Time Dilation

Time dilation from Thread the Needle - first Sleep Token song, first EP, and straight away that sucker punch of time dilation comes at you right in the face. Alright then, Norn will take it and dissect it.

Albert Einstein, special relativity, physics, bitches. Basically, with this phenomenon Albert is dissing Newton, who assumed that time, or rather its measurement, is the same for all observers. He evidently never waited for the release of a new Sleep Token album, did he (although here, if we want to do this by the book, that isn’t dilation, that’s pure, unadulterated suffering)? And Einstein in his theory predicted (as was later confirmed experimentally) that this is not the case, and that the duration of a given event depends on the observer. So, sticking to references to our favourite band and simplifying the subject so much that it hurts, let’s start by setting the stage (hehe): every fan’s wet dream, the longed-for Sleep Token concert. The band come out onto the stage and even look as if they want to be there. The concert begins.

And now let’s carve this up, because the subject is complicated and the brain likes cutting corners. What isn’t dilation?

If, like me, you’re a skinny runt, then your chances of getting to the front of the stage are as good as the chances of the world’s most famous president saying something coherent. So you stand at the back, looking at the back of some great lanky bloke in front of you and wondering for the hundredth time why you actually came here, since you can barely see anything and the music is drowned out by the fans’ singing. If you’re a bit lucky, you’ll see Vessel open his mouth (for the purposes of the example let’s assume we have a clear view, the eyes of a hawk and we see exactly the moment his mouth opens). But we hear the sound of his voice only a moment later, because sound, just like a bra thrown onstage by a fangirl, needs a moment to get there. The whole class, repeat after me: this is not time dilation.

And now, we get to the juicy bit, that is: what is dilation?

Let’s start with the basic principle: light always moves at the same speed (in a vacuum, of course, which is also where all of Norn’s posts go to die), regardless of who is looking at it and how they are moving. We’ll need this to explain dilation with this deranged example instead of a normal one, from a textbook. And now let’s imagine that II has a small, glowing LED on the end of his drumstick (he can afford it) and a little mirror hung above his drum kit (ah, the whims of rock stars).

And he starts to play, and since he’s a talented drummer, he gives himself a little challenge. He raises the stick above the drum, the LED sends a flash upwards, the light travels to the mirror, is reflected and comes back to the stick. The moment the flash returns, II hits the drum.

And again.

Every return of the light reflected in the mirror is another beat from II, and the flight of the light itself very poetically keeps time.

Actually, that’s very much their style.

And then the boys do something else. The concert goes on and the stage takes off, receding from the audience at an enormous speed. And I mean seriously enormous. Not like a plane, but nearly the speed of light.

For them nothing changes. II plays on, to the rhythm of the light. Well, in reality the boys would fall off the stage, but we’re theorising here so they don’t fall (technically speaking they’d fall off during the acceleration and not from the speed itself, like on a plane: it judders during take-off and not once it’s flying, and if it’s still juddering, you can start asking whether there’s a pilot on board with us).

For them nothing changes. II plays on, to the rhythm of the light.

But what does the audience see? While the light travels upwards, the mirror and the stage move back, so by the time the light returns, II, the stick and the drum kit are already somewhere else. For the audience the flash therefore doesn’t travel straight up and down, but diagonally. And whoever has walked home from a party at night knows that a diagonal or, whatever, zigzag route is usually longer than a straight one.

Light can’t speed up (we established that it moves at a constant speed), so each of its journeys takes longer, and II has to wait for every beat. For us, the audience, II is playing more slowly. And this isn’t a delayed message like with Vessel’s voice. Even if we subtract all the delays, the answer will still be that time flows more slowly on the stage.

And if we measured the time of that flight of light, we and the members of the band, would get different results. We would measure that time flows more slowly on the stage. They wouldn’t notice any change on their end, but looking at us, they would conclude that it’s us who are running in slow motion. Both sides would be right.

Phew, I really threaded the needle with this one.