Structure is a fine thing

Atoms are pretty small things, but they can still get excited, albeit in a very controlled way.
What atoms do to show their excitement is to send out light, but light that is restricted to very particular colours. We all know the characteristic yellow of sodium lighting, try throwing a bit of salt on a gas ring and the same yellow briefly appears. Strictly speaking it isn’t just light that is emitted but radiation. Radiation in the microwave, infra-red and higher frequencies is there too, as well as ultra-violet and even x-rays, given sufficient energy to do the exciting.
Scientists got quite excited too when this phenomenon was first noticed, because each element, iron, hydrogen, carbon and so on all give out different frequencies, different colours if you like, so that each different atom has a unique signature. Suddenly they didn’t have to capture something, stick it in a test tube and torture it to find out what it was. They could just look for the signature when the stuff was heated, like in a star. When those scientists started looking at the sun, they found a signature they’d never seen before and decided it must be being given off by a new element, which was given the name Helium, since found in small amounts on Earth and used to make diving safer and to make your voice go all funny and high-pitched at parties.
Then someone started looking more closely at the “spectral lines”. The light from a load of excited atoms is split up and recorded on a long, thin photograph; the different colours appear as lines, hence the name. Anyway, it turns out that the lines have a width, and different lines had different widths, line by line and atom by atom; this phenomenon is called “fine structure”.
There is a lot of rivalry between experimental and theoretical scientists. The experimental ones like to find new things that the theory guys haven’t predicted and the theory people like to send the experimenters off to look for things that no-one has found yet. This time the experimenters were way ahead, with the theorists having a lot of catching up to do, but eventually they cracked it and worked out some mind-numbing formulae that predicted the behaviour of the spectral lines and in particular the fine structure. In doing so they made use of a constant, the fine structure constant.
Now that in itself isn’t very strange. There are lots of constants, things whose size have to measured rather than worked out theoretically, in our universe, the speed of light and the charge on an electron for example. The fine structure constant, however, is a bit special, it’s a number with no units attached. The speed of light, for example, needs centimeters per second to qualify the number, but the fine structure constant just is, well, a number.
The fact that scientific theories have lots of constants in them worries some people, they’d like to know why the constants are the size they are and maybe even derive them from other, deeper theoretical ideas. This has spawned an interesting set of discussions and researches into how much these different constants could vary, without the universe as we know it being affected much. When that is done, rather interesting conclusions get arrived at, specifically, some of them have to be pretty much the size they are, and the most crucial found so far is our new friend, the fine structure constant. Learned scientists claim that if it changed by as little as 4% our universe would just not work!
I can only think of two possible conclusions to that, one is that the chance of our universe happening by accident was very, very, small indeed and the other is that something designed it and set it going. I’m still trying to work out which is the more terrifying.