A Tale of Two Black Holes

Black Holes are one of the most incomprehensible and intriguing phenomena in the Universe. A singularity at which matter becomes infinitely dense, where time and space break down, and from which not even light can escape, they were identified as a possible solution to Einstein’s Theory of General Relativity as early as 1916 but didn’t acquire their now-common name until the 1960s. The detection of supernovae and advances in stellar theory made it clear that black holes were the likely end-state of massive stars, although the implied breakdown of conventional physics was resisted by prominent stellar physicists. By the late 1960s, though, the existence of black holes became general knowledge, driven in part by the realisation that many of the X-ray and radio sources seen by new instrumentation could only be explained by material falling into these cosmic whirlpools. Identified in 1971, the Milky Way X-Ray source Cygnus-X1 became the first object widely accepted by the astronomical community as a stellar-mass black hole.

Black holes appear frequently throughout science fiction, and I’ll likely come back to other examples in future posts, but for the moment I want to look at just two examples, The Black Hole and Interstellar, both blockbuster films of their day, and look at the changing representation of black holes over time.

[Note: some unavoidable spoilers ahead!]

The Black Hole

Released in December 1979, The Black Hole was a blockbuster movie, with a script by Gerry Day and Jeb Rosebook, direction by Gary Nelson and furnished with a sweeping score by John Barry. Produced by the Disney studios, it took heavy inspiration from their earlier successful film 20,000 League Under the Sea (1954, dir: Fleischer), as well as from the science fiction boom driven by 2001: A Space Odyssey (1969, dir: Kubrick) and Star Wars (1977, dir: Lucas). Achieving a then-record breaking opening weekend, and overall modest commercial success [1], the film was heavily merchandised, was one of the first of Disney’s productions to be released on home video, and was frequent bank-holiday fare on television throughout the 1980s. It has since become something of a cult classic on DVD, blu-ray and download.

[Image: Film poster for The Black Hole, from Starburst Magazine, December 1979. Image source: archive.org]

The film centres on the crew of an exploratory spaceship, the Palomino, which is formed of two scientists, a journalist, two crew and a small multipurpose robot (something of an inevitability in the wake of Star Wars, although in an interview for Starburst magazine (May 1980) the production designer and director noted that they were well into production by the time Star Wars came out and it wasn’t an influence). Passing by a black hole, they discover another ship, the USS Cygnus (named for the then-known black hole candidate Cygnus X-1), which was lost twenty years before, parked in an apparently-impossible orbit close to its event horizon. Swinging past to investigate, the Palomino is unable to break away and is forced to seek shelter in the incomprehensible area of null gravity surrounding the Cygnus. Boarding the much larger ship, the Palomino personnel find it populated by robots (both clearly mechanical and humanoid) and eventually find the sole survivor of its original crew: genius scientist and ship’s captain, Hans Reinhardt. Although Reinhardt is keen to assist their repairs and hurry them on their way, he is also interested in having them monitor his planned climactic mission: a dive into the black hole, protected by Reinhardt’s innovative anti-gravity field.

However the Palomino group’s suspicions are raised, and they eventually realise that Reinhardt’s account of his crew’s demise is less than truthful, and that their own lives are in danger. Their attempt to escape is complicated by robots, spaceship problems and inexplicably fiery meteors, and they eventually find themselves locked onto a path through the black hole, as does an injured Reinhardt and his chief robot Maximillian. Passing through visions of heaven and hell during the passage, the surviving Palomino crew eventually emerge back into normal space.

The black hole that forms the backdrop for the entire film is presented primarily as the object of Reinhardt’s obsession, rather than scientifically. In the narrative, it is discussed often in terms of biblical and allusional language about the mind of god and knowing the unknowable, rather than in terms of time-space distortion or general relativity (GR). While the existence of an Einstein-Rosen bridge (a solution to GR that provides the foundation for the concept of wormholes linking two black holes) is mentioned as a possibility in passing, it is not explained or explored any further. Indeed, most of the discussion (implicit and explicit) in the script hinges on the nature of humanity and human reactions to the unknown. The black hole is nonetheless illustrated as a whirlpool of swirling gas, heading into the central dark point, which is steadily drawing material towards it. As the artists realised, a black hole itself is invisible, with any striking visuals mostly coming from gas heated during its infall. This was realised through extensive use of detailed matte paintings and colour separation overlay filming.

As Disney’s first overtly science fiction (or at least space-opera) blockbuster The Black Hole attracted considerable press coverage and marketing efforts. The film received mixed reviews in the mainstream press, detailed discussions of the entirely novel computer graphics, automated camera control systems and special effects in the film press and was generally praised for its effects but panned for everything else in the science fiction genre press. Science fiction magazine reviews (as well as criticising the cute robots and hoary space-opera tropes) tended to focus on the scientific inaccuracies in the film [2], including its failure to address spaghettification (death by extreme tidal forces) or time dilation (a consequence of bending space with a black hole is bending time), as well as the convenient invention of anti-gravity by an obsessive genius [3]. A comment that the mission of the Palomino was “to search for habitable life” was greeted with understandable head scratching. Public-facing scientific periodicals (e.g. Nature, Scientific American etc) and most large newspapers appear to have largely ignored the film. More recently, science populariser Neil de Grasse Tyson has highlighted The Black Hole as “the most scientifically inaccurate film ever” (a bold and probably unfair claim!) on the basis of its use of quasi-religious imagery for the interior of the black hole itself.

This failure of the scientific community to engage with a science fictional opportunity is interesting, especially as it appears to have been one-sided. Disney already employed former Mercury astronaut Gordon Cooper as a consultant on their theme parks, and he became closely involved with the film as a technical advisor. As an astronaut, he was able to comment authoritatively on the spacecraft, but his input on astronomical matters may have been less robust. Interviews with the creative staff also describes them reading extensively from contemporary scientific literature, and visiting the NASA Jet Propulsion Laboratory [4]. As art director John Mansbridge commented in a lengthy article in Cinefantastique magazine:

“So about five years ago we all went to the Jet Propulsion Laboratory for an interview with a Dr. Millikin there. who seemed to be in charge of the place. We asked him and his assistants a lot of technical questions, and he told us what was possible or impossible for what we had in mind. Black holes being what they are, an unknown quantity, got them very excited about the whole thing. They were quite enthusiastic.”

[Images: Excerpts from the Press pack for the Black Hole from Disney studios. Photograph of own copy.]

What is more, the press materials released by Disney appear to have been keen to play up the scientific aspects - the press pack issued to cinemas suggested they team up with local planetariums, observatories, schools and colleges to promote the film, while other press materials presented an explanation of black holes based on physicist John Wheeler’s earlier discussion in Time Magazine in 1973. Unfortunately most of the press coverage appears to have ignored this attempt to establish scientific authenticity entirely - as far as I’ve been able to find, only the American Cinematographer journal spared more than a line or two for the science of black holes in its extensive coverage of the film. (If anyone's aware of examples of planetariums and observatories reciprocating do please let me know!)

Ultimately, despite the apparent disdain of scientists and science fiction reviewers, the film is remembered for its then-impressive special effects, including swirling, whirlpool-like imagery for the black hole itself, and an entirely novel automatic camera control system. It is known for its sweeping score, and was one of the last films to be released with an orchestral overture preceding the first images. It’s also not been without its legacy. The Black Hole introduced many members of the general public to the eponymous objects, and in 2014 multimedia science popularisor Symphony of Science used a scene from the film as an introduction to its excellent track Monsters of the Cosmos [5].

Interstellar

Released in 2014, the blockbuster movie Interstellar, directed by Christopher Nolan, and written by Christopher and Jonathan Nolan, also focussed on human nature through the context of a massive black hole. This narrative focussed on a retired astronaut living on a near-future Earth ravaged by environmental collapse and a blight of food crops. As a desperate last effort to find a future for a humanity doomed to extinction, the remnants of NASA launch a mission through a newly-discovered stable wormhole near the orbit of Saturn. This leads to a system of three potentially-habitable worlds which orbit close to a supermassive black hole dubbed Gargantua. Visiting the surfaces of these worlds in an increasingly desperate search results in various levels of time dilation relative to Earth and colleagues in orbit. Eventually, the protagonist journeys into the event horizon of Gargantua, passing through a transcendent experience which reconnects him with his long-lost daughter.

The film was a much stronger commercial and critical success than its predecessor, and there are some interesting comparisons between the two. Like The Black Hole, Interstellar involves a journey first around and then into a wormhole. Both benefitted from epic orchestral scoring, in the case of Interstellar by Hans Zimmer. Also like The Black Hole, it was nominated for an Academy Award for Best Visual Effects, in this case winning and so recognising the innovative computer-generated visuals and techniques involved. Friendly robots also form part of the mission personnel in both films, although in Interstellar they are geometric forms, lacking the anthropomorphic features of robots in The Black Hole.

A striking difference between the films lies in their visual representation of the central black hole. Instead of the matte whirlpool paintings of The Black Hole, Interstellar’s black holes presented a less expected appearance.

As early as 1979 (the year of The Black Hole’s release!), astrophysicist Jean-Pierre Luminet had calculated the likely visual appearance of a black hole’s accretion disk complete with the asymmetry and distortions caused by the bending of light in gravitational fields, based on a demanding computer simulation. Interstellar went further. Renowned black hole physicist Kip Thorne (who soon afterwards won the Nobel Prize for his work on gravitational waves) used the much, much more powerful computer mainframes of 2014 to extend these calculations, producing scientifically-driven visualisations and using ray-tracing technology to enable a virtual camera to look down the throat of a wormhole and reproduce the distorted images that might be visible to a human in that position. These visualisations not only appeared in the film, but also drove scientific research papers and popular articles written by Thorne and others, and were extensively discussed in Thorne’s tie-in popular science book The Science of Interstellar. Thorne’s involvement in the creative process wasn’t an afterthought. Key scientific elements of the plot apparently originated in a treatment co-written by Thorne himself, before being blended with more character driven narratives by the Nolans.

The resulting visualisation of a black hole accretion disk differs significantly from the older whirlpool imagery. Instead of the disk being seen face on, it is viewed from the side, with the glow of hot gas silhouetted against the darkness. More memorably still, the effects of gravitational bending of light results in the far side of the disk also being visible, projected to lie above and below the central singularity. The relative motion of the two sides further results in the upper image of the arc being more luminous than the bottom. First appearing in Interstellar, this visual iconography for a black hole has now become ubiquitous in science fiction, appearing prominently in the Star Trek universe (e.g. Discovery, Lower Decks), as well as many other examples.

While Thorne and others noted that the relativistic Doppler effect would also alter the colour of the disk, the idea of a complex web of yellow arcs encasing a black hole, bent into surprising shapes by the distortion of gravity, is now part of the popular imaginary. In addition, the film went to some lengths to present key concepts of general relativity, time dilation and black holes - albeit briefly and using the astronaut protagonist as an everyman character to whom such matters need to be explained.

Also very different from the reception of The Black Hole in 1979 is the extent to which Interstellar was discussed in scientific literature. Reviews appeared in Nature, Nature Physics, New Scientist, Scientific American and Physics World (monthly magazine of the UK Institute of Physics) amongst others. While these often commented on the sentimentality of the characters’ plot arc and the incomprehensibility of the closing sequences, they were generally complementary regarding the physics representation - and the fact that such an effort had been made to represent accurate physics in the first place. Not only did Thorne’s popular book The Science of Interstellar attempt to explain the science of the film at an accessible level but more detailed analyses appeared aimed at a scientific audience, including one by Luminet (who had made his own theoretical black hole image in 1979), and the film featured in frequent public outreach talks (including one I developed myself) by astronomers. The film was also promoted by Google with lesson plans made available as part of its educational strand [6], and inspired educational pieces on other online platforms such as Ted-Ed.

This wholesale embracing of the film by the scientific community as a tool for education and science communication is in marked contrast to the response to The Black Hole. In part this is likely due to the connectively enabled by modern telecommunications, which enabled material to be shared and communicated more effectively over the internet, and also increased the reach of science communicators. It is also more than likely that at least some of the activity which did occur in 1979 was simply not captured in archived newspapers and media information.

However it likely also represents how the relationship between science and science fiction has evolved. In the late 1970s and early 1980s, movies such as Star Wars and Alien, and television series such as Battlestar Galactica or Buck Rogers in the 25th Century were the highest profile science fiction in the public mind and built on the space operas and monster movies of earlier decades. Serious science fictional themes were common in novels and periodicals, and certainly appeared in movies such as Stanley Kubrick’s 2001: A Space Odyssey (1969) and the earlier Forbidden Planet (1956, dir: Wilcox), but neither Disney’s history of animated movies, nor its swashbuckling pseudo-Victorian scientific romances such as Twenty Thousand Leagues Under the Sea would have led to much confidence that it would deal with the subject with scientific seriousness. As such, professional astronomers might have wished to distance themselves from a genre associated in the public mind with melodramatic fantasy. The frequent use of religious imagery and terminology in the film screenplay likely also discouraged engagement from reputable scientists. 

By contrast, today scientific imagery is far more prominent in the imagination, both from decades of scientific photographs from the Hubble Space Telescope and other observatories and from endless science fiction television, all propagated through the internet and extensively used on everything from merchandise to home goods. More so than in the past, science fiction forms a key part of science communication, and films are expected to be both plausible and realistic to the extent possible, in order to provide the grounded context from which the speculative aspects of science fiction can spring. Science fiction is recognised far more today than it was in the past as a recruitment tool not just for dreamers but for engineers and scientists. This was recognised by physicist Jean-Pierre Luminet in the conclusion to his analysis of the science of Interstellar:

“By inviting the spectators to wonder about deep questions on time, space, gravity and so on,Interstellar can drag the youngest to consider careers in science rather than in finance or law. It is completely up to a genre called in French «le merveilleux scientifique», that is the adventure of a science pushed to the marvel, or of a marvel envisaged scientifically.”

An equally succinct summary of the impact of physics in Interstellar and similar themes can be found in the review of the film that appeared in Physics World magazine:

“after decades in which mainstream science-fiction films have happily flouted pretty much every known physical law, a film in which the science is, for a change, mainly true, can only be a good thing. Knowing that some directors make serious efforts to get the science right is, in itself, probably enough to inspire a few viewers – and perhaps even to push them to find out why a “black” hole can glow so brightly.”

Ultimately The Black Hole and Interstellar are two very different films unified by their attempt to set human issues against some of the largest and most incomprehensible objects in the Universe. By capturing the sense of mystery inherent in black holes, and the point where the laws of physics break down, they aim to consider the breakdown of human lives, customs and assumptions. Sumptuous music and epic imagery combine to place the smallness of human affairs in context - but also to highlight that any individual human is no less complex and no less difficult to fully know than the black holes they visit. In both cases, a passage through the black hole acts as a doorway to a higher dimension of personal comprehension as well as a space-time fundamentally different to the one we know. While the choices of the filmmakers regarding how they represent that experience are open to question, both are seeking the same sense of transcendent beauty experienced by Dave Bowman in the finale of 2001: A Space Odyssey and which both adherents of religion and lovers of science experience in the pursuit of their own forms of knowledge.

The films each have their own strengths and weaknesses [7]. However both provide a window through which to look at a fascinating phenomenon in space - and the phenomenon of its appearance here on Earth.