Time Travel for Beginners – Mary & John Gribbin ****
Although this is a children’s (or more accurately young adults’) book, it works reasonably well for adults too who want a basic overview of the science of time travel. It clearly is aimed at the teen market – it has biggish print, large line spacing and some rather gratuitous illustrations – but it also provides a very effective introduction to the basic physics of time travel.
After a quick introduction to relativity and quantum theory – the basics for any time travel device, the Gribbins plunge into time machines that work by dragging space-time, and time machines based on wormholes. I’m not sure they get wormholes quite right – the wormhole described here is bi-directional, implying it’s a pair of black holes rather than a black hole and a white hole, so it’s not quite obvious how you ever get out of it. But that apart, the basics are fine.
Most young readers will find it fascinating that time machines are not physically impossible, just very, very difficult to build, and the book should do well if the right people get hold of it. My only worry there is that to be old enough to understand this book, you probably will be able to read adult popular science. And if you are reading adult popular science, you probably won’t want a book from ‘Hodder Children’s Books’ that looks like a kid’s book, even though the text is, as mentioned, entirely suitable for a beginner adult.
I also found the last section, which woffles on about sum over histories for time travel a little confusing, as if the authors felt they had to include it, but weren’t sure quite what to do with it.
Overall, though, an effective introduction to the science of time travel.