REVISIT SERIES: A post from July 2013 -  I've written two books about infinity, notably A Brief History of Infinity , and it's a subject I enjoy writing and thinking about. But for physicists, infinity often means a problem. While we can conceive that the universe might be infinite, because we only ever deal with a part of it, when infinity rears its head in calculations, it usually means trouble. This most famously arises in quantum electrodynamics, the science of the interaction of light and matter on the quantum scale. The solution there has been renormalisation - in effect, putting in the real observed values of some quantities to make the infinities go away. And this works, but it's a bit uncomfortable. Elsewhere, such as at the moment of the big bang or in the heart of a black hole, the infinities are taken to mean that our current theories break down at that point and we need to find new ways to look at what's happening. However, there is another class of infinit

When I was in my last year at Cambridge, by which time my Natural Sciences degree had been refined down to experimental physics, I had to do a project. I had always been fascinated by radio astronomy, often passing Jodrell Bank on the way to a friend's house when at school: with a fellow student I was offered the chance to try some basic radio astronomy. We weren't given a handy, off-the-shelf, giant steerable dish, though. We had to start from scratch. One huge advantage I had in teaming up with Dave Izod (apologies if I got the name wrong - it was a long time ago) was that he had the huge advantage of being a (then) rare undergraduate with a car. The Mullard radio astronomy observatory was over four miles from my college and I didn't have a bike.  One of the reasons the exercise was so satisfying was that it involved picking up a whole range of new skills. The starting point, for example, was using a theodolite to determine levels before partially constructing and deployi

REVISIT SERIES: A post from July 2012 -  Science isn't always great at naming things. For every photon there are plenty of clunky names that don't do a lot for you. Take, for instance,  the 'principle of least action', which sounds like a description of the lives of teenagers. This is a shame because it is really interesting. For reasons that will become clear I like to think of it as 'the Baywatch principle.' And what it says, in essence, is that nature is lazy. French mathematician Pierre de Fermat used the principle of least action to explain why light bends as it moves from a thinner to a thicker substance (from air to glass, for instance) – and Richard Feynman made it a fundamental part of quantum electrodynamics. The principle of least action describes why a basketball follows a particular route through space on its way to the basket. It rises and falls along the path that keeps the difference between the ball’s kinetic energy (the energy that makes it mov

REVISIT SERIES: A post from July 2014 -  Each week I'm going to include a post from years ago that I feel is worth revisiting: I feel the strong urge to share with you what may be the worst piece of science-based reporting I've seen this year. It's from UK free newspaper Metro and it is titled  Red head? Climate change could make you and your ginger compatriots EXTINCT . (The usually respectable Independent also covered this 'story.') It may not be obvious now, but as the slightly younger picture of me above demonstrates, I am a member of this apparently endangered grouping. But what does the story say exactly? I will extract some of it's joyfulness, so you don't have to read it (though admittedly in the original you get a picture of Lily Cole rather than me). The suggestion is that due to climate change and the 'rapidly increasing temperature across the British Isles, the red hair gene could soon be a thing of the past.' And the way we are

In a recent article , the redoubtable comedian David Mitchell noted that the office supply company Toner Giant had published research showing that a high percentage of those working from home (yes, it was WFH not WTF) watch daytime TV. Sadly, as is often the case when the media comments on data, Mitchell did not provide a link to the original source - it's here if you want it . There are two interesting bits to this - one is what people allegedly watch and why Toner Giant is telling us (Mitchell struggles to understand why they did this, presumably because he didn't read the whole original piece, which tells you) - and the other is whether or not this is a problem. The claim is 82% of UK hybrid workers admit to watching TV when working from home - this is based on a 'survey of 2,000 British hybrid workers', though we aren't told how they were selected and hence how representative they were (or weren't). Why does Toner Giant care? Because they claim that personal

P. D. James was one of the great English crime writers, with one of the more interesting detectives in Adam Dalgliesh, but reading this novel from 1972 I was struck by how interesting it was to me for two reasons. One is purely personal - it's set in Cambridge just a couple of years before I was there, so comparing the picture James paints with my own experience was fun. But more significant is the stylistic approach she takes. I'm a great fan of Margery Allingham - and the central character in James' book is a pure Allingham heroine - Cordelia Gray is young, feisty, intelligent and taking on a role that would in earlier years have been considered the 'unsuitable job for a woman' of the title - a private detective. Although technically an Adam Dalgliesh book, we only get indirect references to him until the final chapter where he makes an appearance, very much as a supporting character. But it's not really having a murder mystery where the author's detective