"Gravity" took flight at light speed this weekend, soaring past industry expectations as it rocketed to No. 1 at the box office. 
 
 Alfonso Cuarón's 3-D space drama launched with a robust $55.6 million, according to an estimate from distributor Warner Bros. Heading into the weekend, pre-release audience surveys indicated that the film would make no more than $45 million in its opening weekend. Meanwhile, "Runner Runner," the only other film that debuted nationwide this weekend, fell short of even the lowest projections with a disappointing $7.6-million start. 
 
 The opening weekend tally for "Gravity" — which includes the $1.4 million the picture grossed Thursday evening — marks the biggest October debut ever. Previously, 2011's "Paranormal Activity 3" held that record with its $52.6-million opening. 
 
 PHOTOS: NASA's space shuttles in film 
 
 "Gravity" was so successful largely because of how well it did in 3-D, which accounted for roughly 80% of weekend business. To put that percentage in perspective, James Cameron's "Avatar" — another movie in which the technology was highly touted — did 72% of its opening weekend business in 3-D. 
 
 That the film sold so many 3-D tickets is particularly surprising given how resistant moviegoers have been to the format this year. This past summer, it hit an all-time low when only 25% of the opening weekend crowd who went to see the family film "Turbo" were willing to pay to see the movie in 3-D. 
 
 “This gives new hope to exhibitors who have been getting nervous about 3-D,” said Dan Fellman, president of domestic distribution for Warner Bros. “But you’ve got to be careful about which movies you release in the format. One that lends itself to the format like this doesn’t come along often, but when it does, it becomes a cultural phenomenon.” 
 
 Starring Sandra Bullock and George Clooney, "Gravity" follows two astronauts trying to navigate their way back to Earth following the destruction of their space shuttle. The film has been beloved by critics, notching a 98% fresh rating on Rotten Tomatoes. And those who saw the film this weekend -- 59% of whom were over the age of 35 — enjoyed it too, assigning the movie an average grade of A-, according to market research firm CinemaScore. 
 
 PHOTOS: Hollywood Backlot moments 
 
 Bullock, 49, is having a strong year at the box office. While "Gravity" marks the biggest opening in the star's career, she also appeared in the hit comedy "The Heat" over the summer. Initially, "Gravity" was set to star Angelina Jolie and then Natalie Portman before the part was offered to Bullock. 
 
 "Gravity" was co-financed by Warner Bros. and Brett Ratner's RatPac-Dune Entertainment for $110 million, per a source close to the production. The studio declined to comment on the film's budget. 
 
 Overseas, the movie debuted in 27 countries and collected $27.4 million — about 70% of which came from 3-D sales. The picture did well in Germany and Australia but fared best in Russia, where it collected $8.1 million. The film will open in Brazil, South Korea and Mexico later this month. 
 
 "Runner Runner" cost far less to produce, but the film's poor start still gives it little chance at financial success. Financed by New Regency for $30 million and released by 20th Century Fox, the movie failed to connect with a younger audience this weekend. Roughly 70% of the film's audience was over the age of 25, and moviegoers didn't like the film, giving it an average grade of C. 
 
 Reviewers also responded negatively to the picture about a grad student (Justin Timberlake) who travels to Costa Rica to meet up with a seedy online gambling magnate (Ben Affleck). While Timberlake has done well in the music world as of late, as an actor he has struggled to find his footing. Since his supporting turn in 2011's raunchy comedy "Bad Teacher," every film he has appeared in has grossed less than its predecessor. 
 
 ALSO: 
 
 Space drama 'Gravity' to rocket to No. 1 at box office 
 
 Alfonso Cuarón and son Jonás bound by words in 'Gravity' 
 
 Alfonso Cuarón discusses 'Gravity' ahead of the film's Friday release 
 
 Follow @AmyKinLA 
 
 amy.kaufman@latimes.com 
 
 PHOTOS AND MORE PHOTOS: Faces to watch 2014 | Movies ENVELOPE: The latest awards buzz DOCUMENTARIES: 10 best of 2013, and a new crop in 2014 ||||| The Sandra Bullock-George Clooney space drama "Gravity" rocketed to the top of the box office and into industry record books during its opening weekend. 
 
 The "Gravity" premiere red carpet as seen from a reflection in an astronaut's helmet at the AMC Lincoln Square Theaters on Tuesday, Oct. 1, 2013, in New York. (Photo by Evan Agostini/Invision/AP) (Associated Press) 
 
 This image released by Starpix shows Sandra Bullock, left, and George Clooney at luncheon honoring the film "Gravity," and hosted by The Peggy Siegal Company and Warner Brothers Pictures at The Explorers... (Associated Press) 
 
 The Warner Bros. adventure debuted with $55.55 million in North American ticket sales, according to studio estimates Sunday _ the biggest October opening ever and the biggest openings for Bullock and Clooney. 
 
 "It's all good news," said Dan Fellman, Warner Bros. president of domestic distribution. 
 
 He credited director and co-writer Alfonso Cuaron, who takes viewers into orbit with a film that's set almost entirely in space and explores the challenges faced by two astronauts during a spacewalk. Cuaron's team developed equipment and technology to replicate the weightlessness of space. 
 
 "It's never been seen before, visual effects like this," Fellman said. "Just the space shots are mind-boggling. It looks like you're right there." 
 
 Last week's top movie, Sony's "Cloudy with a Chance of Meatballs 2," rolled into second place with $21.5 million. The animated sequel features the voices of Bill Hader and Anna Faris and a cast of "foodimals," like tacodiles and shrimpanzees. 
 
 R-rated fare rounds out the top six. Twentieth Century Fox's "Runner Runner," starring Ben Affleck and Justin Timberlake, opened in third place with $7.6 million. 
 
 Warner Bros.' "Prisoners," starring Hugh Jackman and Jake Gyllenhaal, crept into the fourth spot. Universal's racing tale "Rush," starring Chris Hemsworth, drove into fifth place, followed by "Don Jon," Joseph Gordon-Levitt's directorial debut about a porn addict looking for love. 
 
 "The adult drama is back, and fall is the season for the adult drama," said Paul Dergarabedian, senior media analyst for box-office tracker Rentrak. "This is when you get your more challenging films, some of the more esoteric fare, and a lot of those movies, by their nature, have to be rated R." 
 
 Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Rentrak. Final domestic figures will be released Monday. 
 
 1. "Gravity," $55.55 million. 
 
 2. "Cloudy with a Chance of Meatballs 2," $21.5 million. 
 
 3. "Runner Runner," $7.6 million. 
 
 4. "Prisoners," $5.7 million. 
 
 5. "Rush," $4.8 million. 
 
 6. "Don Jon," $4.16 million. 
 
 7. "Baggage Claim," $4.12 million. 
 
 8. "Insidious Chapter 2," $3.87 million. 
 
 9. "Pulling Strings," $2.5 million. 
 
 10. "Enough Said," $2.15 million. 
 
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 Follow AP Entertainment Writer Sandy Cohen at http://www.twitter.com/APSandy. 
 
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 Universal and Focus are owned by NBC Universal, a unit of Comcast Corp.; Sony, Columbia, Sony Screen Gems and Sony Pictures Classics are units of Sony Corp.; Paramount is owned by Viacom Inc.; Disney, Pixar and Marvel are owned by The Walt Disney Co.; Miramax is owned by Filmyard Holdings LLC; 20th Century Fox and Fox Searchlight are owned by News Corp.; Warner Bros. and New Line are units of Time Warner Inc.; MGM is owned by a group of former creditors including Highland Capital, Anchorage Advisors and Carl Icahn; Lionsgate is owned by Lions Gate Entertainment Corp.; IFC is owned by AMC Networks Inc.; Rogue is owned by Relativity Media LLC.
– Critics dubbed Alfonso Cuaron's Gravity "extraordinary," and moviegoers this weekend sealed the deal: The George Clooney-Sandra Bullock space drama soared to No. 1 at the box office, with a $55.6 million opening that set a record for an October debut. That's about $20 million more than Gravity was predicted to make, notes the LA Times; it's also an opening-weekend record for both Clooney and Bullock, adds the AP. Rounding out the top five were Cloudy With a Chance of Meatballs 2 ($21.5 million), Runner Runner ($7.6 million), Prisoners ($5.7 million), and Rush ($4.8 million).