Interstellar visual effects model generates realistic image of black hole

Cosmos Magazine


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We previously discussed the mathematics behind the stunning images in Christopher Nolan’s Oscar-nominated space epic, Interstellar.

Now, the visual effects team behind the movie have published a paper about the model they created in order to provide new insights into the effects of black holes on space.

Blakc hole2
An example of caustics produced by a glass of water. An optical caustic is the two-dimensional projection of an envelope of light rays refracted by a 3-dimensional curved surface or object. Caustics in space are surfaces that form similar patterns, produced by a black hole’s spacetime curvature.
Heiner Otterstedt

The team’s unique computer code, called Double Negative Gravitational Renderer (DNGR), generates images by modelling the path of light as it is warped by the gravity of a black hole.

Using this code, the Interstellar team found that when a camera comes close to a rapidly spinning black hole, certain strange surfaces in space, called caustics (see below image), create multiple images of individual stars and of the thin, bright plane of the galaxy in which the black hole lives. 

These images were formed by the black hole dragging space into a ‘whirling motion’, and dragging the caustics around itself many times. This resulted in a correlation of images that give us some idea of what we would see if we were orbiting around a black hole. 

The video below explains this process in more detail:

[Credit: Classical and Quantam Gravity, 2015. Reproduced by permission of IOP Publishing]

Co-author of the study Oliver James, said: “To get rid of the flickering and produce realistically smooth pictures for the movie, we changed our code in a manner that has never been done before. Instead of tracing the paths of individual light rays using Einstein’s equations–one per pixel–we traced the distorted paths and shapes of light beams.”

According to James, the method employed by the Interstellar team has implications for use in scientific research, turning science fiction into science fact.

“Once our code was mature and creating the images you see in the movie… we realised we had a tool that could easily be adapted for scientific research.” 

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