# About this website

Welcome to mtheory.co.uk and our new, albeit incomplete website. The old site was annoying me so much that I’ve decided to push the new one up even though it’s not quite finished. Anyway this website lifts its name from m-theory a branch of theoretical physics.

So what is here? Well mtheory is basically a personal domain used by me (Burly Cumberland) and it also acts as a micro-internet service provider. Various friends and family use it as their primary email accounts and a couple of them host their web pages and other bits and pieces through the site. In order to help them out there is a support section which provides help on services with a strong focus on email. I also have a passing interest in python for scientific use so I plan to move some bits and pieces I have skattered around into one place. To see what has been added since you last visited check out the most recent posts.

But wait there is very little about string theory on this site. Indeed this is true, however back in the late nineties when I was trying to dream up a domain name I happened to be reading the Elegant Universe by Brian Greene and mtheory stuck in my mind and seemed as good a domain name as any other. I’ve been using it since then. I’ve written a brief and probably rather poor description (perhaps David will improve it) of m-theory in case googling again is just to much effort. There are also a couple of links to other pages on the subject.

# What is m-theory

It is rather difficult to explain m-theory in a couple of words but I’ll have go. To understand what m-theory is we need to keep a couple of steps back, perhaps some rather large steps back.

Physics largely attempts to describe the universe and everything in it via mathematical models. Physicists mostly spend their time doing one of two things: trying to work out a mathematical model to describe something or trying to design and conduct an experiment to test a mathematical model. *(This isn’t strictly true, many experimental physicists just ‘try’ out things in their labs which are usually related to what they are working on. Sometimes the results of these, try it and see, experiments produce new and interesting physics which needs to be understood. Often they just don’t work. I expect theoreticians do something similar. The idea that is taught in school: scientist sees problem, thinks up theory, tests theory via experiment isn’t really how science works. It is much more chaotic than that, see this site for a better description.) *As physicists are a productive bunch, there are a lot of models describing a lot of the world. However they are also lazy and nobody really want to learn all these models. Thus there is an idea that perhaps everything can be described and understood via one model, maybe even one equation. This idea is often referred to as the Grand Unified Theory (GUT for short) or The Theory of Everything (TOE for short, one wonders if they wanted another acronym sounding like a body part).(Remember I mentioned that physicists are lazy, well as part of this they like to abbreviate as much as possible, even in their mathematics).

This may sound crazy, how could you possibly describe everything around us via one equation? Well believe it or not, over the centuries there has been some success in merging theories together. Newton’s laws simplified the description of motion and the effect of gravity down to a couple of equations. Maxwell’s equations pulled a description of electricity and magnetism together. Einstein’s theory of relativity is essentially a more general version of Newton’s laws incorporating time and gravity. Quantum mechanics does an excellent job of describing a whole host of things happening on an atomic scale. Perhaps most recently Maxwell’s theory of electromagnetism was unified with the weak force into a single electroweak theory. So all in all there has been progress.

Fortunately there is still much to do, otherwise what would we do with all those physicists? Hence a lot of theoretical physicists spend their time trying to unify other theories, such as general relativity and quantum mechanics in the hope that this will make life easier and provide us with one theory to describe everything. Enter string theory. String theory is an attempt to do just this (there are lots of others such as loop quantum gravity). String theory basically proposes that fundamental particles (the smallest known elements of matter) such as electrons, quarks (which form together to make protons and neutrons) are actually made up of tiny little strings. These strings are vibrating and the different resonances (a bit like notes of a guitar string) are different fundamental particles. This is a wonderfully simple idea, unfortunately though the mathematics is rather complicated. It turns out that different groups of theoretical physicists came up with different variations of string theory. They all have the same core idea but subtle and important differences, a bit like steak with garlic sauce and steak with peppercorn sauce. They both have steak but taste rather different! Anyway this was proving a bit frustrating until some particularly clever physicists got together and realised that all these different flavours of string theory might be derived from one over-arching theory. This theory is called m-theory. Phew. There we go.

Cool. So now you may be wondering that this is great but does it work? I think the answer to that would have to be that we don’t yet no. The math is very hard and there is one odd prediction that makes a lot of people nervous. M-theory requires 11 dimensions, yes 11. That is the familiar three spatial dimensions you know: up-down, left-right, back-forth and time plus 7 others. Whoa, where are they? Well that is what everyone wants to know. The theoreticians believe that these 7 other dimensions are bound up so small that we just don’t see them (the picture to the left is of Calabi-Yau space, an attempt to illustrate these extra dimensions in 3D). In fact they are a similar size to the strings and the strings interact with these dimensions to form everything we see around us. If we could find these extra dimensions then m-theory would gain some experimental grounding. The best hope of seeing any extra dimensions will be at CERN in the Large Hadron Collider. Alternatively if the theory could predict something that other theories can’t which we could test experimentally then we’d know that it might be a good theory. Unfortunately the complexity of the mathematics has made this hard.

In summary then: m-theory is a theory with no current experimental support which attempts to explain everything by describing the world in terms of tiny little vibrating strings in 11 dimensions.

Excellent, where can I learn more? Well try some of these links:

- Brian Greene talks about string theory on TED
- The wikipedia entry
- Brian Greene’s book – The Elegant Universe