“Gravity” has the most hype of any film this year — and for good reason. The Oscar hopeful set a record for biggest October opening last week, bringing in an estimated $55.6 million (beating out former front-runner “Paranormal Activity 3,” which earned $52.6 million in 2011). It was also the biggest opening ever for A-list co-stars Sandra Bullock and George Clooney, who have long sought the perfect film to work on together. Whether you’ve already seen it in the theater or are waiting for the buzz to die down, here are some of the secrets to this week’s hottest movie: