This post originally appeared on Scientific American
One of the most critically acclaimed videogames of all time had a core mechanic that bends everyday physics. Borrowed and adapted to countless tales of science fiction, the time travel in The Legend of Zelda: Ocarina of Time was fairly novel for a videogame. It allowed us to age or regress the protagonist, Link, seven years in an instant, depending on the task. This clever game mechanic didn’t have to answer to the laws of physics in a world of fairies and magic. But amid the pots and potions, can we actually make scientific sense out of the past and future Hero of Time?
A Link In The Past
27 years ago this month, Nintendo brought us a boy with a fairy and a world in dire need of saving (and small keys). In The Legend of Zelda: Ocarina of Time (OoT), we see Link battle both as a boy and a young man with the aid of the time-warping Master Sword. After slaying a one-eyed spider, a fire-breathing lizard, and an electrified jellyfish, Link returns to the Temple of Time and removes the blade. Doing so instantly transports him to the Sacred Realm, where his body and mind slumbers for seven years. Upon awakening, he returns to the kingdom, Hyrule, and finds it transformed. Unsurprisingly, that shifty-looking thief from the game’s beginning has ruined everything.In physics, time travel is possible, but only if you want to go into the future. It turns out that if you go fast enough, time dilates, or expands, for others relative to you. For example, if you were travelling in a spacecraft going 99.9999999% the speed of light, you could travel for 16 hours at this speed and find that the universe around you has aged 40 years. If you go fast enough, you can fling yourself far into the future.
Backwards time travel is another story. Unless we can develop warp drives or learn how to take advantage of wormholes and circumvent the many potential paradoxes, it looks as though the past will remain the past, and never a potential present.
But even with a scientifically accurate tweaking of time, what we see in OoT is still an oddity. It is true that if you travel fast enough, you can bound into the future. Relativity does not only affect space, however, it affects you. You actually age more slowly while traveling at relativistic speeds. So when Link yanks the Master Sword, King Arthur-style, from the pedestal we must not be seeing relativistic travel.
We can get around the perils of time travel if we take a look at what we know about OoT. When Link pulls out the Master Sword, he is spirited away to the Sacred Realm, where he is told he has been in stasis for seven years. At first this seems like a jump into the future, but Link is also told that seven years have passed in Hyrule. Link was too young (and presumably to weak) to stop the rise of evil in Hyrule, so he was sequestered until he was ready. Though nearly everything in Ocarina of Time implies it, Link does not rapidly travel forward in time, he instead lives normally through it.
This does leave one possibility for what we see in Ocarina: extra dimensions.
The Nintendo 64th Dimension
String theory in pop culture is usually shorthand for “something really complicated.” It’s true; string theory is at the forefront of resolving numerous mysteries in physics, even though it has little empirical evidence to support it. But it does make some fascinating assertions. According to the math, and in order to jive with quantum mechanics, string theory asserts that we live in a universe of many dimensions, not just four. We can do some asserting of our own and suggest that perhaps the Sacred Realm of OoT resides in one of these elusive dimensions. What better place to cloister the Triforce?
It isn’t a crazy assertion either. In the classic book Flatland, the author describes what it would be like for a strictly two-dimensional creature to experience the third dimension (you can watch Carl Sagan describe this brilliantly here). The third dimension is inhabited by 3D beings, but is completely invisible to the simple 2D creatures. They cannot even dream of what an extra dimension looks like. Similarly, if Link were plucked from above into a higher dimension, it would be as if he simply vanished from the universe and returned seven years later.
So, a young Link grasps the hilt of the legendary sword and pulls, causing him to be snatched into another dimension. He resides there until he is ready to take on the evil Ganondorf and is then plopped back into 64-bit reality. It’s not exactly scientifically accurate, but it isn’t magic either.
Extra dimensions solve the problem of how Link becomes a man, but not how he returns to his youth.
Unfortunately, we do have to resort to magic for backwards time travel. Because of the many logical paradoxes and physical impossibilities, adult Link’s transformation into child Link is fantasy. But if it were possible, one way to explain Link’s retention of his memories and items backwards through time is the theory of temporal merging, crafted to resolve logical paradoxes. Upon returning to the past, adult Link merges with his original timeline. He assumes his child body but retains everything else. It would be as if the universe is sorting itself out and preventing paradoxes.
As the recent publication of the Hyrule Historia points out, tweaks of time play a big part not just in Ocarina of Time, but also in the larger Zelda universe. In fact, there are three distinct timelines in which Link is slashing skulltulas. But unlike backwards time travel, this branching timeline isn’t just interesting, it’s theoretically possible.
Like Branches On The Deku Tree
The official establishment of three timelines in the Zelda universe was a direct result of the actions at the end of Ocarina of Time. One timeline follows what Link does after he is sent back in time to warn Princess Zelda about Ganondorf, leading to the events of Majora’s Mask, and the other follows Princess Zelda after she sends Link back, leading to the events of Wind Waker. By sending Link back in time to change the past at the end of OoT, Princess Zelda adds a whole new branch to the universe. Amazingly, we have theories that say it could really happen.
A branching universe is one of the few possible explanations for the paradoxes we get from time travel and the mysteries of quantum mechanics. Specifically, a universe with separate, branching timelines gets around a temporal paradox, where one is logically locked out of time travel. For example, the grandfather paradox occurs if you were to travel back in time and kill your grandfather. If you kill him in the past, you couldn’t exist in the future, and therefore couldn’t have travelled back in time and killed him in the first place. Parricide aside, paradoxes make the whole idea of wading against time’s current logically impossible.
To get around illogical loops, theoretical physicists came up with the “many worlds” interpretation of the universe. The theory posits that time does not have a single unfurling trunk but many braches, where each possible future rests. Such an idea can resolve mind-bending problems like the one of Schrödinger’s poor cat, both alive and dead until you observe him. The many worlds theory would state that the cat is both alive and dead, with each outcome in a separate branch of the universe, and both equally real. When we open the box to find a purring kitten, we simply happen to be in the branch where the kitten lives. The other branch has a more somber reality.
When Link is sent back to his childhood, there remains a past where he grows up and defeats Ganondorf, as he did in OoT, because that has been established in the future. However, once the returned Link warns Princess Zelda of Ganondorf’s evil, another timeline springs up. Zelda’s decision to send Link back in time splits the universe. Link is shot between temporal braches, which is way cooler than any transforming mask or incessant fairy. The only way to maintain the idea that separate Zelda games could have followed OoT is the invoking of a theory meant to resolve the loftiest ideas in quantum mechanics.
One of most revolutionary installments in gaming history is better understood with time travel and string theory and extra dimensions, themselves all having footholds in this earthly realm. If that isn’t yet another reason to praise The Legend of Zelda: Ocarina of Time, I don’t know what is.
The next time you hear a physics professor say, “Hey listen!” perhaps you should.