Musical Notes and the Universe of String Theory
(Article Originally Published 27/11/2012)
“You are the music while the music lasts.”
When you pluck a guitar string a sound wave is produced that vibrates the air molecules producing a musical note that you hear. Imagine that the universe around you is the product of a similar vibration. That’s what string theory is all about.
Picture the smallest known building block in the universe, smaller than an atom, smaller than an electron, smaller than a quark, and peer inside any of these and you’ll see a dancing filament of energy called a string. Just how small are we talking about here? Well, if you scaled up a hydrogen atom to the size of the universe, the string inside it would only be the width of a human hair.
Why the need for string theory at all? After all don’t we have Einstein and his theory of gravity that accurately deals with very large objects such as planets and stars? We have quantum mechanics which explains what happens with the very small. However, the problem for physicists is that these theories can conflict with each other. There are also shortfalls in these theories that tell us that we don’t fully understand how the cosmos works. For example, Einstein’s gravity theory simply can’t cope with what happens inside the extremes of a black hole. Therefore the search has been on for a theory that ties everything together has been on – sometimes referred to as the grand unification theory. Step centre stage and meet the candidate that attempts to unify the very large, the very small, gravity, and even time itself – string theory.
All particles around us go through four basic interactions: gravitational, electromagnetic, strong nuclear interactions, and weak nuclear ones. Einstein covered gravity, and quantum mechanics dealt with the rest, but string theory attempts to tie everything together.
String theory suggests that when a string vibrates, unlike a guitar string producing musical notes, particles are actually created. Also, by changing the frequency of the string, any sort of particle can be made. It’s an elegant theory, but for the maths behind it to work, it requires more dimensions than the four we can currently observe. In addition, at the heart of string theory, is the idea that gravity is a particle that we have so far failed to detect, the graviton. This particle is also predicted by quantum theory, as was the Higgs Boson, whose existence now looks confirmed by the Large Hadron Collider (LHC) in Geneva. The graviton is another juicy boson and there is a chance that the LHC may be able to confirm its existence as well.
If string theory is proven to be correct, it may answer questions that have baffled science for some time such as black holes, the existence of extra dimensions, dark matter and dark energy; and even the origin and fate of our universe itself. And it may be that the LHC provides the stepping stone towards confirming string theory’s credentials.