A guest post by cosmologist Andrew Pontzen, on his experience with us at the Green Man festival in Wales.

I’d like to begin by thanking a cafe in Cambridge. It lends, free of charge, umbrellas to its patrons. Not just any umbrellas: these are the kind of ten-feet-wide uber-umbrellas that you don’t want to be stuck walking behind.

Now, it’s true that umbrellas are more-or-less all the cafe has going for it. In fact, I’m not about to take back the umbrella, mainly because I can’t face going back to the cafe. But nonetheless, that cafe made a crucial contribution to my enjoyment of this year’s Green Man Festival in Wales. I just wanted to acknowledge that up-front.

Normally I don’t bother with umbrellas. Unwieldy. A simple coat will do. But when Wales has rain, it seems, it’s not just any rain: it’s the kind of rain that drenches you in less than a minute. It’s the kind of rain that a raincoat just can’t protect against. It’s the kind of rain, in short, that only a ten-foot uber-umbrella can combat.

And now I have such an umbrella in my car, waiting for the post-apocalyptic day when I’ll revisit ‘cafe underwhelming’ for the last remaining undercooked baked potato in existence. (I will return the umbrella then.)

Talking about science to small groups at a music festival sounds crazy until you consider the possibility of talking to small groups about science at a music festival in the pouring rain, while using an iPad to show pictures and an iPod to play Lewis Dartnell and Guerilla Science’s ‘Sounds of the Universe’. While walking through the mud next to Mia (in a spacesuit painted in water-soluble shiny paint). After delivering an introductory talk in a yurt tent powered by people pedalling on static bicycles.

I am amazed, amazed, that people put up with it. In fact, they didn’t just put up with it: they were enthusiastic; they wanted to know more; they wanted to discuss the geometry of spacetime; they even wanted to hold my umbrella. Not to steal it, you understand, just to hold it while I fumbled around looking for another picture on my iPad.

So I can honestly say the Green Man Festival was as much of a learning experience for me as for those brave souls who tried to listen.

Mind you: having struggled through 36 hours of pouring rain, we were treated to an appearance of the Sun. Then it turns out that iPad screens are so insanely shiny that no-one can see a thing on them. It’s the first time I’ve been upstaged by anyone (in this case, Lewis Dartnell) bringing a stack of paper with images printed on it. “This might work better”, he said.

But when it started to rain again, he didn’t have an umbrella. I did.