This article is about the ending of Interstellar (and has a couple tidbits from True Detective). If you haven’t seen the film or don’t want to have the ending spoiled for you, stop reading right here. Alright? Alright, alright.
Someone once told me, ‘Time is a flat circle.’ Everything we’ve ever done or will do, we’re gonna do over and over and over again.
When detective Rust Cohle delivers those lines, it’s a compelling monologue that makes you believe he is either brilliant or insane, maybe both. The detectives opposite Rust shoot each other glances that say, “This guy sounds crazy.” But that doesn’t mean Rust is wrong. There’s a lot of science to suggest the opposite – time might have flat circles, and it explains the ending of Interstellar.
Everything We’ve Ever Done or Will Do
In Christopher Nolan’s latest epic, Matthew Mcconaughey and crew are tasked with finding a new Earth. There isn’t any planet within our solar system that can sustain human life, so humanity must look elsewhere – to another galaxy. To get there by normal means would take hundreds of thousands of years, but there’s a shortcut orbiting Saturn. Someone has put the end of a wormhole there, and we’ve already sent people through it.
Through the wormhole, Mcconaughey, aka Cooper, finds lies, time dilation, and disaster, which all lead up to a desperate Hail Mary pass – a fall into a black hole known as Gargantua to gather the data humanity needs to solve the gravitational equations that constrain us to Earth. But instead of getting spaghettified upon entry, when Cooper enters the black hole he finds himself in a 5th-dimensional realm, able to send messages to his daughter in the past. These messages let Cooper’s daughter solve the gravity equations and uplift humanity from the dying Earth. Cooper is eventually released from the black hole and recaptured somewhere near Saturn. Humanity has been saved.
But how could Cooper save the world if him doing so is dependent on him already succeeding in the future? Well, time is a flat circle, so to speak.
Closed Timelike Curves
Let’s get the caveats out of the way. First, almost all the weird physics that you saw in Interstellar are based on theory and math alone. We have no physical evidence that wormholes actually exist or that anything can/could travel through them. We’ve never actually seen a black hole, and you would almost certainly die while falling into one. In short, a lot of the science in Interstellar is likely either pure speculation, impossible, or fatal.
We do have math behind us, however. Theoretically, if you could create and manipulate wormholes, for example, you could make a time machine.
But more importantly for the ending of Interstellar, certain solutions to Einstein’s equations of general relativity allow for what are called “closed timelike curves” – closed loops of time and space itself. Entering a closed timelike curve tomorrow means you could end up at today.
And where does the math say closed timelike curves may exist? Near the ring-like singularity of a black hole spinning at near light-speed. These are called Kerr black holes — Roy Kerr discovered this solution to Einstein’s equations in 1963 – and are presumably what the black hole of Interstellar is, at least according to Kip Thorne, the physicist whose theories informed the entire movie. So, if Cooper could enter Gargantua, enter a closed timelike curve to an arbitrary place in space and time (yes, even that five-dimensional space is theoretically plausible, if not the messaging that Cooper does with his daughter…) he might be able to simultaneously be in the future saving humanity and existing in the past to follow his own instructions (the coordinates of the NASA facility).
(These topics are incredibly dense and complicated, and I am making some grand assumptions here. For more reading on the science in Interstellar, check out this post from an actual physicist.)
That’s more than enough trippy physics to mentally trip over, but there is still another unresolved issue: Who put the wormhole near Saturn so that this whole adventure could kick-off in the first place? Cooper claims that future humans did.
This is where things get really weird, and where Rust Cohle comes in.
A Flat Circle
You’ve probably heard of Einstein’s theory of relativity before but it’s hard to take it truly to heart. If you really follow the theory, the separation between past, present, and future breaks down.
For example, because of general relativity, what we think of as “now” depends on where you are in the universe and how you are moving. If “now” for you is you reading this sentence, an observer moving in some other part of the universe could interpret your now as already have happened or not yet happened. In other words, there are many ways to slice the continuum of space-time, all depending on how time is moving for the observer.
Given how much “now” can vary across our universe, the conclusion is that the past and future as we know them must be real, as they could be somebody’s now based on relativity. If the past, present and future are real, and not just remembered or imagined, then a closed timelike curve that traversed past and future could be its own, self-contained, self-causing loop of events within the space-time continuum.
Here’s my m-brained theory: At some point in the space-time continuum, humans are advanced enough to manipulate space in such a way that we can curve space and create wormholes. But this advanced civilization is only possible if Cooper finds the information within Gargantua needed to solve our equations (also probably impossible) and transmits it to his daughter. This can only happen, however, if humanity survives to be advanced enough to to send a wormhole into the past. It’s a loop.
These events can’t happen without each other, which doesn’t fit into our traditionally linear view of time. Because it was possible for Cooper to enter a closed timelike curve – Murphy’s Law, right? — the events that make it possible for him to do so must also exist in the future. View all this mess from above, from a higher-dimension, and you’d see time as a flat circle. You’d see Cooper always going through that wormhole because he always has.
Based on the theories Interstellar was hinting at, no matter how realistic or supported they may be, that would be my best guess. I’ve read papers and talked to scientists, but it’s hard to nail down exactly what Nolan was going for here. Maybe that’s what he wanted, or maybe he was just using bad science to confuse us.
The Secret Fate of All Mcconaugheys
Rust Cohle embraces some kind of cosmicism – the famous philosophy of H.P. Lovecraft – stating “humans are particularly insignificant in the larger scheme of intergalactic existence, and perhaps are just a small species projecting their own mental idolatries onto the vast cosmos, ever susceptible to being wiped from existence at any moment.”
In a way, this perfectly captures where the tension is for Cooper in Interstellar. There is no god to save us, and the universe is cold and uncaring. We have to save ourselves. And if the whole of the film is some kind of time loop, then Cohle’s philosophy on life and “flat circle” theories ring even more true.
But let’s go deeper. Mcconaughey was in Interstellar and Contact, both of which used wormholes for travel, and both of which used the theories of physicist Kip Thorne (Carl Sagan asked Thorne for advice when writing the book on how to make some scientific sense out of it). In True Detective, Mcconaughey apparently describes the ending to Interstellar. Are all Mcconaugheys linked by wormholes between parallel universes that cause each other because they cause themselves? I don’t know…probably!
Have your own Interstellar theory? Let me know in the comments below. Alright, alright, alright.
Kyle Hill is the Science Editor of Nerdist Industries. Follow on Twitter @Sci_Phile.