Tag Archives: Luminet

40 Years of Black Hole Imaging (2): Colors and movies, 1989-1993

Sequel of the previous post 40 Years of Black Hole Imaging (1)

First Flight into a Black Hole

In 1989-1990, while I spent one year as a research visitor at the University of California, Berkeley, my former collaborator at Paris-Meudon Observatory, Jean-Alain Marck, both an expert in general relativity and computer programming, started to extend my simulation of 1979. The fast improvement of computers and visualization software (he used a DEC-VAX 8600 machine) allowed him to add colors and motions. To reduce the computing time, Marck developed a new method for calculating the  geodesics in Schwarzschild space-time, published only several years later (Marck 1996). In a first step Marck started from my model of 1979 and calculated static images of an accretion disk around a Schwarzschild black hole according to various angles of view, see Figure 1 below.

Figure  1. False-Coloured images of a black hole accretion disk for various angles of view by J.-A.
Marck &  J.-P. Luminet , 1989 (unpublished).

In 1991, when I went back to Paris Observatory, I started the project for the French-German TV channel Arte of a full-length, pedagogical movie about general relativity (Delesalle et al. 1994). As the final sequence dealt with black holes, I asked Marck to introduce motion of the observer with the camera moving around close to the disk, as well as to include higher-order lensed images and background stellar skies in order to make the pictures as realistic as possible. The calculation was done along an elliptic trajectory around a Schwarzschild black hole crossing several times the plane of a thin accretion disk and suffering a strong relativistic precession effect (i.e. rotation of its great axis), see figure 2 below.

Compared to my static, black-and-white simulation of 1979, the snapshot reproduced in Figure 3 below shows spectacular improvements:

Figure 3. Colored image of a black hole accretion disk as seen by a moving observer at 7°
above the disk’s plane. The observer uses a camera equipped with filters to convert into
optical radiation the emitted electromagnetic radiation. The arbitrary coloring encodes the
apparent luminosity of the disk, the brightest and warmest parts being colored yellow, the
colder parts red. The transparency of the disk was enhanced in order to show the secondary
image through the primary, as well as some background stars. Compared with figure 8 there
are additional distortions and asymmetries due to the Doppler effect induced by the motion of
the observer himself. As a result the region of maximum luminosity has no more the shape of a
crescent (from Marck 1991)

The full movie is  available on my youtube channel :

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An Approach to Infinity

Like the Italian artist and engraver Giovanni Battista Piranesi (1720-1778), whose follower he is, Jean-Pierre Luminet depicts space with passion and melancholy. By repeating ceaselessly black and white checkerboards, he evokes the notion of infinity and generates the dizziness of the glance. By disrupting the laws of classical perspective, he conjugates architectural immobility and time unsettledness. The artist immerses elements in a black ocean, and such a subtle interaction gives the sensation of perpetual time. Infinity is that aspiration felt by the man held on ground by gravitation. Jean-Pierre Luminet depicts this sensation by creating vanishing points towards which one feels irresistibly attracted.

Anne de Commines, Art critics

The Cosmos As A Poem

As an astrophysicist and a poet, I am apparently well-prepared to talk about cosmic poetry. However it is not so obvious. During many years I conducted these two activities quite independently – I mean scientific investigation of the nature of the universe through the study of relativity, black holes, cosmology, topology, and poetic writing. I even refuted any relationship between these two ways of apprehending the world.

I began to publish poetry 30 years ago, at the same epoch when I also published my first scientific works, however my poetic works had nothing to do with astronomy. For me, poetry had to express feelings, emotions, and subjects that cannot not be reached by rational investigation, such as love, death, beauty, loneliness, despair, and so on.

Griph NoirSoleil
Iti lanature

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Black Hole Imaging (1/3): Back to the basics

The centre of the black hearth,
of setting suns on the shore :
ah ! well of magic
Arthur Rimbaud (Illuminations)

As probably all of you already know, the Interstellar movie tells the adventures of a group of explorers who use a wormhole to cross intergalactic distances and find potentially habitable exoplanets to colonize. For the scientific part, the film director, Christopher Nolan has collaborated with a colleague of mine, the famous physicist Kip Thorne, a specialist in general relativity and black hole theory.

With such a scientific consultant, the promotion of the movie insisted a lot on the realism of the black hole images calculated by Kip Thorne and the team of visual effects company Double Negative. The most striking one shows a glowing accretion disk appearing above, below  and in front of the black hole.

The simulation of a black hole with thin accretion disk as shown in the Interstellar movie

As soon as the movie was displayed on the screens, a lot of physics blogs have commented in details the “Science of Interstellar”. Kip Thorne himself has published a such entitled popular book, to explain how he tried to respect scientific accuracy despite the sometimes odd demands of Christopher Nolan, ensuring in particular that the depictions of black holes and relativistic effects were as accurate as possible.

destinSince, as soon as 1979, I was the first researcher to perfom numerical calculations and publish the simulated image of a black hole surrounded by a thin accretion disk (you can upload the technical article here), to inaugurate this new blog I’ll devote a series of 3 posts to the basics of black hole imaging. A good part is adapted from a chapter of one of my books, published in French in 2006, Le destin de l’univers – unfortunately not yet available in English. Continue reading

Luminet’s Illuminations

Luminet’s reinstated visualization of a finite Universe, albeit one from which we can exit through one face and simultaneously enter through the opposite one, relies upon a keplerian form of mental sculpture that may be described as plastic rather than algebraic. Luminet’s characteristic lithograph, Big Bang, exploits the spatial vocabulary of perspective to evoke realms beyond the three dimensional. Whereas Escher relied on contradictions and oscillating ambiguity in his graphic art, Luminet suggests plunging, interpenetrating and matter organizes itself into structures on the right; the tumbling dice on the left imply irreversible disorganization arising from chance. The remarkable range of Luminet’s creativity in art and science is integral to his agenda to recreate what he calls a « humanism of knowledge » — not that the arts and sciences are somehow to be conflated, because they work in very different ways, with illogical and logical means. But Luminet argues that they well up from the same instincts and intuitions: « I do not believe that we acquire at the beginning the ‘heart of an artist’ or the ‘heart of a scientist’. There is simply within oneself a single devouring curiosity about the world. This curiosity pushes us to explore it through various languages and modes of expression, » he says.

Martin Kemp, professor of the history of art at the University of Oxford. Excerpt from “Luminet’s Illuminations : Cosmological Modelling and the Art of Intuition”, Nature, 20 november 2003, vol. 426, p. 232