Hear that sound? That’s Avatar knocking on Titanic‘s door.

Over the past three days, Fox’s sci-fi blockbuster padded another $50.3 million to its total, officially making it the top entry of 2009. (Sorry, Transformers!) The movie now stands directly behind Jim Cameron’s other film on the international charts ($1.34 billion compared to $1.84 billion) and is ranked 7th on the domestic charts. (The Dark Knight sits on that list at #2 with $533,345,358.)

Of the three new entries in this weekend’s Top 10, only Daybreakers was able to crack the Top 5. The vampire movie starring Ethan Hawke and Willem Dafoe sucked in $15.1 million for a 4th place finish. Meanwhile, Leap Year - featuring Oscar nominee Amy Adams - scored just under $10 million for sixth place. Youth in Revolt, with its $6.9 million, earned a ninth place ranking.

1. Avatar, 20th Century Fox, $50,306,217 (avg. $14,701)
2. Sherlock Holmes, Warner Bros., $16,585,327 (avg. $4574)
3. Alvin and the Chipmunks: The Squeakquel, 20th Century Fox, $16,566,489 (avg. $4550)
4. Daybreakers, Lionsgate, $15,146,692 (avg. $6003)
5. It’s Complicated, Universal, $11,007,875 (avg. $3725)
6. Leap Year, Universal, $9,202,815 (avg. $3665)
7. The Blind Side, Warner Bros., $7,531,467 (avg. $2615)
8. Up in the Air, Paramount, $7,159,294 (avg. $3228)
9. Youth in Revolt, Dimension, $6,888,334 (avg. $3678)
10. The Princess and the Frog, Disney, $4,651,156 (avg. $1775)

(You can review last week’s numbers here.)