String TheoryWeird enough to be true?
You may have heard about String Theory and glazed over trying to understand it, so here's a brief explanation that may hopefully help to clarify it...
Basically it means that all the elementary particles such as as Quarks and Leptons that we can detect in particle accelerators like the LHC are actually just one 'visible' point on a string of pure energy. Imagine a guitar string where someone has put a tiny little dot somewhere on the string using luminous paint. You pluck the string with the lights on and you can see the whole string vibrating. But when you put the lights off and it's completely dark all you can see is a tiny vibrating dot.
So the idea is that when we detect a very elementary particle in the LHC for example, what we are actually seeing is just that one 'visible' dot that is actually vibrating on a string of energy.
But why should we bother complicating things by suggesting an 'invisible string' that no one has ever detected?
The major advantage that string theory has over most other explanations about the quantum world is that it actually allows for that strange force we call gravity. It predicts that there could be a particle that has no mass and a type of behaviour called two units of spin. And guess what? That's an exact description of what we think a particle of gravity, a graviton, should be like.
So that's why particle physicists continue to see string theory as a very strong candidate for the solution to everything - the so called Grand Unified Theory.
The problem with string theory is that it predicts that there must be far more than the 4 dimensions in which we live and take for granted. Our 3 dimensional world plus the 4th dimension of time can't explain strings and we find that we have to allow for many other dimensions. The current thinking is that there may be 10 dimensions...
So the world we inhabit relies on just those precise points on the 'string' and not on any of the other places or dimensions that the string covers. Ever wondered why a musical note can sound 'right' or 'wrong' to you, when it is just a noise after all?
Perhaps that's also the case in everything around us and we only accept the stuff that feels right to us...
Note: the actual length of these strings could be incredibly small - just a tiny fraction of the width of an atom.