[Note: The post contains major spoilers for Interstellar. An initial, spoiler-free assessment of the film is presented in my November 5, 2014 review for St. Louis Magazine.]
Christopher Nolan has created some staggeringly ambitious science-fiction films over the past decade, but Interstellar is the first that brings the genre's scientific components decisively into the foreground. Most conspicuously, the film’s heroes are actual physicists, engineers, biologists, and geographers—and not the curiously incurious “punk rocker” sort, either. There’s something quaint about filling the cast of a sci-fi feature with characters who are genuine researchers and explorers, the sort of individuals who are fundamentally driven to illuminate, catalog, and harness the natural universe. One could even call Nolan’s film classical in its reverence for the scientist-hero, save that the PhDs of cinematic sci-fi’s midcentury golden era were just as likely to be deranged villains.
Science is also an essential aspect of Interstellar’s plot, and not merely in the broad sense that it is a work of space-based fiction. The film’s story is one of quantities and dimensions, where the characters (and humanity in general) are entrapped by fearsomely concrete deficits and surpluses. Earth has suffered a massive population collapse due to the ravages of climate change and an inter-species plant pathogen known as Blight. The future of the survivors is grim, as the remaining subsistence crops are falling one by one to the Blight’s withering touch. Unbeknownst to most of Earth's population, the Blight is also emitting so much nitrogen that the proportion of oxygen in the atmosphere is approaching unbreathable levels. The end of Homo sapiens is to be death by starvation and suffocation.
Corn farmer and ex-NASA test pilot Cooper (Matthew McConaughey) has an painfully vague but unshakeable hope that humanity will find the means to save itself from such a fate. It’s a strangely myopic perspective for a man who is otherwise depicted as droll and world-weary. One could say that Interstellar itself indulges in such techno-utopianism, as Cooper's prediction is ultimately proven correct, albeit a bit off the mark regarding the “how” and the “when”. Humankind's salvation lies not in some earthbound agricultural discovery, but in the colonization of distant, habitable planets free from dust storms and Blight. This feat is accomplished through the labors of earthly scientists, but also with a considerable assist from unseen, hyper-advanced beings.
Once the crew of the experimental craft Endurance leaves Earth, Interstellar creates drama primarily through the punishing parameters of space travel. As in Alfonso Cuarón’s slicker and more stripped-down thriller, Gravity, stark metrics such as velocity, mass, acceleration, pressure, and temperature define the astronauts’ fates. When physicist Romilly (David Gyasi) confesses his terror at the thought of mere millimeters of aluminum separating him from airless void, Cooper reassures him by noting that some championship solo sailors do not know how to swim. Not only is physical peril a part of an explorer’s job description, it’s what defines our species. As Cooper's old colleague Professor Brand (Michael Caine) observes, Earth is actually a somewhat unfavorable environment for the human organism. Our story has been one of struggle under hostile conditions since the day we crawled out of the ooze.
What makes Interstellar distinctive among space thrillers is the characters’ contention with a whole new parameter: relativity. The longer the Endurance takes to complete its mission, the closer earthbound humanity lurches towards extinction. The conventional, rocket-powered journey from Earth to the inter-galactic wormhole near Saturn takes the Endurance over two years, but that’s the least of the crew's troubles. The three candidate Earth 2.0's on the far side of the wormhole orbit a massive black hole named Gargantua, which subjects nearby objects (and people) to an unfortunate time dilation effect. The upshot is that a mere hour on the innermost planet’s surface corresponds to seven years on Earth. The time dilation becomes yet another factor that the crew must consider in each decision, a variable that must be weighed against a multitude of others. Interstellar’s performers portray this aspect of the story fantastically, and watching their characters react as the seemingly outlandish effects of relativity become reality is one of the film’s many novel pleasures.
Were it simply a white-knuckle astronautical adventure tale, Interstellar would be a visceral, memorable work of Hollywood entertainment, and little more. However, as Christopher Nolan joint, the film is also engaged with Big Ideas, and it proclaims this fact in a thunderous voice at every opportunity. It’s easy to criticize the filmmaker’s penchant for operatic earnestness and screaming DayGlo dialog, but these elements fit Interstellar in ways that they never did with Nolan’s Batman trilogy, The Prestige, or Inception. As extraordinary as the events of those films might be, Interstellar is in entirely different league, if only in terms of stakes. It is, after all, the story of how the whole of humanity breaks its terrestrial shackles and escapes its looming extinction. What better occasion for a grave, sincere tone and sweeping, guileless speeches?
In retrospect, it’s apparent that almost every line and shot of Interstellar lays the groundwork for the film’s climactic revelations. Although Nolan and his brother Jonathan are (often rightly) disparaged for their needlessly convoluted and sprawling screenplays, Interstellar is remarkably lean for a film with a running time that clocks in at just under three hours. There are barely any red herrings, abandoned subplots, or whimsical digressions crowding for the viewer’s attention. Every jot of the film reveals some new narrative swerve or essential bit of characterization. It is a relentlessly focused film, even if this is not always apparent in the moment. That focus ultimately falls on the childhood bedroom of Cooper’s daughter Murphy (Mackenzie Foy).
As Amelia Brand (Anne Hathaway) explains to Cooper at one point, time can slow down and speed up owing to relativity, but it cannot be reversed, at least by any means available to primitive, four-dimensional creatures such as human beings. The past cannot be changed. This neatly foreshadows the seemingly unsurmountable obstacles facing the Endurance in the film’s final act. Professor Brand’s Plan A—to move humanity off Earth by harnessing gravitation—proves to be a sham, his critical equation apparently unresolvable. Murphy (Jessica Chastain), having grown into a brilliant theoretical physicist in her own right, might be able to accomplish what her mentor could not, if she had more time and a set of observations from beyond a black hole’s event horizon. She has neither. Cooper develops a plan to extract data from Gargantua using the robot TARS as a probe, but by the time the information reaches Earth, humanity will have long turned to dust.
Resolved to the fact that he will never see his children again, Cooper ultimately elects to sacrifice himself, allowing Amelia to escape Gargantua’s gravitation and proceed to the third and final candidate planet. (Conditions permitting, she can then enact Plan B’s “population bomb,” becoming a surrogate mother to all that remains of Homo sapiens.) When Cooper falls into the black hole, however, he emerges within a tesseract, a three-dimensional representation of time that has been constructed specifically for him by the same beings that created the Saturnine wormhole. Briefly disoriented, Cooper eventually realizes that he is “behind” Murphy’s bookcase, and that like some Narnian version of Vonnegut’s Trafalmadorians, all moments in time are available to him. The rub is that his field of view is limited to his daughter’s bedroom, and that he can exert only tiny gravitational nudges through the walls of the tesseract.
Overcome at the sight of his daughter and frantic to prevent the Endurance’s doomed mission from ever occurring, the unseen Cooper pleads in vain with Murphy and his past self, going so far as to knock over books to spell out “S-T-A-Y” in Morse code. (This doesn’t work, of course, because his past self has already dismissed this message as a childish fabrication by his distraught daughter.) McConaughey is especially riveting here, as Cooper sobs and screams himself hoarse, his unflappable cowboy demeanor evaporating while he rages against his own impotence. It’s a naked, anguished moment, recalling Claire’s futile wailing at the fuzzy image of her dream-self in Wim Wenders’ Until the End of the World.
It is TARS who points out what Cooper, drowning in his parental angst, cannot see: the benefactor beings did not create the tesseract so he could alter his own past, but so he could prevent the demise of humankind. It’s at this juncture that the Cooper realizes he must trace out the binary coordinates in dust that once brought him to NASA’s door. He’s traveled across the universe not to change history, but to ensure that it happens exactly as it should. What’s more, he’s there to convey the data from beyond the event horizon across the years and light-years to someone in a position to receive it. That someone must also be able to make sense of the results, solve Brand’s equation, and rescue humanity from its dying home world. That someone is, of course, adult Murphy. Cooper apprehends that the fifth-dimensional entities who created the wormhole and tesseract are not members of an alien species. They are future humans, reaching back through time to ensure their own survival, with father and daughter as their tools.
Interstellar is thus revealed as not only a space travel tale, but a time travel tale, one in which the message sent between past and future is crude in nature, but profound in content. One thinks of Jean-Dominique Bauby in The Diving Bell and the Butterfly, blinking out his life’s story with his left eye, one letter at a time, to be printed into a book and read by millions of people. Suddenly, Amelia’s earlier groan-worthy monologue about the timeless power of love seems not only salient, but insightful (if only inadvertently). Only someone who loved Murphy would know exactly where and when to reliably find her. Only such a person would know how to convey the unifying equation to her using only gravitational twitches. Only love would send Murphy back to her childhood room to retrieve her watch, a gift from the father that she despises but nonetheless hopes will return.
Depending on the conceptual model one favors for time travel, this may or may not leave Interstellar with a yawning paradox at its center. (How did humanity first unify gravitational theory and escape Earth without the assistance of their future selves? The Möbius loop has to start somewhere, doesn't it?) The film does seem to provide a riposte to Stephen Hawking's glib objection to time travel: that it probably is not possible given the evident absence of visitors from the future. In Interstellar's universe, future humans, while able to traverse time as easily as we might stroll down the street, can only be perceived imperfectly by our lowly four-dimensional selves. (This mathematical hurdle was highlighted over a century ago in Edwin Abbott's visionary satirical novel, Flatland, and more recently in Nic Pizzolatto's crypto-weird mystery series True Detective, also starring McConaughey.) The best that the hyper-humans of tomorrow can muster is some gravitational tinkering to give their ancestors a window to save their own skins.
Such cosmological thought experiments certainly excite the imagination, but time travel in fiction serves as a basis for philosophical as well as scientific rumination. To some extent, it has assumed the role that omens and curses used to play in ancient tragedies, where a prophecy sets events into motion that ensure its own fulfillment. Gussied up with a bit of of theoretical physics, the conceit of time travel establishes a just-believable-enough stage for a study of causation and free will. In such a context, Interstellar's recursiveness, like that of Oedipus the King and Macbeth, is a bug rather than a feature. It forces the viewer to confront the difficulty (impossibility, even) of pinpointing agency in a material universe of incalculable, interlinked causes and effects. Like a Weird Sister or spectral Banquo, Murphy's bookshelf poltergeist provokes Cooper to take actions he might not have otherwise taken, actions that nonetheless express his repressed yearnings. The fact that the ghostly presence was Cooper himself does not negate the challenge that Interstellar poses to our conception of metaphysical freedom, but rather adds a significant space-time wrinkle.