Although The Dark Knight achieved the biggest opening weekend and opening week U.S. box office performance in history, it will be difficult to knock off the all-time champ, Titanic.

 Image from 'The Dark Knight'

An article in E! Online speculates on how well The Dark Knight can be expected to do over the course of its run, concluding that the new Batman film has started out on what looks like an extremely strong performance but will probably fall well short of the overall record, $600.8 million, set by Titanic.

The reason, the article points out, is simple: staying power is the most important factor. Using Pirates of the Caribbean: Dead Man’s Chest as an example, the article shows that films that really capture the society’s imagination across many different demographic groups have slower but steadier :

As it turned out, Dead Man’s Chest went about things all wrong. The way to gross $601 million is:

  • Opener smaller than The Flintstones. (Titanic‘s $28.6 million debut is the 238th "biggest" of all time, per Box Office Mojo.)
  • Play at fewer theaters, at your peak, than Lost in Space.
  • Never, ever make more than $13.6 million in a single day.

But mostly:

  • Post your second-biggest day ($13.1 million) on your 58th day in release. (Note: It’s easier to do this if, a few days prior, you nab a record-tying 14 Oscar nominations.)
  • Instead of falling by 50 percent in your second weekend, go up by 24 percent.
  • Go up by 25 percent in your fifth weekend.
  • Don’t sell fewer than $1 million worth of tickets until…day 102.

In short, make money consistently, constantly and, above all, crazily. And do it all with movie ticket prices going for about $4.69, instead of today’s $7.08 average.

Titanic, the article notes, was number 1 at the U.S. box office for 15 weeks. The Dark Knight has a very long road to travel before it challenges that accomplishment, but it did have another record-breaking weekend last week, bringing in another $75.6 million—the largest second-weekend take in history—and passing the $300 million mark faster than any other film in history.

That makes The Dark Knight the first real cinematic challenger for Titanic‘s record as a cultural landmark, even though the film still has a long way to go to break it.