7 Interstellar questions explained by Jonah Nolan and Kip Thorne at NASA's Jet Propulsion Laboratory

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Mar 31, 2015

Love it or hate it, Interstellar certainly earns points for getting mainstream audiences to attempt to wrap their heads around the science at the core of Christopher Nolan's intergalactic epic. It's no secret that since its release last November, nitpicking the more confusing scientific concepts and logic gaps in the narrative became an Internet pastime. Plus, there's that ending that many feel needs graphs, pie charts and a slide rule to get to the bottom of.

So when Blastr was invited to the Jet Propulsion Laboratory in Pasadena to chat about the film's Blu-ray release on March 31 with Interstellar's screenwriter Jonathan Nolan and celebrated physicist Kip Thorne, getting answers to even a few of our stack of burning Interstellar questions became the priority. Thus,  we didn't waste our valuable minutes wondering how Matthew McConaughey's Coop could be drinking a beer when there's a devastating global famine raging (are they clone hops?) or why robotic TARS didn't just hustle Brand (Anne Hathaway), Doyle (Wes Bentley) and Coop around the scary wave planet from the start, or why Cooper's son named his son Cooper Cooper. Instead we focused on meatier questions, which Nolan and Thorne were game to answer.

We also gathered more answers from their joint lecture for JPL employees. A few hundred of the finest scientific minds from Caltech and NASA, many responsible for the Mars Rover missions and planning for future manned space exploration of Mars, also grilled the pair, and it was comforting to know a lot of them were a little confused by some of what Interstellar was throwing down. [Spoilers below!]

Revelation 1:  The science was woven into the film from the very start.

Jonah Nolan: The beauty of the project is the way that it came together. I came to the project after Kip, so the collaboration clicked into it from the very beginning. The script sprang from the science and from our conversations, which meant for me that they were never at cross purposes. It was just a question of talking with Kip, reading his book and some of the other literature on these topics, where you realize the universe is far stranger than anything I could dream up by myself. For us, it was a question of curating some of those phenomena, and we got them right, and then trying to find a human story that threaded through the middle of it and bring it back to the emotional level.

Kip Thorne:  I think this is so different from any other film I know of in that the science was there from the beginning. Jonah and Chris were so wonderful about growing the story symbiotically with the science. I never saw any significant tension between the story and the science.

Revelation 2:  The death of tech in the film, like GPS and MRI machines, is based on informational extinctions in history.

Jonah Nolan: Kip and I spent a memorable afternoon with some fantastic scientists that Kip pulled together to talk through all the different ways human life could be extinguished or hobbled on our planet. It was a very depressing afternoon. [Laughs] I remember being struck by the fragility of life here. Everyone who has grown up in the West and has been fortunate enough to live through a rather peaceful period, every year everything seems a little better. It's hard for us to imagine periods when things go backwards, but they do very, very frequently.  Just in the last 2,000 years, we can identify at last half a dozen periods in western culture where technologies were lost that ancient civilizations had that we still don't fully understand exactly, so you know that there's been knowledge lost since as early as the Middle Ages. What we know about that period survives because of beautifully transcribed manuscripts out on some rocky island on the North Sea. Although it's not our experience, it's frighteningly easy to imagine technology backsliding.

Revelation 3: The incredible visuals inside the wormhole are based on real imagery, even though Chris Nolan tinkered with it.

Kip Thorne: In the film, Romilly (David Gyasi) bends a piece of paper and sticks a pencil through it to illustrate a wormhole. The images in the wormhole were generated when I sat down with the team at Double Negative in London, led by Paul Franklin, who won the Academy Award for this film. We wrote down the mathematics of the wormhole, which had adjustable light, adjustable size and an adjustable opening, and we then made images of what the camera would see for various sizes and shapes of wormholes. Chris Nolan and Paul Franklin looked at the images and chose what would be the shape of the wormhole. Inside gives you this beautiful crystal-ball-like image of the wormhole where you see gas clouds, dust clouds, stars and nebulae on the other side of the wormhole. But then that presented a problem because we wanted to travel through the wormhole, but ... that shape of wormhole was wonderful to look at from the outside, but then you've got a boring trip because it's such a short wormhole. When Chris Nolan saw this he said, "Well, go back to the drawing board, and when we go through the wormhole, we'll choose a different shape." We had an artist go in and make a more interesting trip through a wormhole that is based on trips in wormholes of various sizes and shapes. So this was the one place where there was compromise in the science.

Revelation 4:  You thought Matt Damon was the bad guy, but it's really time.

Jonah Nolan:  The one thing we are always running out of is time, and this film doesn't have a traditional antagonist in that time seemed to be the antagonist. That led to long conversations that Kip and I settled, and then were reopened when my brother did his draft. We settled on black holes as a great persona for a way to manipulate and alter time.

Kip Thorne: The idea that, down near a black hole, time moves more slowly than far way is an old idea that goes back to Einstein's general relativity. Jonah and Chris wanted a much bigger time difference. Chris wanted one hour on Miller's planet, which is in orbit around this black hole, to be seven years on Earth. I said to Chris, I'm quite sure that's not possible, and you won't get more than about three hours on Earth to two hours down there. Then I went home and I thought on it and I did the calculations for a very fast-spinning black hole, but I was sure it wouldn't allow anything like one hour to seven years ... but, lo and behold, it did. In principle, it was possible, as the law of physics doesn't disallow it.

Revelation 5:  The gravitational anomalies also do a cool coin trick.  

Jonah Nolan: I liked the idea that gravity has certain characteristics that suggest it's stronger than it is, and there's an aspect of it being missing, so it started to stand out as something that had a bit of mystery to it. What's also fantastic about it is that it's probably the concept most familiar to us and a part of our life that's less tactile.

Kip Thorne: I remember vividly that Jonah was pushing me about wanting something that shows up on Earth that tells us something weird is going on in the universe. Out of this brainstorming, I was thinking back to my years as a graduate student when I studied an alternative series of gravity where the strength of gravity can be altered by some kind of a field that couples to it. Gravity could fluctuate in unexpected ways because of some field coming in that influences from the fifth dimension, since we have five dimensions in the film. In the film, there's a scene where Murph (Mackenzie Foy) is in her bedroom, staring at a strange pattern of bars on the floor of her room, and Coop tosses a coin across the pattern. If you look at it very carefully, that coin does not go up in a parabolic arc. It goes up, then plunges to the floor over one of the ridges of dust as a gravitational anomaly.

Revelation 6:  The planets on the other side of the wormhole have a secret "sun."

Kip Thorne: In this particular case, the heat and light for all of the planets is coming from the accretion discs. If it were like the accretion discs that astronomers study, it would be 100 million degrees and would emit so many intense X-rays that the crew of the Endurance would be fried as soon as they got out of the wormhole. Thus, the accretion disc in this film is a very cold one. It may look spectacular, but it's just sitting there cooling down to the temperature of the sun, in fact, a temperature of 6,000 degrees. Miller's planet is still pretty close to the accretion disc, and it's probably closer than you'd want to be.

Revelation 7:  The last few minutes of the film, in which you're left wondering if aliens or humanity from the future actually saves our cumulative bacon, is where science steps off, so go with it.

Jonah Nolan: In a sense, [we] knew we had to take several leaps and flights of fancy, and the wormhole is the best example. Their existence in the film suggests the intervention of an alien intelligence. Realistically, the appearance of them would suggest something outside of naturally occurring phenomena:  a door, a threshold. If the other end happens to be in a solar system, or a black hole system, with several viable candidates for human life, now you get a sense of why it's there. We don't know what happens inside the event horizon of a black hole, and one of the ideas underpinning the film is that the universe is so big and so hostile that our manipulation of its forces is so primitive at this point. Our understanding of the structure of it is incredibly incomplete.  The relationship to space/time is very simple here, but potentially very complicated as we venture out into the unknown.  With the film building steadily on good science and observable phenomena, we ask in the closing minutes ... you have to take that leap into the unknown and ask questions about our existence. We wanted to pull all those ideas into one sequence with an emotional arc pinned to it as well. The invitation to the audience is to try to imagine that our experience in the universe, when we are capable of understanding beyond our experience, is very strange indeed, and we wanted to humbly hint at that.