As Alfonso Cuaron’s “Gravity” enters its second weekend of sold-out multiplexes across the country, it’s becoming the cinematic event of the year. The space epic may not break the same box office records that “Titanic” did in 1997, but in some ways it’s just as important to the movie business. “Gravity,” which arrives at a time when TV is considered more groundbreaking than movies, recaptured the water cooler buzz from “Breaking Bad,” “Game of Thrones” and “Scandal.”

But “Gravity” isn’t just a celebration of the movies — it’s also a celebration of Sandra Bullock, who has reinvented herself as a formidable dramatic actress. It’s still months before the Academy Awards, but “Gravity” will propel its star into the frontrunner seat of the Best Actress race. Here are five reasons why.

1. Like her co-star George Clooney, Bullock is an old-fashioned movie star. Her win for 2010’s “The Blind Side” came out of left field: she wasn’t in a typical Oscar-bait movie, she had never been nominated, and she defeated the great Meryl Streep channeling Julia Child. The fact that Streep took home the award a year later for “The Iron Lady” meant that voters felt guilty she lost for “Julie & Julia,” but not so guilty they wanted to vote against Bullock. Given how much she’s universally loved by the industry, Bullock could easily win again.

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2. Bullock is now the most bankable actress in Hollywood, period. Since 2009, she’s had four films with a domestic box office gross of more than $100 million (“The Proposal,” “The Blind Side,” “The Heat” and “Gravity,” which I’m including, because it will cross the mark over the weekend). That’s almost unprecedented — Channing Tatum had more blockbusters, but he also released more films. In the same time frame, Brad Pitt and Johnny Depp each had three hits of that scope (including animated movies), Natalie Portman and Angelina Jolie had two, Tom Cruise had one, Meryl Streep had one and Julia Roberts only had one.

3. Her performance represents the future. The Academy has been understandably nervous about awarding movies that suggest technology could replace actors on the bigscreen. In 2010, the year Bullock won for “The Blind Side,” “Avatar,” the biggest hit of all time, lost to “The Hurt Locker,” and Andy Serkis was not nominated for his motion capture turns in “The Lord of the Rings” or “Rise of the Planet of the Apes.” But “Gravity” is different because of Bullock. If the Academy honors her, they will be acknowledging that whatever change comes to Hollywood, there will always be a need for movie stars.

4. And Bullock is an excellent spokesperson for the technology. Many voters still don’t understand the intricate craft involved with a movie like “Gravity” — which explains why most questions from reporters have been about process. But talking to Variety’s Tim Gray, Bullock made it clear that she had to act in circles to convince audiences she’s a seasoned astronaut. “It was my job, with all these constraints, to figure out how to be this person,” she said. There’s no denying that Bullock, and not technical wizards, built that character.

5. Her only problem — being a recent Oscar winnerwon’t be a problem. The downside for Bullock is that she won so recently for “The Blind Side.” But that won’t be an issue if, as expected, this year’s best actress race is similar to last year’s best supporting actor competition, when all the nominees were previous winners. Bullock will likely be joined by four of the following contenders: Cate Blanchett (“Blue Jasmine”), Meryl Streep (“August: Osage County”), Judi Dench (“Philomena”), Emma Thompson (“Saving Mr. Banks”) and Kate Winslet (“Labor Day”).

If the nominations do unfold this way, the Academy will be deciding which actress deserves her second (or more) Oscar. Blanchett may be Bullock’s biggest competition with the raves she’s received for her performance in the Woody Allen comedy, yet she still won’t be the favorite. Everything can change in the coming months as the Oscar race swings into full gear, but right now, Sandra Bullock is the one to beat.