In what has got to be one of the highest level fix-ups of all time, in 1980, astronomer Carl Sagan fixed up his friend, physicist Kip Thorne, with movie producer Lynda Obst.
The match wasn't as strange as you might think, Obst had formerly been the Counterculture-and-Science Editor for The New York Times Magazine. Thorne was the Feynman Professor of Theoretical Physics at the California Institute of Technology.
While the match didn't take, Obst and Thorne remained friends. In 2005, they met for a dinner where Obst outlined to Thorne her idea for a science fiction movie that involved wormholes, black holes, multiple dimensions and most of all, the effects of gravity and speed on spacetime.
To become involved with the film, Thorne had two requirements:
1. That nothing in the film violate the laws of physics or our knowledge of the universe.
2. That anything speculative in the movie arises from real science.
In 2006, no less a personage than Steven Spielberg signed on to direct the film, which became known as "Interstellar". The screenwriting was assigned to Jonathan Nolan, who is probably most well-known for creating the TV series "Westworld".
By 2007, Spielberg was out, having been unable to reach an agreement with the studio responsible for the project – Paramount. Instead, directing duties for the movie went to Christopher Nolan, Jonathan's brother.
Massive objects cause a distortion in spacetime
At its core, what "Interstellar" is about is time, and how time relates to the people we love. According to Einstein's Theory of General Relativity, we don't all experience time the same way, instead, time depends on where we are in the universe and what we are doing.
The biggest disrupters of time are speed and gravity. Travel close to the speed of light, and time slows down. Tread close to a black hole and its colossal gravitation, and time really slows down. If the time has slowed down for you, it hasn't slowed down for those we love back home somewhere, and this creates the conundrum at the heart of "Interstellar".
Black holes had shown up in movies before: 1997's "Event Horizon", 2005's "Zathura", and 2006's "The Black Hole," but none was portrayed very realistically. A team at the firm Double Negative VFX (visual effects) was tasked with creating Gargantua, the spinning black hole at the heart of "Interstellar". As they worked, Kip Thorne sent them detailed scientific papers that described the physical phenomena that occur at and around a black hole.
The group at Double Negative created an entirely new piece of software, called the Double Negative Gravitational Renderer (DNGR), in order to solve the equations for ray-bundle (light-beam) propagation through the curved spacetime of a spinning black hole. What resulted was far from the all-black black hole, Gargantua was surrounded by disks of light. An accretion disk, a belt of gas that orbits a black hole and gathers heat through friction, glowed brightly around its middle.
Other rings of light around Gargantua were created by gravitational lensing. This is where a massive body warps the spacetime around it, altering the path of light coming from bodies behind it. That light can be so warped that it ends up orbiting around a black hole. Thorne said, "...I worked out the equations that would enable tracing of light rays as they traveled through a wormhole or around a black hole so what you see is based on Einstein's general relativity equations."
New phenomena were discovered
The resolution of the rendering software was so high that team members were able to examine the area just outside of the event horizon. An event horizon is a region in spacetime beyond which events occurring within a black hole cannot affect an outside observer, it is the boundary at which the gravitational pull of a massive object is so great that nothing, including light, can escape it.
Because Gargantua was spinning at almost the speed of light, DNGR showed that spacetime warped into shapes never seen before. This led to the publication of scientific papers on the effect.
With Thorne credited as an executive producer, "Interstellar" went on to earn $700 million worldwide, and Game of Thrones writer George R.R. Martin called it "the most ambitious and challenging science fiction film since Kubrick's 2001." Double Negative went on to win the 2014 Oscar for Best Visual Effects.
In 2014, Thorne released a book entitled, "The Science of Interstellar," which described not only the science behind the film, but his experiences working on it.