The following post is about trying to give a general idea of the Large Hadron Collider experiments being carried out by CERN (and as such, the post is LARGE), better known as the Big Bang experiment. The main motivation behind this is my sister. I don't profess complete knowledge about the subject matter nor do I aim at explaining the technical intricacies involved. I aim at the general non-technical reader. And I hope to enthuse and introduce them to the wonderful world that is physics without the equations that scare most people away. I don't take any responsibility for technical mistakes but I am open to corrections and suggestions.
The Child And His Toy
Most kids love to play with toys, as we did, and some kids end up breaking their toys. Elders might scorn at a broken toy, but ever wondered what made the child break the toy? The thing which made the child break the toy is the essence of every human - "curiosity". Ever since our little brains started working, we, as humans, are constantly pestered by our curiosity about everything. It is curiosity which separates humans from the rest of the animal species (I should add, though, that curiosity is not the sole property of humans, it has been observed in many other animals as well). If I am asked to point out one thing which laid the foundation for the tremendous progress achieved by us, I would pick curiosity and inquisitiveness without second thoughts.
Coming back to the kid and his toy. At such a young age, the brain's curiosity is all-consuming. Not being restrained by the constraints faced by the adults, the brain devotes almost all its capacity to fathom the mysteries surrounding its environment. And a kid's environment is almost entirely filled with toys. When given a toy, he plays with it (cliché) till he gets bored of it. Then he proceeds to find how it works and what it is made of.
To find how it works, the kid must first know what the toy is made of. And how does he know that? He certainly does not google it nor does he read "ingredients", if ever there is something like that for toys. He uses the most rudimentary tools and methods available to him to find out what parts the toy is made of. And the most rudimentary method is : break the toy to find out what's inside it or what it is made of. He will make use of anything in his environment to break the toy, from his mouth to a stone.
The Physicist And His Toy
Let's fast-forward until the child becomes an adult physicist (wonder what made him choose that field when there's the easier and fancier B.Tech). The adult brain might choose a different set of toys this time around, but the rules of the game are still the same: find a toy, play with it, find out what it is made of. Now that he is a physicist, his toys are a bit more sophisticated - atoms, electrons, photons, bosons,mesons, muons, quarks, protons, anti-particles, neutrinos, to name a few.
The toys have changed, but the methods remain rudimentary. Over the course of the century, scientists made extra-ordinary breakthroughs, I repeat, extra-ordinary, in finding out that molecules are made of atoms and atoms, in turn, contain more than a 100 sub-atomic particles. It is no mean achievement, though it might look trivial to us today. Breaking one toy threw up more than a hundred new toys! That's the best part about physics. The never-ending joy of discovery.
The toy : A proton. The aim: Find out its ingredients.
It's trivial to break a toy. Hit it on the ground, hammer it, stone it, a kid can come up with a hundred different ways. Unfortunately, the physicist is poorer with respect to the tools he has at his disposal. One can't use a hammer to break a proton. Nor can one use a stone. So, the BIG question: How to break a SMALL object?
Think about it before you proceed.
Imagine an accident on a highway. May be a car colliding with another car. It's usual for a car on a highway to cruise along at high speeds. When two such cars collide, the results are catastrophic. One can generally see the car shredded into pieces and the various parts of the car lying around. This is the eureka moment. You want to break a proton? Simple, make it collide with another proton at high-speed.
The Choice and the Problems
I'd like the readers to wonder about a couple of things: Why the choice of proton? Why not an electron? Why not a neutron? Do post your views as comments. The following paragraph should lead to the answers.
Being such small objects, they need to be collided at extremely high speeds. And I mean extreme. The speeds at which these particles are colliding at present in the LHC are the order of 99.9% of the speed of light. That's how fast. If you are wondering, speed of light is the speed limit of the universe. However, the real question is: "how do I accelerate these protons to such high velocities???"
It's elementary knowledge that protons are positively charged particles and that any positive charge is attracted by a negative charge. Yes, you are right, we place an electric field in such a way that these protons are accelerated towards it (this is the principle based on which your TV works). And it takes a long time for the protons to reach such high velocities. One can't have these protons travelling in straight lines till they reach sufficient velocity. By that time, they would have crossed the galaxy. Instead, they are kept accelerating in circular paths. Hence, these particle accelerators are called cyclotrons. Ingenious!!
Fasten your seat belts, Quantum Physics approaching
At such high velocities, these particles have tremendous velocities. You know the equation to find the kinetic energy. Do the math. Before that, take this:
According to the laws of relativity, the faster an object travels, the heavier it gets.
So, when you are walking, you are actually heavier than when you are sitting idly. Not just that, when an object is accelerating, it's time slows down. That's quantum mechanics for you. Coming back, what has this to do with our discussion? The energy associated with the protons is not just the kinetic energy. Let me take the liberty of using perhaps the most famous equation:
The proton, when it is accelerated to velocities close to the speed of light, is almost 7,000 (correction made) times heavier than normal. Now calculate the energies involved in the collision. These sort of energies are never before seen in the Universe, except at the beginning of the Universe itself.
That let's us peek into the beginning of the universe. The experiments aim to recreate the conditions existing at the time of the creation of the universe. The scientists also aim to find a particle called "Higgs Boson". The media calls it "The God Particle." It is common knowledge that electrons are responsible for the negative charge. More the number of electrons, greater the negative charge. Similarly, greater the number of protons, greater the positive charge. The spin on these particles gives rise to magnetism. But, what gives a particle its mass? The standard model predicts that the god particle gives a particle its mass.
Here's a link to an excellent video explaining the experiment in detail: http://www.cse.iitm.ac.in/~chandrah/cern.wmv
I can't wait to see the results and the implications. Thanks for bearing with the length of the post.
Hey, this is officially the end of the post. I am just posting some trivia
- Boson is named in honour of an Indian scientist (so rare these days), S N Bose
- Higgs Boson is named after Peter Higgs
- The term Big Bang was first coined by Fred Hoyle, an astronomer extra ordinary.
- The LHC produces 15 petabytes of data per year
- ECIL, Electronics Corporation of India, supplied parts of the LHC
- Physicists from the University of West Bengal are part of the experiment
- The faster you move, the slower your time travels - GPS satellites make use of this.