Special effects or reality?
The software used to create images of the black hole in the last film by Christopher Nolan is so effective that it has given us the most detailed vision that could experience a person, if it could orbit around this extreme object.
The team in charge of the special effects of the film by Christopher Nolan “Interstellar” brought science fiction in science, providing new and important knowledge on the behavior of black holes, so mysterious and fascinating objects.
In an article published these days in the Classical and Quantum Gravity, journal the team describes the innovative programming code that was used to create images of the wormhole (a kind of tunnel in the fabric of space and time), the black hole and other objects celestial, and explains how this code has led to new scientific discoveries.
Interstellar interstellar_wormhole2Il team is formed by the staff of Double Negative, a visual effects company in London, and theoretical physicist Kip Thorne of Caltech. This team, using their own code, has studied the case of a camera should take pictures near a black hole. The team noted that when the light is at a close distance from a black hole in rotation, generates surfaces extremely peculiar space, called caustic, a result of the envelope of light rays on surfaces with different curvatures. When a room is located near a region of space of this type, see create dozens of images of individual stars and the thin plane of the galaxy along where the black hole. The team’s discovery of Interstellar is that these images are concentrated along the event horizon, the physical limit beyond which nothing can escape the gravitational pull of the black hole.
These multiple images are caused by the drag of the black hole in space, in a swirling motion which implies a continuous deformation of caustics. It is the first time that we can simulate the behavior of caustics for a room that is near a black hole, and the resulting images give a good idea of what we might see if a person could object to this extreme orbit.
The discovery was made possible thanks to the programming code written by the team, which – as the article explains – has mapped trajectories of millions of light rays by studying the evolution of their form as they passed near the spacetime deformed by the presence of black hole. The programming code was used to create images of the wormhole, the black hole, called Gargantua, and its accretion disk, which reveal unprecedented accuracy.
These pictures showed portions of the accretion disk that moved above and below the event horizon of Gargantua, and along its equator, producing an image that has become symbolic for the film.
This strange distortion of the disc is caused by the effect of gravitational lensing, a process through which the light, starting from different trajectories of the disc or from distant stars, is concentrated, diverted and distorted by the black hole, and then comes to the simulated room. The effect of gravitational lensing is because the black hole creates a gravitational field extremely intense, folding the fabric of space-time itself, as would a billiard ball resting on a stretched sheet.
In the early stages of their work for the film, when they were treating the case of a black hole surrounded by a large group of distant stars and nebulae, rather than from an accretion disk, the team discovered that the standard approach, with ‘use of a single ray of light per pixel (in the case of an image IMAX, a total of 23 million pixels), resulted in a flicker of stars and nebulae in motion on the screen.
Oliver James, co-author of the study and a scientist at Double Negative, said: “To eliminate flicker and get clean images realistically, we have modified the code in a way never before experienced. Instead of tracing the path of a single ray of light using Einstein’s equations, we have traced the paths distorted by light beams. ”
Kip Thorne, co-author of the study, added: “This new approach will be of great help to us astrophysicists: we also need to clean images.” This is echoed by Oliver James “Once our code, called DNGR (Double Negative Gravitational Renderer) has become solid and allowed us to create the images you see in the film Interstellar, we realized we had built an instrument easily adaptable to scientific research ».
In their article, the authors report how they have used the code DNGR to produce a number of simulations that explore the effect of caustics, the peculiar surfaces “crumpled” space, the stars distant views of a double post near a black hole in rotation. “A ray of light emitted from any point of a caustic surface is focused by the black hole in a bright cusp,” says James. “All these cusps envelop the sky on itself many times when the room is close to the black hole. This winding of the sky is caused by the rotation of the black hole, which drags the space in a swirling motion on itself as the air inside of a tornado, and distorts repeatedly caustics around the black hole. “