Kip Thorne, the 74-year-old theoretical physicist whose ideas provided the original inspiration for Christopher Nolan's blockbuster Interstellar, is in his home office in Pasadena, drinking a Diet Sunkist and discussing the moment, as a kid, when he decided to become a scientist. "As early as I can remember, I wanted to be a snowplow driver," the Utah native says. "When you grow up in the Rocky Mountains, like I did, you see the snow drifts piled up six feet high and you're two feet, so it's impressive."
When Thorne was eight, though, his mother took him to an astronomy lecture that threw those snow-drifts into severe perspective. "Afterwards, she suggested we make a model of the solar system on the street where we lived," Thorne recalls. "The plan was to draw the sun as a four-foot diameter circle on the corner, then the planets, running down the street, to scale. We took out a long tape measure, and the shocking thing was to find that Mars was down on the next block Pluto was out in the next town!"
Thorne was hooked, and his interests outgrew the solar system. In graduate school at Princeton, his focus shifted to black holes, and from there to what he calls "hypothetically traversable wormholes" — an idea that arose while he was writing his 1994 book, Black Holes and Time Warps. "I became interested in this question of whether you can build wormholes for interstellar travel," Thorne explains. "I realized that if you had a wormhole, the theory of general relativity by itself would permit you to go backward in time." He floated this seemingly fanciful notion in a scholarly paper, prompting a wild range of reactions among his colleagues. One called it "wonderful"; another "phoned my wife and asked, 'Has Kip gone crazy?"' Thorne says, laughing.
Undaunted, he stuck with the subject, getting into arguments along the way with his friend Stephen Hawking about matters like the theoretical durability of time machines: "We went back and forth and eventually agreed that the answer is held tightly in the grips of the laws of quantum gravity."
Thorne says he's always wanted to bring scientific matters out from within the walls of academia to the public. This desire has resulted in mass-market books, as well as incursions into the movies: Thorne schooled Carl Sagan in wormholes while Sagan was writing the screenplay for Contact, and over the years he's batted different script ideas back and forth with Hollywood producer (and Sagan's old friend) Lynda Obst. One of their ideas made its way to Christopher Nolan's brother Jonathan, a screenwriter, and the Nolan brothers reworked it into Interstellar, with Thorne consulting on the science of the film. The director wanted this component to be as realistic as possible, the sci-fi context notwithstanding. This manifested in questions about the film's plot points, and about its look.
"Chris wanted things like worm holes depicted in the way a person really would see them if they traveled beside them or through them," says Thorne. "I worked hand in hand with the visual effects team to take equations from general relativity and turn them into the things you see on screen." Thorne also wrote a tie-in book to be published alongside the movie's release, all in hopes of ensnaring the curious and pulling them in even deeper. "My goal for the film was to show the world how fascinating real science can be — the marvelous things the laws of physics can give rise to," he says, "and the things that humans are capable of achieving through science."