The Rogues' Gallery

Black Hole In Movie Interstellar Is Most Accurate Ever In Any Movie

Bob Novella October 28, 2014 6 Comments

The new movie Interstellar not only promises to be a top-notch science-fiction movie, it may have actually advanced our understanding of black holes.

This came as quite a wonderful shock to me. All too often, scientific accuracy in the movies takes a back seat or even a trunk seat to such considerations as plot development, dazzling eye-candy etc. Often, movie-makers are not even aware that real science is often more amazing than the lame made-up ideas they come up with.

This is one of the reasons that I will always appreciate director, screenwriter, and producer Chris Nolan. You have almost certainly seen some of his films which is a very safe prognostication considering that list includes the likes of Memento, Inception, and of course, The Batman Dark Knight trilogy. Describing the reason for scientific accuracy in Interstellar Nolan said this:

“The initial impetus for the project had been to say why not examine real possibilities, why not actually look at the real science there”

Why not indeed.

The genesis of that thought occurred when Chris joined the movie project and starting re-writing the script that his brother Jonathan had written. The gist of the movie involves a dystopian future in which humanity is at the brink of extinction due to global GMO crop failures (I made the GMO part up). Matthew McConaughey’s erstwhile astronaut character is ushered out of retirement to make a bold attempt at finding another solar system that the rag-tag remnants of homo-sapiens could migrate to.

Science is clearly an integral component of this movie and Nolan wanted to properly wrap his head around it. To do so he started having talks with theoretical astro-physicist Kip Thorne. Kip was more than qualified to be the scientific advisor for the movie having been the The Feynman Professor of theoretical Physics at Caltech and a prominent expert at determining the implications for astrophysical phenomena of Einstein’s General Relativity.

Due to various plot developments, the movie required time dilation to occur so that different characters could experience the flow of time at significantly different rates relative to each other. Kip of course suggested a black hole to pull that off (relativistic velocities would also suffice btw). For this specific plot element, Nolan asked Paul Franklin, senior supervisor of the Academy Award-winning special effects house Double Negative, to work with Kip to create the black hole. Franklin was an excellent choice not only for his obvious talent but since he clearly shared Nolan’s love of scientific accuracy. I say that because Franklin said this:

“Science fiction always wants to dress things up, like it’s never happy with the ordinary universe”

He hit the nail on the head with that one.

Thorne’s light distortion diagram

Kip could at that point have just given Frankin some ideas how to accurately represent a black hole. Instead he gave him page after page of equations that could be fed into a rendering program. The problem was, no renderer they had could use them because the ray-tracing algorithms they employed to build up images and reflections are based on light traveling in straight lines. Into order to deal with the curved paths of light from gravitational lensing around a black hole the team had to write a whole new renderer.

Once they were ready it was time to render the images based on Kip’s equations….and render they did. Some images were so number-crunchy that it took 100 hours to create just one. After 30 people and thousands of computers toiled for a year they finally had the 800 terabyte result. When the team looked at what they had wrought though, they thought there was a bug in the program. When Kip looked at it though he said:

“Why, of course. That’s what it would do.”

What they saw was the most accurate portrayal of a black hole in cinema ever. It was different enough from expectation that even Kip said he never would have expected it. The images showed that the light emitted from the accretion disk of swirling matter orbiting the black hole would have its light gravitationally distorted such that a halo of light appeared not only above and below but also in a line in front of it as well. This lensing of light has been used for years to see distant background objects like galaxies but now we were seeing what that lensing does to the light generated nearby the black hole as well.

So, not only has a science fiction movie been instrumental in advancing scientific research, the icing on the cake is that Kip thinks he should be able to get a couple bona-fide papers out of it as well. One for the astrophysics community and one for the special effects community.  Like any advances in science, I’m curious to see what peer review has to say about his results. I was actually bummed a bit when I came across a comment about this news item which said that we’ve had accurate scientific representations of accretion disk black holes for a while now even if we’ve not had accurate cinematic representations of them. On the other hand Kip Thorne seemed genuinely surprised at what his equations produced and if anyone is aware of this topic he’d be the guy.

Regardless how this plays out, I hope other movie makers take note that it makes sense to integrate real science into movies as often as possible, if for no other reason that it could get you tons of  free publicity ( and maybe a scientific paper)

Video: Science of the Movie

Press Release

Movie Trailer

Image Credit: Paramount