Twenty Worlds - Niall Deacon *****

This is a truly entertaining and informative book, but the reason I’m giving it the full five stars has as much to do with the refreshing novelty of the author’s style as anything else. There’s novelty in the subject-matter too – the wide variety of recently discovered exoplanets orbiting other stars – but even so this is the third book on the topic that I’ve read. The first two were a lot less fun to read, and (without naming and shaming the authors) it’s worth a brief diversion to explain why.

The first author was a university professor with a vast knowledge of the subject, who seemed determined to convey the entirety of that knowledge without stopping to think whether it was interesting or necessary for a general audience. The second author – another academic – took a different but equally tedious approach, with a plodding chronological account that focused as much on the dull routine of the scientists involved as on their work.

Niall Deacon doesn’t make either of those mistakes. He’s a professional astronomer too, though you wouldn’t guess that from his writing style, which is as straightforward and lucid as science writing gets. Each of his 20 chapters is focused, not just on a single planet, but on one or two interesting new things about it. This gives him more space to get the key points across, without cluttering up the picture with peripheral detail. It’s this lack of extraneous detail that gives the book a different feel from the usual run of popular science books. We’re rarely told, for example, the date that a particular planet was discovered or the names of the researchers involved (although these can be surmised from the list of references at the end).

Deacon’s narrative style is unconventional, too. New scientific ideas are approached by an oddly lateral route, starting with a seemingly random, everyday metaphor and then gently easing the reader towards the point he’s trying to make. So you get chapters starting with anything from Ramadan or the Beatles or David Attenborough to frisbees, vaccinations and mountain lakes. I  found this rather bemusing at first, but once I got used to his style it was fun trying to guess where he was going with an idea.

The fact that there’s at least one new idea per chapter means the book’s emphasis is on breadth and variety – not just of the exoplanets themselves, but of how they were discovered. A few of the more obscure ones were new to me, despite my previous reading on the subject. I didn’t know exoplanets had been found using gravitational microlensing, for example – or that, with hindsight, evidence for a planet orbiting van Maanen’s star may have been found more than a century ago. I was also delighted to learn about WASP – Britain’s low-budget answer to the Kepler space telescope, consisting of an array of Canon telephoto lenses purchased on eBay and installed on a mountain in the Canary Islands.

When I saw the word ‘worlds’ rather than ‘planets’ in the book’s title, I assumed the focus would be on potentially habitable, Earth-like planets. But if anything, the opposite is true. To use Deacon’s analogy, beginning a planet hunt by saying ‘let’s look for another Earth’ is a bit like British tourists in an exotic far-flung destination saying ‘let’s find a fish and chip shop’. I’m aware of three or four well-known exoplanets that are often mooted as possible ‘other Earths’ that he doesn’t even mention. But to do so would risk turning the book into a boringly repetitive catalogue – and happily it’s the exact opposite of that.

Hardback:    

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Review by Andrew May