I have just got back from co-chairing a scientific workshop in Switzerland. It was great, hard work, but great. Togther with the other workshop chair, Paddy Royall, we had invited scientists to come from places as far away as Tokyo in Japan, and Houghton, which is a small city on Lake Superior on the border of USA and Canada, and they’d come. The theme of the conference was crystallisation, but the speakers talked about crystallisation in many different contexts, from water droplets freezing in the atmosphere, to chocolate, and to crystallisation as a switch in advanced flash memory.

Our workshop had a conference dinner, and over some sea bream with risotto, and a melting-middle chocolate pud, I learnt some fascinating things about the Earth’s atmosphere. The one that really struck me is that the current of a lighting bolt comes from a volume of cloud that can be a hundred cubic kilometres. The electric current within the cloud that funnels into a single lightning bolt is distributed over a tree-like structure of electric currents that can spread over a cloud area of many square kilometres and go up several kilometres.

In a thundercloud the charge in each cubic metre is small – after all a cloud is just a very dilute aerosol of small water droplets and/or ice crystals. But over the cubic kilometres aka billions of cubic metres there is enough charge to generate the huge power of a lightning bolt.

As clouds are always up the sky far away from us, I don’t think we realise how big they are. This reminds me of one of my favourite Father Ted clips, in which Father Ted tries to explain to Father Dougal why the cows in a distant field look the same size as toy model cows:

Anyway, coming back to the point I was making, when I was tucking into the conference dinner, and learning fascinating things about our atmosphere, it felt a real privilege to be a scientist.