Ten years after sailing off with $600.8 million, Titanic remains the top-grossing movie of all-time, a title which, up until The Dark Knight onslaught, hasn’t been seriously challenged.

Why?

Statistically speaking, says Jeffrey Simonoff, borrowing a famous line from screenwriter William Goldman, “Nobody knows.”

“Many people have noted if the stock market is a high-risk market, the movies is far riskier,” says Simonoff, professor of statistics at New York University’s Stern School of Business.

Huge opening weekends and great buzz certainly increase a movie’s odds of making lots and lots of money, but beyond that, Simonoff argues, it’s all guesswork.

“What Titanic had was the amazing word of mouth that just kept growing and growing,” Simonoff says. “[But] it wasn’t like after the second weekend people could say this is going to be the No. 1 movie for the next three months.”

Actually, Titanic was the No. 1 movie at the weekend box office for about three-and-a-half months, or 15 weeks, the second-longest run in the top spot after E.T., which logged 16 weeks there in 1982.

To Vicki Kunkel, author of upcoming Instant Appeal: The 8 Primal Factors That Create Blockbuster Success, movies that play on and on and on, like Titanic, are the cinematic equivalent of potato chips—one viewing is not enough.

“Titanic pretty much had all the elements that light up the endorphins on the brain,” says Kunkel. “Anything that makes us feel good is addictive.”

If all blockbuster movies contain like elements, Kunkel points out, then Titanic had all the right elements, including a love story (see: Leonardo DiCaprio’s Jack and Kate Winslet’s Rose), a self-sacrificing heroine (see: Rose spurn her rich fiancé, Billy Zane’s Cal, for poor Jack) and a clear-cut battle between good and bad (see: Jack take on Cal).

Kunkel finds a couple of these key elements, especially the conflict between good and evil, at play in The Dark Knight. She doesn’t, however, foresee another bag of potato chips. Or, more precisely, a bigger bag of potato chips.

“We relate more to real people than we do to superheroes,” Kunkel says. “And that’s when the real addictiveness happens, when we have a deep primal connection.”

Christopher Sharrett, professor of communications and film studies at Seton Hall University, thinks there could be a different kind of connection going on between the seriously dark Dark Knight and today’s moviegoers.

“It’s ripped out of the headlines,” Sharrett says. “It’s something that appeals to a cynicism of the population.”

More than that, Sharrett thinks the untimely death of Heath Ledger, so prominent in The Dark Knight as iconic villain The Joker, is the film’s X factor—the something different that, as he sees it, distinguishes the superhero-action movie from all the other recent superhero-action movies.

But does that add up to The Dark Knight moving from $400 million, its certain next stop, all the way to Titanic’s $600 million neighborhood?

“For what it’s worth,” Simonoff says, “I would certainly say it wouldn’t be surprising given the way things look like now.”

Then again, he says, it wouldn’t be surprising if it fell $100 million short.

Says Simonoff: “You can never know for sure.”