life is worth living, and bringing her back from the brink of suicidal despair into a woman who lives a long and happy life.

Jack's guardian angel role back in the past is also supported by the fact that, prior to saving Rose, Jack is just hanging out on the ship deck in the middle of the night doing nothing. It's almost as if he was waiting for her to show up. Bare in mind that this is the middle of an April night somewhere in the middle of the Atlantic ocean. It’s got to be damn close to 0C (if not below) on deck at this time. Hardly the weather for stargazing, unless you had to be there for some reason.

So we can reasonably assume based on Jack’s actions that his intention back in the past was to save Rose, but this leads to the further question of... why?

Rose is an incredibly beautiful lady for sure, but was a steamy session in the backseat of an old-timey car worth a potentially suicidal jump back in time? Just why did Jack go back to save Rose?