Franklin knew that his computers would do anything he told them to. That was a problem and a temptation. “It's very easy to fall into the trap of breaking the rules of reality,” says Franklin, a senior supervisor of Academy Award-winning effects house Double Negative. “And those rules are actually quite strict.”
So he asked Thorne to generate equations that would guide their effects software the way physics governs the real world. They started with wormholes. If light around a wormhole wouldn't behave classically—that is, travel in a straight line—what would it do? How could that be described mathematically?
Thorne sent his answers to Franklin in the form of heavily researched memos. Pages long, deeply sourced, and covered in equations, they were more like scientific journal articles than anything else. Franklin's team wrote new rendering software based on these equations and spun up a wormhole. The result was extraordinary. It was like a crystal ball reflecting the universe, a spherical hole in spacetime. “Science fiction always wants to dress things up, like it's never happy with the ordinary universe,” he says. “What we were getting out of the software was compelling straight off.”
McConaughey explores another world in Interstellar (top). Thorne’s diagram of how a black hole distorts light.
Diagrams courtesy of Kip Thorne
Their success with the wormhole emboldened the effects team to try the same approach with the black hole. But black holes, as the name suggests, are murder on light. Filmmakers often use a technique called ray tracing to render light and reflections in images. “But ray-tracing software makes the generally reasonable assumption that light is traveling along straight paths,” says Eugénie von Tunzelmann, a CG supervisor at Double Negative. This was a whole other kind of physics. “We had to write a completely new renderer,” she says.
Some individual frames took up to 100 hours to render, the computation overtaxed by the bendy bits of distortion caused by an Einsteinian effect called gravitational lensing. In the end the movie brushed up against 800 terabytes of data. “I thought we might cross the petabyte threshold on this one,” von Tunzelmann says.
“Chris really wanted us to sell the idea that the black hole is spherical,” Franklin says. “I said, ‘You know, it's going to look like a disk.’ The only thing you can see is the way it warps starlight.” Then Franklin started reading about accretion disks, agglomerations of matter that orbit some black holes. Franklin figured that he could use this ring of orbiting detritus to define the sphere.
Von Tunzelmann tried a tricky demo. She generated a flat, multicolored ring—a stand-in for the accretion disk—and positioned it around their spinning black hole. Something very, very weird happened. “We found that warping space around the black hole also warps the accretion disk,” Franklin says. “So rather than looking like Saturn's rings around a black sphere, the light creates this extraordinary halo.”
That's what led Thorne to his “why, of course” moment when he first saw the final effect. The Double Negative team thought it must be a bug in the renderer. But Thorne realized that they had correctly modeled a phenomenon inherent in the math he'd supplied.
“We’ve forgotten who we are,” says Matthew McConaughey’s Cooper. “Explorers, pioneers — not caretakers.” That could be Christopher Nolan speaking about movies in this timid age of old genres endlessly recycled and coarsened. He’s the rare filmmaker with the ambition to make great statements on a grand scale, and the vision and guts to realize them.
Nolan is also a consummate conjuror. Memento, his amnesiac movie, ran its scenes in reverse order. In The Prestige, magicians devised killer tricks for each other and the audience. Inception played its mind games inside a sleeper’s head, and the Dark Knight trilogy raised comic-book fantasy to Mensa level. But those were the merest études for Nolan’s biggest, boldest project. Interstellar contemplates nothing less than our planet’s place and fate in the vast cosmos. Trying to reconcile the infinite and the intimate, it channels matters of theoretical physics — the universe’s ever-expanding story as science fact or fiction — through a daddy-daughter love story. Double-domed and defiantly serious, Interstellar is a must-take ride with a few narrative bumps.
In the near future, a crop disease called “the blight” has pushed the Earth from the 21st century back to the agrarian 1930s: the world’s a dust bowl, and we’re all Okies. In this wayback culture, schools teach that the Apollo moon landings were frauds, as if America must erase its old achievements in order to keep people from dreaming of new ones.
Farmer Coop, once an astronaut, needs to slip this straitjacket and do something. So does his daughter Murphy (Mackenzie Foy); she’s getting “poltergeist” signals from her bookshelves. A strange force leads them to a nearby hideout for NASA, whose boss, Dr. Brand (Michael Caine), drafts Coop to pilot a mission to deep space. With Brand’s daughter Amelia (Anne Hathaway) and two others as his crew, Coop is to find a wormhole near Saturn that may provide an escape route for humanity. “We’re not meant to save the world,” Brand says. “We’re meant to leave it.”
Coop, a widower, wasn’t meant to leave his children. Son Tom (Timothée Chalamet) can manage; but the precocious Murph sees abandonment and betrayal in Dad’s journey to save billions of humans. Coop, who thinks a parent’s main role is to be “the ghosts of our children’s future,” shares Murph’s ache. He needs her. He goes out so he can come back.
What’s out there? New worlds of terror and beauty. Transported by the celestial Ferris wheel of their shuttle, Coop and the crew find the wormhole: a snow globe, glowing blue. One planet it spins them towards has a giant wall of water that turns their spacecraft into an imperiled surfboard. Another planet, where treachery looms, is icy and as caked with snow granules as Earth was with dust. Interstellar may never equal the blast of scientific speculation and cinematic revelation that was Stanley Kubrick’s 2001: A Space Odyssey, but its un-Earthly vistas are spectral and spectacular.
Someone on the icy planet says, “Our world is cold, stark but undeniably beautiful.” Shuttling between the grad-school blackboard and the family hearth, this undeniably beautiful film blows cold and hot, stark and sentimental by turns. Taking the visual wow factor as a given, you may feel two kinds of wonder: a child’s astonishment at the effects and a bafflement that asks, “I wonder why that’s happening.”
It’s not just that the rules of advanced physics, as tossed out every 15 minutes or so, are beyond the ken of most movie-goers. It’s also that some scenes border on the risible — a wrestling match in space suits — and some characters, like Amelia, are short on charm and plausibility. In story terms, her connection with Coop is stronger than that of the two astronauts in Gravity. But Sandra Bullock and George Clooney gave their roles emotional heft, in a film more approachable and affecting than this one.
If the heart of Interstellar is Coop’s bond with Murph, its soul is McConaughey’s performance as a strong, tender hero; in the film’s simplest, most potent scene, he sheds tears of love and despair while watching remote video messages from his kids. He is the conduit to the feelings that Nolan wants viewers to bathe in: empathy for a space and time traveler who is, above all, a father.
With Interstellar, Nolan’s reach occasionally exceeds his grasp. That’s fine: These days, few other filmmakers dare reach so high to stretch our minds so wide. And our senses, all of them. At times, dispensing with Hans Zimmer’s pounding organ score, Nolan shows a panorama of the spacecraft in the heavens — to the music of utter silence. At these moments, viewers can hear their hearts beating to the sound of awe.
Read next: Watch an Exclusive Interstellar Clip With Matthew McConaughey