WHAT BANGED?

I had an interesting conversation with my daughter the other day. We were talking about religion and got onto the subject of the Big Bang.

I understand the idea behind the Big Bang, since I am a mathematician by training and my special subject at university was relativity. We can prove that the universe is expanding; so if we wind the clock back, it must at one point have been very small. Infinitessimally small, to use the jargon. Furthermore, since the universe is now very large, the bang that made it thus must have been pretty big. So, Big Bang is not an unreasonable description.

But, but, but. Although I could once (though no longer) "do the math", I have always had a somewhat more philosophical problem. Namely, what exactly was it that banged? I must admit that I have no idea.

Have you? Please post your answers below. The ten best ideas will go into the Walter Blotscher Big Bang prize draw. The winner will get a custom-made Hadron collider, which I promise to build in their garden, once the Smug Builder project is finished. Now there's an incentive.

Walter Blotscher