If ‘Interstellar’ Were Made Today, What Would Be Different?

For its 10th anniversary, the science advisor for “Interstellar” discusses the film’s impact and how new information about gravitational waves could have changed it.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

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• 0:18Speaker 01

  If the movie Interstellar was made today, what would be different?

• 0:22Speaker 02

  Christopher Nolan was describing the wonderful things he could have done with gravitational waves if only he had kept them in the movie. Then said, well, there's no turning back time.

• 0:34Speaker 01

  It's Monday, December 23rd, and you're listening to Science Friday.

• 0:42Speaker 01

  I'm Sci-Fry producer Kathleen Davis. The sci-fi film Interstellar turns 10 years old this month. For a lot of us, it was our first encounter with some pretty advanced astrophysics, taking sci-fi concepts like wormholes and time warping and backing them up with actual science. Now we're revisiting the impact that movie science had on pop culture and how astrophysics has advanced in the past decade. If it was made today, what would be different? Here's Ira Flatow with the movie's science advisor, Dr. Kip Thorne.

• 1:15Ira Flatow?

  He's also professor of theoretical physics at Caltech. And since the film's release, he won a Nobel Prize for his contributions for the detection of gravitational waves generated from black holes. Welcome back to Science Friday. Good to have you.

• 1:30Speaker 02

  Great to be here, Ira. Thank you for inviting me.

• 1:33Ira Flatow?

  Yeah, you were, as I say, the science advisor for the movie. Remind us how the movie came about, because you played a pretty big role in that too, right?

• 1:43Speaker 02

  Yes, well, the movie began when a former girlfriend of mine, Linda Opes, called me up and said, would you like to brainstorm with me for a movie? I had helped her and Carl Sagan a little bit with the movie Contact, on which Carl had played a role similar to mine on Interstellar in the end. And so I said, yes, of course. I thought, how better to reach a very large audience with the beauties of astrophysics than... Through a movie like this. And so we brainstormed and Steven Spielberg's assistant came around to visit Linda a few weeks after we started brainstorming and asked her what movies she was thinking of doing. And she described the movie we were thinking about.

• 2:27Speaker 02

  And he went back, talked to Steven. Steven called her up and said, can you have a treatment on my desk by Monday? So we drew up a treatment, a very short treatment, about eight pages long, that just described the movie, the characters, and a little bit of the science in the movie. And Steven called back and said, I would like to direct it. I've never heard of him moving, moving that fast. But so they brought on Jonah Nolan, Jonathan Nolan, Christopher Nolan's brother, to write the screenplay. And Jonah went through three drafts of the screenplay under the oversight of Steven Spielberg and in interaction with me, a lot of brainstorming with me about additional science that would be on what

• 3:12Speaker 02

  Linda and I had started with. But then, along in that process, Christopher Nolan, Jonah's brother, said to him, if Spielberg drops out, I might be interested in directing this movie. What Chris knew was that Spielberg carries along more movies in the early creative phase than he could possibly make. And indeed, that was the way it was when he chose to do Lincoln. And so after two and a half years of Chris thinking about it, but working on The Dark Knight Rises, Chris came around and said, yes, I would like to direct it. So Chris took over as director. And the first half of the movie, Jonah Nolan had almost

• 3:56Speaker 02

  completely changed the story from what Linda and I began with. The second half of the movie, Chris almost completely changed the story. Though, the basic outline of going through a wormhole and visiting a black hole, and some of that was all already there in what Linda and I began with. But the human story was completely changed. This is really was the Nolan Brothers movie with the science that Linda and I began with, and additional science that came out of brainstorming between me and the two Nolan brothers.

• 4:26Ira Flatow?

  Right, right. And speaking of the science, the movie has had a huge impact, not just on the pop culture, but on science as well. Did you hope that it would open up this mind-bending world of astrophysics to the public when you were working on it?

• 4:41Speaker 02

  Well, that was my hope, yes. That was a large part of my motivation. And I feel so pleased with how effectively it did that. The number of people who have come up to me, having heard my role in this, around the world and said, "I decided I wanted to be a scientist from going to this movie." It's been a huge number of young people, and it's really been very, very satisfying.

• 5:07Ira Flatow?

  That has, that's really interesting. And you were actually involved in some official research that came out of the movie, and that was the visual depiction of the black hole. You gave the visual effects team your equations for how a black hole should behave, and you and the team published a paper on that, right?

• 5:24Speaker 02

  Right. And we actually had to develop a whole new way of doing the visualizations, different from the way that they have normally been done in the past, because black holes so radically distort light when the light goes near the black hole, that in order to get high-resolution images, it was necessary to use a whole new technique. Instead of propagating light rays past the black hole, we propagated light beams of finite size past the black hole, overlapping light beams. And that's rather more complicated, a new way to do it. And our technical paper described that, and then described some of the things

• 6:04Speaker 02

  we discovered about gravitational lensing, that is, the influence of the black hole on the light. That paper is now, I'm told, by far the most downloaded paper in the history of the journal in which we published.

• 6:18Ira Flatow?

  No kidding. If you were to, you know, with what we know about black holes in the last 10 years, would that black hole look any different today? Would your equations that you fed into the computer be any different?

• 6:31Speaker 02

  No, they wouldn't. We made a choice to that the black hole is illuminated by a disk of gas that's orbiting around the black hole, but it's a thin disk, rather like Saturn's rings. And the images you see are precisely what you would see with an IMAX camera if you were in the vicinity of that disk around the black hole. There has been since then, of course, a scientific project called the Event Horizon Telescope that takes data from radio telescopes, a number of them scattered across the world, and combines them so that you get images that are the kind of image you would normally get from a telescope that

• 7:16Speaker 02

  is as big as the Earth. And with such a big telescope, you can actually, the team that has done this made images of two black holes lighted up by gas that is not in a thin disk as we see it in the moving interstellar, but rather gas that is swirling around in three dimensions around the black holes. One of those black holes is in a nearby galaxy called M87, a giant galaxy, and the other is at the center of our own Milky Way galaxy. Those images are a little different from what you see in interstellar because the gas is behaving differently, but the similarity is quite striking.

• 7:57Ira Flatow?

  You know, when we last talked in 2014, you said there had to be a balance between established science versus speculative science in interstellar. Is there any speculative science in the movie that has been moving closer to established science since then?

• 8:17Speaker 02

  There was a speculative science in the movie as in the screenplay that Jonah Nolan was working on that has moved into the mainstream of established science. That has to do with gravitational waves. But Christopher Nolan, when he came on board, he said, look, we're not using gravitational waves very much in this movie. And there's so much other science that I'd like to add to the movie. Maybe we were better just remove the gravitational waves. So here he moved them. And so when LIGO, the project I worked on that my colleagues and I got the Nobel Prize for, when it saw gravitational waves and we announced the result, I let Chris know that

• 9:01Speaker 02

  it was going to be announced. And the day after it was announced, Chris called me up and said, would you come over to my house? Let's talk. So I went over and he spent about 90 minutes describing the wonderful things he could have done with gravitational waves if only he had kept them in the movie. And then said, well, there's no turning back time. So he went on to talk about the future movies.

• 9:27Ira Flatow?

  Did he say what he would do with them with gravitational waves?

• 9:31Speaker 02

  Not explicitly. Well, the way the gravitational waves were in the movie originally was the humans on Earth with the LIGO gravity wave detectors discover gravitational waves from a neutron star that's being torn apart by a black hole, discover those gravitational waves that have traveled through the wormhole, where the mouth of the wormhole is near Saturn. The wormhole that in the movie, then Cooper and his crew travel the other direction through to get to distant galaxy. So the gravitational waves come through the wormhole, they're seen, they're observed. And it is quite startling that the source of the gravitational waves

• 10:13Speaker 02

  is near Saturn. And that's how they discover the wormhole. So that's the way it was used originally in the movie. And there are a variety of other things could have been done with it.

• 10:26Speaker 02

  Forgotten what Chris was saying that could have been done. But the thing that is really interesting to me as a physicist, and that what I would have advocated doing with the gravitational waves is in interstellar is when two black holes collide, they actually create a storm in the fabric, in the shape of space, and the storm and the rate of flow of time. So the rate of flow of time near the black hole oscillates, it speeds up, it slows down in a crashing sort of way, like crashing waves in an ocean storm. The shape of space sloshes like crashing waves in an ocean storm.

• 11:07Speaker 02

  And it's just fantastic how wildly spacetime behaves during that collision. And I would have loved to have seen that and seen how the visual effects team dealt with that in interstellar.

• 11:24Speaker 01

  After the break, why astronomers are excited to learn more about the black hole at the center of our galaxy. Stay with us.

• 11:36Ira Flatow?

  Hi, Ira here, reminding you that Science Friday has a dollar-for-dollar donation match, which means that any donation made through December 31st will be doubled. So now is the time to head over to sciencefriday.com/support and make a gift. Our 2025 programming depends on the generosity of our fans and listeners. Again, that's sciencefriday.com/support and thanks.

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• 13:21Ira Flatow?

  Let's talk about what's happening now with astrophysics research. What has your attention right now been now with the new black hole science? Where's the interesting area here?

• 13:31Speaker 02

  Well, the remarkable thing is that now gravitational waves have now been seen by LIGO from about approximately 300 collisions of black holes. The gravity wave detectors have become more and more sophisticated and more and more sensitive, thanks to, in part, to introducing what is called quantum precision measurement. It's a cousin, basically, of quantum computing and quantum cryptography. Anyway, so the key thing then is that with this new technology, we've taken off and are seeing so many more black hole collisions than we could see before.

• 14:13Speaker 02

  In addition, gravitational waves have been discovered by a whole different technique. They've been discovered by radio astronomers who are looking at radio waves from pulsars. Pulsars are sort of like clocks, and they have a ticking that is associated with the spin of a neutron star. And if a gravity wave passes across the Earth, it may speed up or slow down those signals by influencing the radio signals as they're passing over the Earth, influencing, basically, the rate of flow of time of the clocks we use on Earth. So it's sort of like radio astronomy and optical astronomy.

• 14:58Speaker 02

  So it's really quite marvelous that we now have two different frequency bands for observing gravitational waves.

• 15:04Ira Flatow?

  You know, we talk about black holes so far away. And what about the black hole in the center of our Milky Way? Have we lost interest in that? Or is there still interest in it?

• 15:15Speaker 02

  Oh, that's a very interesting black hole. What I want there is to see a movie of the flow of gas around that black hole. Because the process by which the black hole interacts with the gas around it, we think involves magnetic fields that thread through the black hole. And as the black hole spins, it whirls the magnetic fields around. As they whirl around, they generate electric fields that accelerate particles to very high speeds. And I would like to be able to observe a movie of this flow of gas around the black hole.

• 15:56Speaker 02

  And through that movie, begin to observe this fantastic process. And in fact, the Event Horizon Telescope team is in the process of trying to make those kinds of movies. And I expect we're only a few years away from having them.

• 16:13Ira Flatow?

  This is Science Friday from WNYC Studios. You've said movie at least three times in this last sentence. Have you been bitten by the movie bug? I mean, you've been a science advisor for Carl Sagan's Contact and other Christopher Nolan films. Are you going to keep doing that kind of work? I mean, any projects you're excited about?

• 16:35Speaker 02

  Well, I had another Hollywood movie that I was working on that was conceived by Linda Oakes, my dear Hollywood friend, Stephen Hawking and me, the three of us together. About 15 years ago, we conceived it. It has never gotten fully off the ground. And tragically, Linda died a few weeks ago. And it was a huge loss in Hollywood, her death. And I suspect that movie may never in the end get made. If it doesn't get made, maybe I'll try turning it into a novel. It may still take off. But on the other hand, I'm in my mid-80s.

• 17:17Speaker 02

  I am enjoying doing different kinds of things, such as the movies. But I've not ever tried to write a novel yet. And so, yeah, so that would be what I may do with this.

• 17:31Ira Flatow?

  Tell me how the fame from these movies has affected your career besides thinking about being a novelist now.

• 17:37Speaker 02

  Well, it means that I get several requests to lecture somewhere online a day, and I say no to almost all of them. And that's how it's affected my life. I'm very self-protective. I love the creative process. I just published with a wonderful painter, Thea Halloran, about a year ago, a book of her paintings and my poetry. And so I'm just having great fun being creative in ways that I never imagined I'd be creative. I realized that the whole purpose of the Nobel Prize from the point of view of the Nobel Committee

• 18:18Speaker 02

  is to create icons who can promote science. And so I have, as an icon, I feel uncomfortable as an icon, but I have sort of come to terms with it. I feel some obligation to help promote science, but only to the extent that it doesn't get seriously in the way of continuing to do creative work, but of new types.

• 18:40Ira Flatow?

  Do you think science needs a little more promotion now, that it seems to be under attack in many fields?

• 18:46Speaker 02

  Yes, this is a particularly scary time, I think, when we see a man being pushed to become the Secretary of Health and Human Services, who promotes the idea that vaccines are dangerous, when the science says that's simply not true. It's really a scary time for the human race and for the dangers that can come as a result of not paying attention to science. So, yes, I worry a lot about that in this era.

• 19:21Ira Flatow?

  Well, I'm glad you're not worrying too much to talk with us and to be optimistic about the future. It sounds like you still are.

• 19:29Speaker 02

  I am, I am.

• 19:31Ira Flatow?

  Yeah. Dr. Thorne, thank you for your work, for your career, and everything you've given us. And we hope to have you back on the show not quite 10 years from now again.

• 19:41Speaker 02

  Okay, well, thank you. And try to remember to call me Kip.

• 19:45Ira Flatow?

  Okay, Kip.

• 19:46Speaker 02

  Thank you, Ira.

• 19:48Ira Flatow?

  You're welcome. Dr. Kip Thorne, professor of theoretical physics at Cal Tech.

• 19:55Speaker 01

  That's it for today's episode. Tomorrow, NASA's Parker Solar Probe is getting closer to the sun than any other human-made object. Join us tomorrow for the how and the why. Lots of folks help make the show happen, including

• 20:10Speaker 05

  Dee Petersman.

• 20:11Speaker 01

  Sandy Roberts.

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  Beth Ramey.

• 20:13Speaker 05

  John Dankoski.

• 20:14Speaker 01

  I'm Sci-Fry producer Kathleen Davis. Thanks for listening.