From physics to Hollywood – the Black Hole that became a film star

It’s reasonable to say that Kip Thorne’s career route has not been that of your typical theoretical physicist. After retirement from his role as Feynman Professor of Theoretical Physics at the California Institute of Technology (Caltech) in 2009, his passion for education burned on. Taking a step back from mentoring and advising students, Thorne turned his efforts towards the public, with the intention of illuminating the darkest corners of Einstein’s general theory of relativity: black holes.

Lying at the fringes of known physics, even the simplest concepts concerning black holes are unintuitive and mind bending (even to final year physics students), yet it was these that Thorne set out to expose. With cinema as his chosen forum, Thorne approached film producer Lynda Obst and they started developing ideas for a movie revolving around black holes and wormholes (theoretical structures tunnelling through space to join two distant regions).

After initial interest from Steven Spielberg, the film was eventually picked up by director Christopher Nolan, known for producing stunning visuals in titles such as Inception and The Dark Knight.  Christopher set out to combine his ideas with a script his brother, Jonathan Nolan, had developed for in 2007 for Obst in a separate venture. He then enlisted the help of Thorne, whose works inspired the film, as both an executive producer and scientific consultant for the developing film.

The finished product, Interstellar, follows a group of explorers and scientists attempting to save humanity from an environmentally ravaged earth. Smashing through the boundaries of known space travel, they venture into a wormhole in an effort to discover a habitable planet in a new galaxy.

Upon seeing the potential for a successful film, Nolan set Thorne the task of accurately depicting Gargantua, the black hole rotating at close to the speed of light, central in the plot of the film.  Thorne not only had to formulate the spatial geometry created by the immense structure, but also devise a way to illuminate the region surrounding a black hole’s invisible interior. Luckily, Thorne’s passion for physical accuracy in nature provided the answer.

Before falling into the inescapable depths of a black hole, matter – be it a neighbouring star or planet, is ripped apart and forms a flat circulating ring around the black holes centre (similar in shape to those surrounding the planet Saturn). When the black hole encounters a lot of matter to feed upon, these rings – known as accretion disks – can themselves reach a colossal size. Heated by friction as they grow, they can form some of the brightest structures in the universe, juxtaposing the darkness lying within their disks.

Working together with the special effect house Double Negative, Thorne set out to produce images of Gargantua fitting of a Nolan movie. After devising a whole new set of equations that would work within Double Negative’s rendering software, Thorne left the special effects team to run the simulation and produce the images of the black hole and surrounding accretion disk.

Theoretical physicist Kip Thorne runs through some equations on a blackboard with 'Interstellar' actress Jessica Chastain. © Paramount
Theoretical physicist Kip Thorne runs through some equations on a blackboard with ‘Interstellar’ actress Jessica Chastain. © Paramount

What the special effects team saw next was truly surprising. Instead of the flat disk they expected to see they had created an astonishing glowing halo stemming from the disk and surrounding the black hole. The team, unable to explain the phenomenon turned to Thorne for answers.  Although unexpected, Thorne recognized that the beautiful structure came directly from the equations he had supplied. It transpired that the black hole’s immense gravity, coupled with its rapid rotation, actually meant that the very fabric of the universe was being dragged along with it as it spun on its axis. This warped the surrounding space in such a way that light from the originally flat rings had become wrapped around the black hole, forming the distinctive halo.

What the team had therefore created was an image of a black hole to unprecedented physical accuracy.  Taking up to 100 hours to render a single frame, the simulation was so accurate that Thorne is now planning on using it as observational data in multiple scientific papers detailing the discovery of the halo.

The end result therefore leaves everyone satisfied. Nolan gets a truly breath-taking backdrop in which to tell his story, and Thorne can rest easy in the knowledge that Einstein’s iconic theory of general relativity has been bought to the big screen in a manner that will leave viewers awestruck and wanting more.

Starring Matthew McConaughey, Anne Hathaway, Jessica Chastain and Michael Caine, Interstellar will be hitting UK cinema screens on 7th November.

Henry Munro

Feature Image: Wired

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