A few days ago, friend of The Aperiodical James Grime contacted me asking if I would be able to review *The Theory of Everything*. Obviously I was flattered. In a past life I did some mathematics/physics in the same ballpark as Hawking’s celebrated black-hole work so guessed James was asking because he knew I used to know something about this. Or perhaps it was because he knew that Hawking ran over my foot in a bar at the 17^{th} International General Relativity and Gravitation conference in Dublin back in 2004? Either way, James had given me a pass to go and watch the beautiful Eddie Redmayne for the evening!

The brief drive to the cinema was not Hawking-free time – no, I had time to enjoy my brief Hawking playlist put together for the occasion: Keep talking (Pink Floyd), repeated. Lots. Armed with cinema purchased consumables, your selfless reporter stepped back in time to a young Hawking’s early days at Cambridge.

As I sincerely hope you’ll go and see the film, I’ll refrain from giving away the storyline. However, like all dramatic re-enactments, the film-makers are faced with a genuine problem: how do you sustain drama when the audience knows ~~the boat sinks at the end~~ he beats the famous short prognosis of his life expectancy? With this in mind, I don’t think the following count as spoilers so here we go…

Based on Jane Hawking’s book *Travelling to infinity: My life with Stephen*, The Theory of Everything tells the story of a young Cambridge postgraduate researcher who falls in love with a fellow student, is diagnosed with a life threatening disease and coincidentally changes our understanding of the universe in which we live. The Stephen-Jane relationship is at the centre of this film and we get to see a young Stephen – who had clearly watched *A Beautiful Mind* and improved on Nash’s technique – woo the fair maiden using only the power of physics. The two leads, Eddie Redmayne and Felicity Jones, give impressive turns as they portray a young couple dealing with the difficulties of living with motor neurone disease. Some of the moments of the couple’s domestic life really highlight how much we shouldn’t take the ready availability of modern supportive/assistive technologies for granted. Also, the dalek impression is great.

Hawking’s supervisor, Sciama, features prominently throughout the film and we are treated to repeated scenes with Sciama’s future all-star group of Rees, Ellis, and Carter in addition to our hero. I confess to feeling rather sorry for Ellis in the film because, while the release of 1988’s *A Brief History of Time* is given special mention, the 1973 release of *The Large Scale Structure of Space-Time* is ignored.

Sadly, the science is lacking in this film. Other than a few tropes of scribbling equations on a chalkboard, Penrose lecturing in a weird corridor cum cul-de-sac broom cupboard and what must surely be a candidate for the world’s shortest viva, the film is sadly lacking in moments to satisfy an audience who want to see a dramatic re-enactment of the proof that black-holes radiate. Credit must be given for trying this last item using only a mug of beer! As must endeavouring to explain the difficulty of reconciling quantum mechanics with relativity using only vegetables.

Hawking’s work on singularity theorems lurks in the background for the first half of the film while his famous black hole result occupies this space in the latter half when the writers felt they should again allude to his scientific career. For readers unfamiliar with the singularity theorems of general relativity (shame on you) here’s a potted version: the mathematical framework for this result is differential geometry. More specifically we assume that space and time come together in a manifold structure with a certain way of measuring separation of points using a rank two tensor called a metric $g_{ab}$.

A key object here is the Einstein equation

\[R_{ab} – \frac{1}{2} R g_{ab} = 8\pi T_{ab}\]

where $R_{ab}$ and $R$ are curvature terms known as the *Ricci tensor* and *Ricci scalar* respectively and $T_{ab}$ is the stress energy tensor of the matter component of your spacetime universe. For unit buffs, we’re working in *natural units* where Newton’s constant and the speed of light are set to one. Roughly speaking, Einstein’s equation says “curvature = matter” (i.e. matter bends spacetime, or spacetime bends telling matter how to move).

This metric encodes all the information about the curvature of spacetime and frees up limitless pots of cash for demonstrators to spend on rubber sheets and bowling balls.

A stripped down version of the result Hawking and Penrose proved in 1970 shows that if your spacetime satisfies the Einstein equation and the strong energy condition (a condition which requires the matter in your universe to behave nicely) then your spacetime must contain an incomplete lightlike or causal geodesic curve. Roughly speaking this means that there is a path in spacetime which you can follow which stops abruptly due to it meeting a missing or edge point of the manifold (the spacetime singularity). These singularities have enormous significance: the singularity in the Schwarzschild solution is a key feature of this black hole, and that of the Friedmann-Robertson-Walker solution of a homogeneous and isotropic universe is the “big bang”. For readers seeking a more precise statement of this singularity theorem, and its proof, in the full and glorious language of general relativity then please do check out Hawking and Ellis’ book. However, for a free overview you can read Sean Carroll’s lecture notes (PDF).

However, if the film runs the risk of not sating the alpha-nerd in you then be of good cheer for there is definitely something to celebrate: Redmayne’s portrayal of the developing motor neurone disease is utterly compelling as he successfully transforms himself from gawky postgrad to the Hawking we now recognise.

We’re really being spoiled this year with the Turing and Hawking biopics, not to mention that the filming of Ramanujan’s has already started, so get out there and support your local multiplex.

The scene in which Hawking runs over my foot didn’t make the final reel. I’m hoping for a deleted scene on the DVD.