With James Cameron‘s Avatar now the #1 film four weekends in a row ($46 million projected earnings by Sunday night) and the second-highest worldwide grosser of all time at the worldwide box office, can it overtake Cameron’s Titanic tally of $1.8 billion, and thereby become the all-time #1 earner?

It can do this if it gathers another $600 million worldwide starting Monday morning. By Sunday night Avatar will have earned $1.2 billion and change in only four weekends of play, or three and a half 7-day weeks (Friday, 12.18 to Sunday, 1.10). At this rate another $600 million doesn’t seem too hard.

It’ll take a little longer, of course, due to diminished post-holiday revenues and the fact that the first and second wavers have already seen it. But there’s a repeat-viewing factor at work plus an understanding that Avatar is not something to wait for on DVD.

I’m figuring Avatar will take Titanic by…what, February 1st? Mid-Feburary?

Avatar‘s domestic cume through last Wednesday was $374.4 million with a foreign tally of $760.9 million. It’s expected to pull in $100 million globally this weekend ($46 million here plus another $55-something over there) for a Sunday-night worldwide total of $1.235 billion, give or take. So to pass $1.8 billion it needs another $600 million.