Cooper: We used to look up at the sky and wonder at our place in the stars, now we just look down and worry about our place in the dirt.
Cooper: Mankind was born on Earth. It was never meant to die here.
CASE: This is not possible.
Cooper: No. It's necessary.
Doyle: You can't just think about your family. You have to think bigger than that.
Cooper: I'm thinking about my family and millions of other families.
Dr. Brand: Do not go gentle into that good night; Old age should burn and rave at close of day. Rage, rage against the dying of the light.
Chosen answer: They do not still have gravity. Romilly is actually floating, but nothing is ever shown from behind his back, so the floating is gone unnoticed. In fact, during some shots of Romilly, you can see his feet floating behind him.
Casual Person