Star Wars' Newtonian Universe

With all the interplanetary zipping around in the Star Wars universe, and all the talk of hyperspace, you might imagine that everyone – Jedi and Sith alike – would spend their evenings and weekends brushing up on Einstein and relativity. Well, not our Einstein of course; after all, this isn’t our galaxy, it’s a galaxy that’s “far, far away.” They’d need their own frizzy-haired genius, of whatever species. But a closer look at the Star Wars movies reveals a remarkably un-Einsteinian universe. In fact, it seems to owe more to Newton than to Einstein.

Let me explain.

From the moment Luke and Obi Wan stroll into the Mos Eisley cantina on Tatooine, it’s clear that the Star Wars galaxy – wherever it is – is a place of extraordinary diversity, populated by extraordinary creatures inhabiting extraordinary worlds. Tatooine is all desert; Dagobah is covered in dense jungle; Hoth is blanketed with snow. And that’s before we encounter Yavin, Endor, Naboo, Jakku, Ahch-To, and the rest. These worlds are sprinkled throughout the galaxy. They extend over space – but they share a single time. This is reflected in the opening “crawls” that precede each film. Recall the first sentence of the Episode IV (A New Hope) crawl: “It is a period of civil war.” Where is the civil war happening? Presumably, throughout the galaxy. And when is it happening? Why, “now” of course. Everywhere, all at once. Or consider the first of the prequels, The Phantom Menace (sorry). Its crawl begins, “Turmoil has engulfed the Galactic Republic. The taxation of trade routes to outlying star systems is in dispute.” When is the dispute happening? Again, the answer is “now.”

In the Star Wars universe, there’s just one now, one timeline. Of course, the various worlds have pasts and futures: Alderaan has a past, in which it’s a well-populated, peaceful world; and it has a future, as a zillion little bits of space dust. Relativity doesn’t take away the concepts of “past” and “future”; real planets in real galaxies have pasts and futures, too. But, unfortunately, relativity wreaks havoc with the concept of “now.”

It wasn’t so in Newton’s universe. In his masterwork, the Principia, Newton famously declared that “absolute, true, and mathematical time, in and of itself and of its own nature, without reference to anything external, flows uniformly.” Since nothing could affect the passage of time, it had to be the same for everyone, everywhere. It’s as though there was a great “master clock” for the universe, playing a similar role to that of a town clock in the centre of a medieval city. One clock, one shared time.

In Einstein’s universe, this becomes untenable. Of course, relativity did a lot more than just muddle up the concept of “now.” In the first part of Einstein’s theory, known as special relativity, Einstein showed how measurements of space and time depend on the relative motion of the observer and the thing being observed. That means, for example, that if two identical spaceships pass each other at high speed, each will observer the other as having a shorter length, and each will observe a clock on board the other ship as running slow (physicists call the latter effect “time dilation”). As well, as a spacecraft approaches the speed of light, it gets heavier; it will become more and more difficult to make it move faster, and in fact it will never actually reach the speed of light. The second part of Einstein’s theory, known as general relativity, adds some new complications by bringing gravity into the picture: A clock at the bottom of a valley will tick more slowly than an identical clock on the top of a mountain. Things get even wonkier near black holes. Those are all pretty heady ideas, and wildly counterintuitive. This is the “relativity of now,” or, in physics jargon, the “relativity of simultaneity.” This is how I put it in my 2008 book, In Search of Time:

What do we mean when we say a particular event is happening “now”? When we use the word “now,” we are really comparing two events: I can snap my fingers and then ask whether some other event was simultaneous with my finger-snapping or not. If it is, I say that the event is happening “now.” In the Newtonian universe, I can legitimately ask, “What events in the universe are happening right now?” The answer would be a unique set of occurrences, scattered throughout space but lying on a single “slice through time.” I can snap my fingers at, say, noon Eastern Standard Time on December 1, 2008, and every event, everywhere in the universe, is either simultaneous with my finger-snapping, or not. That was fine for Newton, but not for Einstein… In special relativity there is no universal agreement among observers as to whether two events actually are simultaneous or not – and thus there can be no universal “now.” As Einstein remarked, “There is no audible tick-tock everywhere in the world that can be considered time.”

As with relativity’s other effects, these disagreements over what-happened-when are too small to notice in everyday, terrestrial affairs. No matter how many jet flights we take, no matter how many times we zip from continent to continent, the disagreement between our clocks will be no more than a few milliseconds (a discrepancy that scientists have measured using atomic clocks). For all practical purposes, it really is as though our lives are governed by an invisible master clock. 

But try zipping across interstellar distances, and all of that goes out the window. Keeping the affairs of a galactic civilization in synch would be a hopeless task. (This means that maintaining Star Trek's Federation would be as much of a non-starter as trying to run Star Wars’ Empire (or Republic, or Senate, or council of Jedi knights). 

Now, both Star Wars and Star Trek imagine something like faster-than-light travel – a necessity for getting from one star system to another in a reasonable amount of time, right? Unfortunately, such speedy travel does nothing to get around the problem of time dilation (something that the makers of the 2014 movie Interstellar got right). A lot of problems crop up when we try to make sense of light-speed (or faster than light speed) travel, but, putting those aside, this effortless galactic leaping about shows just how committed Star Wars is to the Newtonian “now.”

Consider one of the key plot-points of The Last Jedi: On more than one occasion, Rey and Kylo are able to communicate across interstellar distances, using a kind of telepathy (humorously described by some fans as “ForceTime”). (It’s not a completely new phenomenon within the franchise; Luke and Leah displayed telepathic abilities as early as The Empire Strikes Back, and Obi Wan seems to be “instantly aware” of the destruction of Alderaan in A New Hope.) Let’s say telepathy was an actual thing. What would it be like to use it to communicate with someone on the other side of the world? Well, except for the mind-reading part, it would be a lot like placing a Skype call; a few clicks and you’d instantly be able to see and hear what someone was doing on the other side of the globe. But once the distances increase from a few thousand miles to a few billion miles, we run into trouble. It’s not just that the telepathy signals would have to travel faster than the speed of light – after all, if we can suspend our disbelief for ships travelling through hyperspace, it’s not so hard to imagine telepathy working by means of a similar trick. We can imagine that Rey sees what Kylo is doing “now” (e.g., forgetting to put his shirt on), and vice-versa. The problem is, if the two characters are moving relative to one another – and presumably they are – their conversation will quickly get out of synch. Even worse, later bits of the conversation could end up taking place before earlier bits – a version of the famous “grandfather paradox.”

The easiest way to enjoy the Star Wars films, of course, is to just not worry about any of this. (I get it: they’re not documentaries. And if you didn’t worry about ET’s flying bicycle, you’re half way to accepting the Force.) The harder and rather more masochistic way to get through the films is to keep a tally of which scenes violate which laws of physics, and imagine how those laws would have to be tweaked in order for the galaxy-spanning events of Star Wars to make sense. But there’s a comfortable middle ground, which I rather like: Take everything that happens in Star Wars at face value – but instead of picturing the action as happening in a galaxy far, far away, imagine the various events happening over the surface of a single planet (maybe Earth-sized, maybe Jupiter sized – but not too much bigger). We just need to imagine a world in which some areas are covered by desert, some by snow, and so on – which in fact is a pretty good description of Earth. On such a word, clocks don’t get significantly out of synch. Telepathy (if it existed) would be a convenient alternative to Skype. A civil war – or a dispute over taxation – could be a topical news item for all inhabitants, all at once.

George Lucas was a genius of enormous imagination. But I sometimes think of his universe as a small, planet-sized affair, with a single clock keeping track of events. It’s a wondrous – but Newtonian – world.