# Trajectory

I believe in fate. Not because there have been a million things telling me that things will happen and that they have then happened – that never works – but by thinking about cause and effect, and where that leads to when you blow it up enormously.

Take snooker/pool/billiards/whatever on earth Americans call it. If you hit a ball into another one, you can work out in which direction the second ball will go, just by looking at the angles at which they collide, and a bit of geometry that is unnecessary to go into. Moreover, if you know how fast the first ball is going, then you can also figure out how fast the second ball is going to go, and if you know things like the friction on the surface of the table and the air resistance and so on and so forth, you can figure out within a millisecond (in fact, probably a far more accurate time than that) where the ball is going to end up and at what time: after 0.1 seconds it is going to be here, then after 0.4 seconds over there, then after 1.5279235862 seconds it will hit the cushion and bounce back off it, and after 2.345982525015 it will fall into the pocket. Such is the power of mathematics.

In fact, even if the second ball bounces somewhere and hits the first ball again, it can still be calculated relatively (that word was chosen deliberately) straightforwardly what everything is going to look like after a set amount of time; as well as after what amount of time any set event will occur, for example the ball falling into the pocket.

Bring a third ball into the equation. With a bit more cunning and intricacy, you still have an immaculate picture of where everything is going to be, to the same degree of accuracy as after the first story; you can predict essentially exactly where everything is at any time. Without getting into esoteric details, you can write an equation where you plug in the time at which you want to know where a ball is, and the equation spits out its exact coordinates. Magic.

It gets more difficult, but you can equally bring a fourth, a fifth, an eighth ball to the table, and you’ll be able to work out where everything will go when you send one of them moving. You can add as many balls as the table allows. Write your equations, plug in some times, and you don’t even need to throw the ball: everything that is going to happen will be encapsulated in these expressions. If you have done the maths and thrown the ball right, the formulae represent reality exactly.

If we downsize (yet at the same time taking a huge upward step), may the same logic not be applied to atoms? If we throw some atoms around, we can work out with some accuracy which other atoms they’re going to hit, and where those are subsequently going to go, so long as we know exactly how we threw the originals. Although it’s more complicated than snooker/etc. balls – there are all sorts of exotic electrical and nuclear forces involved – it is still conceivably predictable, if we work out all the forces involved.

Of course, we do not know the momentums and locations of every atom in the universe (in fact, it is literally impossible to even know this data for one atom due to Heisenberg’s uncertainty principle), but let’s put this aside for one moment and think wishfully. If we did know where every atom was going, and using nothing short of godly mathematics, would we know exactly what was going to happen to everything? Could we predict the exact future of our planet, our solar system, the pencil case sitting next to my laptop?

I see no reason why not.

There is one thing which I have so far not taken into account which does tend to ruin every kind of mathematical and physical prediction about the universe: humans. I can’t predict the future coordinates of my pencil case because someone may move it.

Or can’t I?

You (hopefully) are  made up of atoms [citation needed]. And we can predict atoms. Not just atoms, but we can predict the flow of electrons that shoot up your nervous system when a rogue atom has the indecency to bump into your skin, or a photon (particle of light) enters your eye, we can predict the ions (atoms with the wrong number of electrons) that are made to diffuse across your synapses, the electrons that these then trigger at the other end. The electrons shoot to your muscle, where they stimulates it to contract in ways we can predict, and then your muscles move in ways we can predict. It is possible (presuming we know where all the atoms in the earth are, and all the forces that operate in our corner of space – the latter of which we’re not far off from) to predict the actions of every human being on the planet. Magic.

Therefore, if one such impulse causes a muscular contraction which causes my pencil case (which is made of atoms [citation needed]) to be moved, then you can predict where those atoms of the pencil case are going to go. You can predict where the atoms of a brick are going to go when someone builds a house, or when someone hurls it through a window in protest. The human factor does not matter, it doesn’t change any of the maths: all we are is interconnected atoms anyway.

If we go back to the birth of the Earth, and somehow measure all the atoms and their trajectories that are in the universe, you can predict when the planet will cool down to let a primordial soup form, when an asteroid will hit and knock the orbit slightly, when the first molecule of DNA forms (note: no one knows how this happened exactly, but if we put all the particles in the universe into the maths, it becomes clear whether it was a lightning strike, an asteroid, or George W. Bush that started life on Earth), when those life forms are created that die, form new life, muddle around to form a more interesting shape (AKA evolution), when the human makes a fire, when s/he builds a house, when s/he makes a computer, when s/he posts a selfie. All because atoms and other particles bump in to each other, as predictable as balls on a snooker table.

This is profound. If we know the nature of all interactions, and the exact position of all particles as they were at the start of the big bang, we can predict everything.

It must be stressed, that all of this prediction (“predict” stopped seeming like a word a long time ago) would be a computationally (and just generally) ridiculous task, and impossible for any object lacking omnipotence. But that doesn’t matter. We don’t have to know where all the atoms are going to know they’re always going to go in a set direction.

Feel free to wave your hands about to try to change the path of some atoms in the air, but that’s not changing the future. The photons emitted by your screen entered your eye causing electrons to whizz about your brain like in a pinball machine, causing you to want to try to take control things, causing some muscles to contract and your arms to move about in a particular trajectory. You can’t do anything to prevent where everything is going to move because you were always going to try anyway (indeed, you’re doing it now). Trajectories of other particles have caused you to feel the way you do. You can’t change the universe, because you are a part of it. You are a part of the equation, every atom of you.

This is bleak. It seems like we have no freedom, and we are merciless to the predefined movements of particles like a balloon in the wind. We’re also all in the equation, which will define (am I just changing “predict” to “define” now?) exactly where you will go next, exactly what you do, exactly which other group of atoms you fall in love with, exactly what your children will look like, or even if your brain or your genes or the atoms around you prevent you from having children. Is everything really set in stone?

I don’t know. What (I think) I do know is that the only thing that can change the universe, the only thing that can ruin all the delicate equations and (through chaos theory) make every prediction we made completely meaningless, is something that wasn’t included in the equation in the first place.

You can call it whatever you want to, but for simplicity and visualisation points, I’ll call her Geraldine. Geraldine is not a human; she does not consist of particles (or anything else we can predict (I seem to have switched back to “predict” now)), but she can interact with them, and there is no way of predicting what she will do. Now, if Geraldine moved an atom near the start of the universe 10 feet to the left, then the equation could just add in “+10ft to the left” somewhere and the prediction would work again, although the universe would look exceptionally different to how it looked without any Geraldinian (best word ever) intervention. If, however, Geraldine dropped in every now and again to move a particle somewhere, and there was no way of predicting what the hell Geraldine was doing, then there is no equation conceivable that can predict the universe.

What does this mean? Are we free from the equation?

It does look that way. By the way, Geraldine doesn’t have to be something weird that happens, she essentially stands for a truly random event, but this is hard to come by in physics.

Radioactive decay is a candidate. When the middle of an atom is a funny shape, or has the wrong arrangement of particles, it gives off radiation and no one seems to be able to predict it as a result of some weird quantum physics. But quantum physics is incomplete: maybe radioactive decay will at some point in the future become predictable when we know where everything (i.e. literally everything) is to start with. And suddenly we’re pushed back into the equation.

The situation appears to be, that we need for there to be something random that happens in the universe to give us any escape route from being just a predefined trajectory of atoms hurtling uncontrollably but awfully predictably through the cosmos. I don’t know whether there is truly anything random; maybe some research will clear things up to discover something that is utterly undoubtably indubitably random, and we will be free from the equation.

Of course, if you believe in God, or the soul, or really anything supernatural, then you can say that this is what keeps things from being predefined. But we have discovered that they do this by altering in at random moments, doing random things. God is omnipotent because he is random.

But because I don’t really believe in God/Geraldine/the supernatural, I believe the equation exists. I know that it is impossible to discover, and that writing it down would take all the atoms of the universe as well as knowledge of all the intricacies of physics the universe has to offer.

I also don’t believe we should fear the equation. I think that if God/etc. does not exist, then it is an equally beautiful thought that it is conceivable that everything is predictable, predefined, just by measuring it all and knowing how things interact, that the universe is nothing more than an almost infinite number of trajectories that bounce around and hit each other and invent the windshield wiper and write blogs. There might be an equation that knows everything, as easily as working out where a snooker ball will end up.

Magic.