Saturday, 6 October 2012

It's hardly quantum physics!

Now, I ain’t gonna lie to you: I’m no expert when it comes to Quantum Physics (haha, no shit!) BUT, what I am gonna do is explain to you what all the hoo-ha was about a few months ago because, if you’re like most people (and me, until not so long since) you’re probably wondering, 

“What the chuff is a Higgs Boson?”

I’ll help you with that. I’m not going to give you lengthy scientific explanations (as if I could!), but I’ll give you the bare bones of it. So, quit hovering over the mouse pad; this is gonna be REALLY simple and basic. You will not walk away from this a physics genius (unless you already are, of course) but you WILL have a rough understanding of what quantum physics is about and you’ll maybe even become a little bit interested in the subject – imagine that!

“What is quantum physics?”

All scientists are trying to do is to understand what’s going on. Through experiments, they’re trying to work out a set of rules to explain how and why things do what they do – they want to give everything a formula. You know, like the laws of gravity – there’s a formula to explain what’ll happen if you drop a piano out of a second story window. With these rules they’re ultimately striving to explain the big picture - why we’re here, where we’re from, where we’re going but, you know, we’re kind of a long way off that yet.... But, the questions we ask when we stare at the stars at night? The stuff that religions and spirituality sometimes offer explanations for? There are scientists trying to figure this stuff out – cool job, huh?
And Classical physics (or Newtonian physics, named after Sir Isaac Newton) has rules to explain how everything works for things above the size of an atom – ace! Then someone came along and split the atom and realised that the tiny stuff making up atoms doesn’t adhere to the same rules – bugger; back to the drawing board!

So, what physicists have been trying to work out for about a hundred years is the rulebook for the tiny stuff that makes up atoms and that’s what quantum physics is concerned with – finding the formula to explain the behaviours for the tiny stuff. And although there are theories, it’s only on 4th July this year that scientists at CERN think they may have decided which one is correct.

"What’s CERN?"

CERN is a nuclear research centre in Switzerland from where the World Wide Web (t’internet!) was created. It’s also home to the Large Hadron Collider which is a gigantic piece of equipment built underground and shaped like a tyre about 17 miles in circumference. Scientists conduct experiments by firing particles through the LHC to hit each other and use the results of these experiments to work out which of the current scientific theories may be correct.

"What scientific theories?"

So, there are two types of physics:

Classical or Newtonian physics (named after Sir Isaac Newton) which is the stuff you were taught at school and includes things like the rules about gravity, and cause and effect, and is all very neat and tidy, and applies to everything above the size of an atom. 

Then there's Quantum mechanics which has theories about all the tiny stuff at atomic level and below that do not follow the same rules AT ALL as the bigger stuff. Basically, there is maths to prove that the little stuff (particles and waves) cannot be pinned down in terms of location, and measured in terms of speed because, as soon as you observe them, they respond to your observation so there's no way of measuring what they're doing when you're not looking! (A bit like the toys in Toy Story or naughty children – when you watch them they behave differently to how they behave when you’re not looking...)

So the really tiny stuff has its own set of rules different to the rules used by the bigger stuff, and scientists had to work them out and came up several theories, the favourite being one called the “Standard Model”. The Standard Model says that the whole universe is made up of 12 different types of particles, and four different forces. It’s currently believed that these 12 types of particles that make up everything in existence cannot be split into anything smaller. However, the problem is that according to the Standard Model, matter inherently has no mass, and the Standard Model does not explain where mass comes from. 

"What’s mass?"

Mass is the thing that stops stuff moving at the speed of light (about 300 million miles an hour). If you had no mass you’d move at 300 million miles an hour, you’d have to, those are the rules. But, seeing as you are able to move more slowly and, indeed, stand still, you obviously have mass. And this is where Peter Higgs and his science crew stepped in and said there must be a “field” – they call it the Higgs Field (after Peter) – that particles pass through or bounce off in order to slow them down. 

What they said is if the Higgs Field DOES exist then, after the passing through/bouncing off process, there’ll be a particle left over, which they named the Higgs Boson (Higgs after Peter, Boson is just the name for a particular type of particle) - and that is what was found by scientists working at CERN in July; a particle that behaves in the way they expect the Higgs Boson to behave. Which means that the Higgs Field probably exists.

Now, it’s early days; they’re still not 100% certain that this particle IS the Higgs Boson but, if after more experiments, it is found to be, that would make the Standard Model theory correct and would mean that science has found the scientific formula to explain how the little stuff works – hurray!

“If the Higgs Boson is the “God Particle” does this mean they’ve found God?!”

No, it means nothing of the sort. The God Particle is a label made up to sell newspapers – just ignore it.

“This is all too abstract. What does it mean in the real world?”

Excellent question. Remember I said that the small stuff doesn’t behave like the big stuff? Well, the main difference is that the small stuff behaves differently when it is being observed. What this means is that waves (of energy) only turn into particles (of matter; stuff you can touch) when they are being observed. Otherwise they remain as energy, waiting to be turned into something. WHAT?! OK…

In any situation, there is the potential for several things to happen – these potential happenings are called “superpositions”. These superpositions exist in the form of waves, i.e. they haven’t turned into particles of matter and so they don’t yet exist in our reality. When an observer witnesses the outcome, only then does the wave turn into a particle and come into existence, i.e. become what we see as reality. Yes, I know this is a very peculiar concept to understand but, like I said, the small stuff doesn’t behave like the big stuff AT ALL. To make it easier to grasp there’s a famous thought experiment that could help you get your head around it, called, “Schrodinger’s Cat” – I’ll also simplify it so make it more straightforward.

In this thought experiment (you don't have to worry about the cat, it didn’t really happen, it’s just something to help you understand the concept), a cat is placed inside a sealed metal box along with a thin glass tube of poisonous gas. If the tube of gas were to break, the cat would be instantly poisoned and die. There are two superpositions (possible situations) here:

1) the glass tube of poison is still intact and the cat is still alive (yay!)

2) the glass tube of poison is broken and the cat is dead (booo!)

While the box is sealed and the cat is not visible, both situations, or “superpositions” potentially exist in wave form. It’s only when the box is opened and an observer can witness the cat that one of the superpositions becomes reality – that the waves of energy become particles of matter and the glass tube is either broken and the cat is dead, or the glass tube is still intact and the cat is alive.

However, there are two schools of thought with quantum physics. One is that ALL possibilities come into existence, i.e. if you open the box to see the cat is dead, at the same time another you in another parallel world opens the box to see the cat is alive. This school of thought that there are infinite universes with infinite situations going on is called the Many Worlds Interpretation. The other theory is that all other possibilities disappear (or wave function collapse) and you’re left only with the one you’re witnessing (i.e. the cat being either alive or dead) – this is called the Copenhagen Interpretation. Just for info. ;o)

We don’t yet know whether there are infinite parallel universes (Many Worlds Interpretation) or whether there’s just the one (Copenhagen Interpretation) – what do you reckon? Is there an infinite number of you wandering around doing infinite stuff somewhere out there? Would this explain the feeling you sometimes get of déjà vu, or the stories you see in dreams..?

“Is there a Theory of Everything?”

If it’s the case that our observations affect what happens at the sub atomic (tiny) level, and that everything at the sub atomic level is what makes up everything in our “big” (human) world, could it be that our observations/thoughts/intentions, affect what goes on in our human world? There are a lot of people will tell you that it definitely does. But although there are scientists working on trying to find a set of rules that includes everything from the huge to the tiny (with incomplete theories such as string theory, superstring theory and M-theory) as yet, none have been proven accurate with experiments… If in the near future one of these theories of everything become complete then perhaps we can talk again.

In the meantime, I hope this has helped you to get a basic grasp of what quantum physics is about. 

(Science boffins out there, if there’s anything here you know is not accurate, please do let me know so that I can edit it – like I say, I’m no expert and I’ll very much appreciate your help!)

1 comment:

  1. Nicely written Lisa, I'm a total dunce when it comes to this stuff but it's all very interesting so thanks for taking the time to make it accessible...