Skip to main content

Mass - Jim Baggott *****

Jim Baggott is one of the UK's best popular science writers and never disappoints. As the book's name suggests, Mass is about what seems at first sight a straightforward and ordinary aspect of matter. It's just a property that stuff has that makes it behave in a certain way. But the further we get into the book, the less obvious the nature of mass becomes - as a reader, it can feel a little like following Alice down the rabbit hole.

We begin with a run through the history of our growing understanding of what matter is, and the nature of mass. Apart from repeating the myth that Giordano Bruno was burned at the stake for supporting a heliocentric cosmology, this is fairly straightforward stuff, but then Baggott makes the interesting step of not just making the transition from a philosophical view to a scientific one, but continuing with the philosophy to include, for example, Kant's 'Ding an sich' or 'thing-in-itself' concept that underlines the way that we can't actually know reality, only our sensory responses and the models we build. There was a time when scientists were on the attack as far as philosophy is concerned (Stephen Hawking infamously declared philosophy to be 'dead' in The Grand Design), but in practice, with a concept like mass, that philosophical consideration is important and useful.

As he continues, Baggott takes us through relativity and its implications for mass to be dependent on frame of reference and quantum theory to underline our growing understanding of what stuff is, before coming to his coup de grace, where we find that mass is not that fundamental aspect of stuff that it appears to be, but is rather a combination of the interaction of quantum fields and an effect produced by energy. It's a neat inversion of our usual way of looking at mass and matter - beautifully well presented. Along the way, Baggott manages his usual trick of going into the physics to a slightly deeper level than is common in popular science coverage - for example, in his description of what is involved in the renormalisation used to get rid of infinities from quantum electrodynamics - while keeping the text mostly approachable.

If I have any criticism, I felt the skip through relativity didn't quite do the subject justice. It was too summary to really get a feel for it, but too detailed to be scene setting, making it one of the less interesting parts of the book, particularly if you've read anything on relativity before. That balance seemed to be handled better with quantum theory. I'd also say that towards the end, where we get into abstruse matters, there isn't quite enough explanation, so the reader is occasionally left thinking 'I don't see how you make that leap.' This seemed particularly true when talking about spontaneous symmetry breaking. There's a diagram showing how ice has lower symmetry than water that confuses rather than helps, and we are told that for spontaneous symmetry breaking to occur when water freezes 'we need to add something (impurities or inhomogeneities, in this case) to encourage it to happen.' A very reasonable reader response is 'If you have to add something, it certainly isn't spontaneous' - a problem that isn't addressed.

Despite a few points like this towards the end, for me the book was interesting throughout (I liked the business book style 'five things we learned' at the end of each chapter) and it encourages the reader to really think about the nature of matter and how something as apparently straightforward as mass is not what it seems. That delight in revealing the unexpected typifies, for me, the joy of physics.


Review by Brian Clegg


Popular posts from this blog

The Feed (SF) - Nick Clark Windo ****

Ever since The War of the Worlds, the post-apocalyptic disaster novel has been a firm fixture in the Science Fiction universe. What's more, such books are often among the few SF titles that are shown any interest by the literati, probably because many future disaster novels feature very little science. With a few exceptions, though (I'm thinking, for instance, The Chrysalids) they can make for pretty miserable reading unless you enjoy a diet of page after page of literary agonising.

The Feed is a real mixture. Large chunks of it are exactly that - page after page of self-examining misery with an occasional bit of action thrown in. But, there are parts where the writing really comes alive and shows its quality. This happens when we get the references back to pre-disaster, when we discover the Feed, which takes The Circle's premise to a whole new level with a mega-connected society where all human interaction is through directly-wired connections… until the whole thing fails …

Everything You Know About Space Is Wrong - Matt Brown ****

What we have here is a feast of assertions some people make about space that are satisfyingly incorrect, with pithy, entertaining explanations of what the true picture is. Matt Brown admits in his introduction that a lot of these incorrect facts are nitpicking - more on that in a moment - but it doesn't stop them being delightful. I particularly enjoyed the ones about animals in space and about the Moon.

Along the way, we take in space exploration, the Earth's place in space, the Moon, the solar system, the universe and a collection of random oddities, such as the fact that Mozart didn't write Twinkle, Twinkle Little Star. Sometimes the wrongness comes from a frequent misunderstanding. So, for example, Brown corrects the idea that Copernicus was the first to say that the Earth moves around the Sun. Sometimes there's some very careful wording. This is used when Brown challenges the idea that the Russian dog Laika was the first animal in space. What we discover is that, i…

Dark Matter and the Dinosaurs - Lisa Randall ****

I did my PhD in galactic dynamics - which is an awkward subject when people want to know what its relevance to the 'real world' is. So I was excited when Clube and Napier's book The Cosmic Serpent came out, around the same time, because it provided me with a ready-made answer. It argued that the comets which occasionally crash into Earth with disastrous results - such as the extinction of the dinosaurs - are perturbed from their normal orbits by interactions with the large-scale structure of the galaxy.

I was reminded of this idea a few years ago when there was a flurry of media interest in Lisa Randall's "dark matter and the dinosaurs" conjecture. I was sufficiently enthusiastic about it to write an article on the subject for Fortean Times - though my enthusiasm didn't quite extend to purchasing her hardback book at the time. However, now that it's out in paperback I've remedied the situation - and I'm glad I did.

Dark matter is believed to exi…