While I was on holiday I decided to watch Interstellar. This was a terrible, terrible mistake, but at least you’re getting what is hopefully a reasonably entertaining blog post out of it. Needless to say, though, this post is going to spoil the hell out of the film, so don’t read if you haven’t seen it yet.
Interstellar is the worst science fiction film I’ve seen since Prometheus.
To understand my particular problems with Interstellar you have to know about the difference between hard science fiction and soft science fiction. Soft science fiction is mainly concerned with telling a story, and using “science” to enable that story. It doesn’t particularly care how its science works — hence the quotation marks — and if it knows what’s good for it it won’t even bother with an explanation unless it’s directly relevant to the plot, instead presenting objects and concepts that outright break the known laws of physics as a fait accompli. This is an approach that works, and works well; it’s the story that matters to soft science fiction, and nobody is going to care about the precise physics behind lightsabers or artificial gravity unless you make the very poor decision to point it out to your audience. Soft science fiction requires lots of imagination and very little actual scientific nous to write, and so it’s not particularly surprising that soft sci-fi encompasses the vast, vast majority of science fiction. Pretty much every single sci-fi film, television show, and 95% of sci-fi books released in the last fifty years are soft science fiction.
I say this because I want to make it clear I’m not about to brutally suplex Interstellar through a table just because I like nitpicking. I’m very capable of enjoying sci-fi stories that screw established science up into a little ball and throw it into the dustbin, because if they’re written well enough and don’t go out of their way to draw attention to it I can suspend my disbelief and just accept it as something that’s necessary to the story. Prometheus was soft sci-fi, and my issues with that largely stemmed from the fact that it involved the most imbecilic group of movie scientists I’ve ever seen rather than any of its actual “science”. Soft science fiction is fine, in principle. If Interstellar was soft sci-fi it would still have problems, but those problems would be that it is terribly written and nonsensically plotted, not anything to do with its science (or lack of it).
Unfortunately Interstellar is not soft sci-fi. Or at least, on the outside it doesn’t look like soft sci-fi. Instead, Interstellar is masquerading as hard sci-fi. Hard sci-fi differs from soft sci-fi because the science in hard sci-fi does matter. It might take a few liberties, or rely on one or two big assumptions about future science (the possibility of FTL travel is the usual culprit), but otherwise hard science fiction is written to be as faithful to current real-life scientific knowledge as possible. It’s effectively the reverse of soft sci-fi in that the stories it tells are now all about the how of the science that soft sci-fi just ignores; most hard sci-fi tries to come up with plausible solutions to near future problems such as the colonisation of another planet, and the draw of the story is either the science itself, or how human beings would react when confronted with the stark reality of certain modern scientific concepts. Because it’s actively relying on the science as the central support of its story hard sci-fi is consequently much harder to write well than the soft stuff, which is why you don’t often see hard sci-fi in the cinema. Not only do you have to be really up on your science, but if you’re faced with a choice between “something cool happening on screen” and “obeying the laws of physics” you usually have to choose option B, which doesn’t exactly make for a high-grossing summer blockbuster.
Except now we have Interstellar, a seemingly hard science-fiction movie that made all of the money at the box office last year. It did this despite repeatedly invoking real-world scientific concepts such as gravity and relativity, and despite going out of its way to present itself as a “realistic” vision of space travel right down to the not-having-any-sound-effects-during-space-sequences trope. It also did this despite straight up not being a very good movie, but that doesn’t stop the Transformers franchise and so is probably outside the bounds of this discussion.
The first half hour of Interstellar is probably the most interesting. It’s set on a decaying, technologically regressive Earth afflicted by a blight that’s slowly killing off the world’s staple food crops and turning the topsoil to dust. The main character, Cooper, is a washed-out astronaut who is now scratching a living as a farmer, and whose frustration with his world’s backwards, insular outlook on life drives him to seek some form of escape from it. The world-building that goes on here is perfectly respectable, and it felt like the beginning to a half-decent John Christopher novel. But then Cooper gets his wish, and the movie goes completely off the fucking rails.
Cooper is made the leader of a party of astronauts that is sent through a wormhole that appeared 50 years ago to see if they can find any planets suitable for colonisation. A wormhole? Fine, whatever, you’ve got to get the astronauts to another system somehow and so I’ll swallow that – the existence of wormholes isn’t exactly forbidden by the laws of physics, although the existence of a stable wormhole that you can traverse from one side to the other requires some extreme fudging of energy densities1. On the other side of the wormhole they find three planets orbiting a black hole called Gargantua, which is stated to have 100 million times the mass of our Sun. This makes it a mid-range black hole – we know of supermassive black holes with masses exceeding tens of billions of Suns, while the lower limit is like four Suns or something — but it’s still not exactly the sort of place I’d want to start humanity anew for the following reasons:
- Black holes aren’t very big on the whole providing heat and light for the purposes of sustaining life thing. Interstellar fudges this too by saying that the black hole’s accretion disk is providing a curiously sun-like environment for the orbiting planets, but while it’s true that accretion disks do give off a lot of radiation it’s usually in the form of X-rays and other nasty stuff that would make any planets present decidedly unhealthy places to live.
- Black holes are tidal giants. This is a point that Interstellar chooses to entirely ignore, but black holes will destroy planets long before they go anywhere near the event horizon thanks to tidal stresses. Even big planets do this – Saturn’s rings are basically chunks of moons and planetoids that wandered inside Saturn’s Roche limit, and if a pissant little gas giant can do that imagine the Roche limit a black hole with 100 million times the mass of the Sun will have. In order to survive a planet would have to be a very, very, very long way away from the black hole, which then poses some additional problems for getting adequate amounts of heat and light to sustain life.
- It’s a sodding black hole. I’m seriously struggling to think of a dumber idea than settling a new colony within spitting distance of one. Even digging out a planetoid in deep space and living underground would be more sensible.
But our intrepid heroes aren’t letting this stop them. Despite Michael Caine and Cooper’s daughter blathering on and on about how getting a look inside a black hole will let them “solve the problem of gravity”, the black hole in Interstellar has a curious lack of it and functions almost identically to Earth’s Sun for almost the entire length of the movie. It’s pretty much there for two reasons.
- To provide the usual deus ex machina that movie black holes do at the end of the film.
- To allow the writers to make a spectacular hash of the concept of gravitational time dilation.
They waste no time with the second one, as the first thing the astronauts do is make the mind-numbingly stupid decision to land on a planet so deep inside the black hole’s gravity well that seven years will pass in “normal” space for every hour they spend on the surface. I have a number of problems with this sequence.
- You would have to be bloody close to the event horizon of even a 100 million Sun-mass black hole before you experienced that degree of time dilation. Gravitational time dilation is much like relative velocity time dilation, where you don’t experience significant time dilation effects until you’re all the way up to .99c; otherwise it’s something that’s not really noticable on the human scale. As we’ve just established, being that close to the event horizon means your planet just gets pulled apart and there’d be nowhere to land on. For that matter the spaceship would get pulled apart and there’d be no astronauts to land on it.
- There’s a hefty amount of technobabble about how to land on this planet in such a way that it will save fuel. I have bad news for the astronauts: if your planet is sitting at the bottom of a gravity well so deep that you only age one hour for every seven years that pass outside of it, then there’s no amount of fuel that’s going to get you back off the planet’s surface again. We have enough trouble getting out of Earth’s gravity well, for crying out loud.
- One of the reasons they land on this planet is because there’s an all-clear signal being sent from a pathfinder ship that was sent ahead of them several years ago. When they get there they discover that the pathfinder ship is wrecked, but thanks to the time dilation in the planet’s frame of reference the ship has only just crashed. This is a nice idea, with one extremely significant flaw: if the gravity well was that deep then any transmissions from the pathfinder spacecraft would be incredibly redshifted, and it would have been extremely obvious to the astronauts that something was up. Assuming that they weren’t yet another collection of dumb movie scientists, that is.
- I don’t even know what was going on with the ankle deep water and the huge tidal waves that are somehow not spotted by the astronauts on their initial approach. Have they never heard of side-looking radar? And yes, if you’re that close to the black hole you’re going to experience significant tidal effects, as I’ve mentioned several times, but I somehow don’t think that this is what was on the filmmaker’s minds when they shot that scene. Anyway, I’d be more interested in how the planet has managed to retain a liquid ocean without having it all escape into space under the gravitational influence of the black hole. Ditto any atmospheres and, well, solid matter.
There is a lot of stupid concentrated on that first planet, but Interstellar still has a couple more stops to make on its tour of idiocy. First there’s Crazy Matt Damon’s planet, where the ice surface they spend their time tromping around on is apparently a collection of floating solid clouds. Which is ludicrous. Perhaps in response to the frank impossibility of his environment, Crazy Matt Damon goes crazy and attempts to kill the astronauts and steal their spaceship; the ensuing fracas kills the remaining redshirt astronaut and damages the spaceship so badly that Cooper is forced to attempt some sort of slingshot maneuver around the black hole to get Anne Hathaway to the last remaining candidate planet. He does this by burning all of the fuel they have left and then jettisoning the spent shuttle vehicle he’s piloting into the black hole to reduce the spacecraft’s mass. This is not the dumbest thing that happens in the film by a long way; we’ve already established that they must have some sort of magical future fuel/engines that can get them out of any gravity well and so slingshotting around the black hole while dumping unnecessary ballast is actually quite a good idea. Sadly there’s then an extended sequence where Cooper falls into the black hole, which is inevitably very, very stupid indeed.
- First, there was some gobbledygook earlier in the film where Gargantua is described as a “gentle” black hole, where somebody might be able to dip inside the event horizon and escape again with the data required to solve Michael Caine’s gravity equation. This is nonsense. The whole point of the event horizon is that it’s the point of no return: once you cross it, not even light can get back out again. That’s why it’s called the event horizon; we can’t see anything over it. That’s why black holes are black. Once you’re over that horizon, falling towards the central singularity is inevitable.
- This is also the part where Interstellar contradicts its own twisted movie logic as well as the laws of physics. The accretion disk around the black hole is burning with a heat comparable to the surface of the sun. It must be in order to provide the Earth-like light source that illuminates each of the worlds the astronauts have visited, and I think there’s a part where this is outright stated to be fact by somebody or other. Cooper somehow falls through this incredibly hot accretion disk without being burnt to a cinder and reaches the black hole’s event horizon. Maybe they’ve discovered super-asbestos in the future and lined their spacesuits with them or something.
- Oddly, Cooper would probably survive the tidal forces present at Gargantua’s event horizon. This is because the radius of the event horizon increases more or less linearly with the mass of the black hole, while the strength of the tidal forces obey an inverse square law that means they get exponentially weaker the further out you go. A small black hole on the order of a few solar masses will have a tiny event horizon, but it’ll kill you long before you reach it. A supermassive black hole like Gargantua, on the other hand, will have an event horizon that extends some way beyond the black hole’s lethal radius2. Cooper’s death is inevitable once he’s crossed it, but he’d at least live long enough to see what was inside it.
Of course the interior of the black hole turns out to be some pseudo-mystical time travelling bollocks that ties up the story, as I’d been expecting almost from the very beginning of the film. In fact I’d seen every single plot twist bar Michael Caine’s deathbed confession coming the moment the character or concept was introduced because Interstellar is, as I have already stated, a terribly written movie that hews to all of the worst soft sci-fi tropes despite having dressed itself in hard sci-fi clothing. And this is my problem with Interstellar: it’s actually a soft sci-fi movie, but it’s explicitly linked to the present day and repeatedly invokes real-world scientific concepts in the manner of a hard sci-fi movie, right before mangling them horribly because they just get in the way of the story it wants to tell. Unfortunately if you invoke that real-world science as heavily as Interstellar does you have to be partially bound by it, otherwise there’s no point; you might as well have made a more fantastical film with lasers and aliens.
Yet despite mentioning it repeatedly Interstellar doesn’t use its science in any interesting fashion bar its brief (yet incorrect) flirtation with time dilation, and it’s a much weaker film as a result of cloaking itself in a hard sci-fi raiment that, after the most cursory of inspections, turns out to be the emperor’s new clothes. It would have been far better if it hadn’t made a point of making a point out of the science; if it didn’t go out of its way to draw my attention to how wrong it was at every single turn. It wouldn’t have been a good film, but I probably would have been able to suspend my disbelief the whole way through rather than having it repeatedly snap under the weight of the film’s scientific bullshit. As it is not only is the science awful but Interstellar has a worse grasp on its internal logic than the Fast and Furious series does. At least those movies are fun. Interstellar, on the other hand, is a dull, dreary and pointless expedition into the absurd, and I deeply regret having watched it at all.
(I did like the robots, though.)
- One thing that did amuse me about this was that the pencil-through-folded-paper exposition one of the other astronauts does for Cooper (about five minutes before they fly into the thing – you’d think Cooper would have boned up on his wormhole physics a little earlier than this) is exactly the same as the wormhole explanation in Event Horizon. ↩
- Of course this does mean that that water planet should have been orbiting inside the black hole’s event horizon in order to experience that amount of time dilation. ↩