Interstellar, the new scifi space exploration epic from Christopher Nolan, has been hit by a lot of critique for its science and plot.
The one that I saw most frequently was Annalee Newitz's piece in io9, "Stop Putting New Age Pseudoscience in Our Science Fiction," but she wasn’t alone. People I know and respect found numerous reasons to hate—and love—a film that I never thought could be made. And in the midst of all this discussion, I revel in the fact that we even got the chance to have the argument.
However you may feel about the details ofInterstellar, I think it's important that its exponents and detractors both admit that it’s a landmark event for science fiction. This movie doesn’t have the flights of fancy we’d expect in a space opera, nor does it have the overdone exposition that kills other high-realism science films.
Instead, Interstellar has a story that people are paying to see and then recommending to friends. Whether that story is good or bad isn't as important as this milestone: top actors got together with a top director and a legendary scientist and proved that audiences will buy a ticket to see a movie where science is also one of the stars. That means every director who wants to try and make something like Interstellar, or something even better, can point at this proof of concept when Hollywood budgeters get cold feet.
Still, is it any good? For that, we need to go deeper.
Seven and a Half Billion's a Crowd: Let's Start a New Party in Space
Interstellartells the story of an Earth that has ecologically collapsed under the weight of human overpopulation. The species is now thinning, militaries have fallen apart, and most people are forced to be farmers just to produce enough food. Against this backdrop, a former astronaut, Cooper (Matthew McConaughey), has a bizarre vision that leads him to his former mentor, Professor John Brand (Michael Caine). Brand is now the head of NASA, and has a plan to save humanity.
This plan relies on the next of several deus ex machinae in the film. A mysterious super-intelligence has opened a stable wormhole near Saturn, which leads to a system of several planets, all of them potential human colonies.
NASA has already sent lone astronauts on one-way trips to explore each of these worlds. The only data sent back was a “yes” if they managed to land on a planet that might support a colony. When Cooper arrives, there are three planets to check, but the mission to start a settlement could be a one-way ticket. Leaving his children behind and promising to one day return, Cooper sets out to command a trip that could save the species.
A space adventure with breathtaking visuals and mind-bending physics thus ensues. Throughout, the movie contrasts humanity's, and Cooper's, limited time and desperation against the decades that the explorers burn just trying to go from place to place. To do this, a Dylan Thomas poem ("Do not go gently...") is played over key moments of void and loss.
The message, delivered in dialogue as well, is that the desperate last gasp in any life can produce fantastic feats of brilliance. The trippy finale, involving a leap of faith into a black hole, puts the capstone on this idea while remaining grounded in scientific principles.
A Director, a Writer, and a Theoretical Physicist Walk Into Hollywood
In the interest of full ethical disclosure, I have to note that I've shared a dinner table with one of the producers of this movie on several occasions: Dr. Kip Thorne, a fellow Caltech alumnus and arguably the world's most eminent expert on quantum gravity.
Described as a "consultant" on the science, in truth, Kip, who looks a little like Michael Caine and insists his students use his first name, was a driving force behind the basic idea of Interstellar. He campaigned for years to make a movie that does both science and story at the highest level.
I was at a formal dinner with Kip, the same week he'd pitched Stephen Spielberg on the film concept, and it was hard not to become infected with Kip's enthusiasm that a movie about black holes and physics could also have a deep human message.
Sometimes "Show, Don't Tell" Leads to Problems
I don't think the movie fully succeeds at its goals, partly because the high-concept science is difficult to penetrate. Much criticism has been leveled at the implausible nature of some of the speculation in the film, as well as the unusual new technologiesportrayed.
Interstellaris loaded with fantastical elements that rely on what seems like stretchy science. The movie avoids explaining these things in pedantic detail because that would be a mortal wound for the narrative flow. Instead of telling you how every little detail works, Interstellar shows you the planets and spaceships and hopes you'll trust them to have gotten it right.
Unfortunately, sometimes it errs too far away from exposition, leaving a lot of confusing elements on the screen. Planets on the edge of a black hole's point of no return, a crop blight that thrives on nitrogen, and a rotating black hole are all brought to the table—and I've seen them ripped to shreds by well-meaning critics who don't realize that these odd ideas are actually possible.
In truth, all of these things are “allowed” by science. Under special conditions, a planet could be that close to a black hole without it breaking apart. Since plants thrive on nitrogen, it would also make sense that a nitrogen-fixing bacteria or parasitic plant could become a crop blight. And above a certain size, some think that most black holes are rotating ones like Interstellar’sGargantua. For some, though, it's not enough that the science is entirely possible—it also has to be so likely that it must be mundane.
Implausible Science is Still Science
The problem is, science doesn't work that way. It doesn't obey our rules and expectations. That's part of the fun.
Science is loaded with unexpected observations and data that relies more on luck than anything that makes intuitive sense. Nature has a tendency to surprise us with inconvenient truths that even the most robust theories must adapt to absorb.
The beauty of science is that we do adjust to absorb these truths. That's what makes the process scientific. Interstellar understands this.
It lets us know by naming one of its main characters—Cooper's brilliant daughter, Murph—after Murphy's Law. Cooper restates it not as "if something can go wrong it probably will," but as the less imposing, "everything that can happen, will happen." I just wish the movie made this point with greater emphasis.
It's a more scientific way to look at the unlikely. Even Earth is a pretty unlikely planet. But it's here, and so are we. Why? Because it's a big universe out there and everything that can happen in it, will. To those who say it's impossible to have these unlikely things in a movie, I say that they're forgetting just how much wonder there is out there for the taking.
But When You Use the Implausible, You Have to Explain Yourself
Of course, there are deeper problems with the film. When Annalee Newitz says the ending is "pseudoscientific woo" where Cooper manipulates gravity using the power of love, she's not correct—but that isn't her fault. Newitz is a very smart person and Interstellar has no excuse for failing to be understood by her. The movie does a pretty terrible job explaining what Cooper and Murph are doing at the end of the film, and why it matters for the ultimate solution of humanity's existential problems.
While in the end it's about gravity, impenetrable storytelling makes it difficult to separate gravitational science from the thematic element that love is a motivation for Cooper’s actions, not a real physical force.
Since most people last took physics in high school, it’s a major failing that the film expects us to know where science ends and metaphor begins. Nolan should’ve traded some of the less important material out for scenes that would show audiences the line between prosaic science and poetic themes.
In between those themes, though, Interstellaroffers some awesome stellar dynamics, spacecraft piloting tricks, and dramatic moments that genuinely do connect with those watching. Seeing those things play out, I forgave the moments of clunky dialogue and off-balance pacing.
The spaceship piloting was a particular delight. One of the biggest plot drivers is the characters' constant need to balance their three most important resources: data, fuel, and time. It costs them fuel to collect data on the various planets, but the more data they have, the more time they save, and the sooner they get back to the families they've left behind on Earth. That close to a black hole, where time can dilate so that your children on Earth age 50 years while you age a day, it’s critical to save time.
Cooper and his crew argue, innovate, and pull maverick tricks to get the most bang for their buck and find a planet that can save humanity before their luck runs out. That's what Interstellar is really about. The film’s strength lies in that drama, which echoes the lesser-known Europa Report, which I'd recommend to people who enjoy those elements.
On top of that drama, there’s also the fact that Interstellar has some of the most exciting, and accurate, space visuals that have ever appeared on film.
Not Just a Science Movie: Also a Movie that Makes Science Happen
Gargantua is by far the visual high point. Typically, a scifi film would farm out its visual effects to artists who would trade scientific realism for aesthetics. Well, not so for Interstellar. Instead, Kip worked with the VFX team to do real science.
Using movie-making computers that a physics department normally couldn't afford for rendering pictures, they put real astrophysics into the math and got back something that isn't just beautiful, but that will result in a couple of academic physics publications because no one has ever accurately rendered a black hole that way before.
I asked Kip which aspect of imaging Gargantua he thought was the coolest (my word, not his), and he replied that it was “insights into the caustic structure of a camera's past light cone when it is near a black hole, and how those caustics affect gravitationally lensed images.”
Of course, that requires a little bit of translation from “eminent physicist” to “anyone else.”
What he’s talking about is the fact that a black hole’s gravity is so high that it can bend rays of light around itself. That’s called gravitational lensing, and the black hole’s gravitational lensing is able to affect the dispersion of light both into the future and into the past (“past light cone”). That means, in short, that the high gravity of a black hole can make light look really strange to an observer close to the black hole.
However, most black hole renderings haven’t simulated taking images through a realistic camera.
Camera lenses also bend light and the pattern of that is called the “caustic structure.” For a camera close to the black hole, the caustic structure of the camera and the gravitational lensing of the hole play together in odd ways. You get some weird effects in your final picture that you would not see at a distance.
That’s important for future scientists—the first images of a black hole will probably come from a space probe’s camera, and thanks to Kip and Interstellar, we’ll have an idea of what to expect.
Kip tells me that he has a paper due out soon that explores the physics of this in detail; I recommend you check it out if you can follow that sort of physics.
If you’re less versed in spacetime physics, I’ll point you in the direction of Kip’s latest book The Science of Interstellar, released as a companion to the film. Both of those documents bear witness to the fact that Interstellar is a great marriage between Hollywood and real science.
The Dramatic Challenges are Also Driven by Science
There's more, still, though. The spacecraft used in the film are mostly realistic technology with realistic limitations. The first of these limitations is one that you don't see a lot outside of the futurism and science fiction worlds: the simple fact that rocket power isn't going to be enough to get all of humanity off of a dying Earth.
It's true. The Earth is the Titanic and there aren't enough lifeboats with current technology. NASA in the film is fully aware of this and Professor Brand's plan to save humanity is designed in a way doesn't necessarily save all the humans. While Cooper and his crew are off looking for a new home, Brand will try to solve the equations of quantum gravity that could get the rest of humanity off of Earth. That's "Plan A."
Yet the pursuit of science doesn't come with guarantees and Professor Brand has a backup plan. His daughter (Anne Hathaway, confusingly also a professor and also referred to mostly as "Brand") will go on the mission and transport a cache of thousands of frozen human embryos. This is "Plan B" and it relies on the use of an artificial uterus. Brand (the younger) is the only person on the mission capable of carrying a child, after all.
Babies Out of a Toaster: Could Plan B Really Happen?
Artificial uterus development is going on right now. It’s called ectogenics, and it is important both for reproductive science as well as for future technologies that could grow human organs from stem cells.
In 2003, Dr. Helen Liu of Cornell showed that she could grow animal embryos under artificial conditions by supplying engineered womb tissue, amniotic fluids, hormones, and nutrients in a metaphorical test tube. She’s continued her work, even growing a human embryo for less than two weeks, but human trials are going to be tricky due to laws imposing that two-week limit. Still, eventually there will be an artificial womb, and because of that inevitability there are already people talking about the ethics of such a device.
Interstellar, which is no big event for feminism, hops over those issues in favor of a technology that allows you to grow space colonists in the microwave, and I have to admit that it’s kind of cool to imagine. With that technology, Plan B would be possible in the real world—whether or not Earth is dying.
In the real world, Kip himself, and many others, are working on a coherent theory of quantum gravity that could lead to Plan A in the far future. It's true that a lot of world saving technologies could be built if we knew how to control gravity, but a theory of gravity is just the horse. We'll need to build the cart, too, and it will be amazing.
For one thing, control over gravity would make it possible to build miniature, safe black holes at will. Either by harnessing Hawking Radiation, or by making these black holes rotate, we could construct reactors that convert matter entirely into energy. In 2009, two Kansas State University physicists proposed that such an energy source could power spacecraft. Think nuclear fusion is a source of amazing power? Well, total conversion reactors are several orders of magnitude more incredible.
Then there's the "gravity drive." Gravity drives, which have been researched by NASA, use some kind of gravity-manipulating engine to literally make spaceships "fall up," and as a result, the energy and fuel needed to get off of Earth is theoretically reduced. Combine that with the fact that you've got the total conversion reactor from the previous paragraph, and it could be a lot cheaper to get into space. Hypothetically.
The problem is the practice. We don't know how much energy it will take to run a gravity drive, and we can't really be sure if the equations for gravity are something that are ever going to be solved. A few projects are giving us data that might help, like the LIGO project at Caltech (cofounded by Kip) that is trying to detect gravitational waves, or the search for the mass-determining Higgs Boson that has made so many headlines for CERN's Large Hadron Collider. But these are just pieces of a huge puzzle. Furthermore, even once we understand gravity, it's going to take a lot of engineering efforts to make machines that control it. I wouldn't hold my breath for gravity drives.
Kip agrees. When I asked him about machines that might be able to launch huge space stations, like the “Cooper Station” depicted in the film, he replied, Anything like what got Cooper station off the ground is highly speculative and probably not allowed by the laws of physics; but we don't know. If it is possible, it is centuries and perhaps millennia in the future.”
But then, I remember Murphy's Law. I wouldn't be shocked if what we least expect is what ends up happening. If there's anything that Interstellar gets right about science, it's the fact that reality doesn't care what we expect to be true. It's going to surprise us at every turn.