Skip to main content

Once Before Time – Martin Bojowald ***

Physics has a dark secret at its heart. The two big theories that form the main basis of just about everything don’t work together. Quantum theory, dealing with the very small, and general relativity, dealing with gravity and the nature of space-time, are incompatible. Not only does this make it impossible to put together a coherent theory covering, for instance, all forces, it messes up our understanding of events that fit into both camps, like the big bang.
The best known modern attempt to pull the two together is string theory – but this has huge problems as far as making useful predictions goes, and some regard it as a dead end. Its main opposition (though there are other theories) is loop quantum gravity. This breaks down space-time itself into atoms, which have something of a loop-like nature, making reality a kind of weave of these loops.
This theory too has yet to make any useful predictions, and like string theory it depends on mind-twistingly complex maths. Yet it is in some ways simpler, doesn’t need many extra dimensions to make it work and even gets around some of the concerns about infinities cropping up at the big bang.
This means we desperately needed a good, popular science guide to string theory – and sadly we still do. Martin Bojowald is one of the key figures in the field, and certainly has a good grasp on the science, but has real problems with getting the information across. It probably doesn’t help that this book was first written in German, then translated into English by the author – certainly at times you might think it still isn’t English.
The science simply hasn’t been made understandable. The author spends a fair amount of time, for example, on Penrose diagrams. These special space-time diagrams are very useful to help understand what is happening in a black hole and similar oddities of space time. But it is very difficult to grasp what is going on. We are told that the singularity is not timelike, but spacelike – it is part of evolving space at a fixed time. This is shown clearly on the diagram, but we are given no real explanation of why this is so, or what it means.
It doesn’t help that the book is illustrated by fairly meaningless arty photographs and has occasional snippets of very bad fiction (which presumably are harder to translate than the science). All in all it is a frustrating read that is unlikely to be illuminating unless you already know quite a lot about the subject area, but not about loop quantum gravity.
Hardback:  
Also on Kindle:  
Review by Martin O'Brien

Comments

Popular posts from this blog

Beyond Weird - Philip Ball *****

It would be easy to think 'Surely we don't need another book on quantum physics.' There are loads of them. Anyone should be happy with The Quantum Age on applications and the basics, Cracking Quantum Physics for an illustrated introduction or In Search of Schrödinger's Cat for classic history of science coverage. Don't be fooled, though - because in Beyond Weird, Philip Ball has done something rare in my experience until Quantum Sense and Nonsense came along. It makes an attempt not to describe quantum physics, but to explain why it is the way it is.

Historically this has rarely happened. It's true that physicists have come up with various interpretations of quantum physics, but these are designed as technical mechanisms to bridge the gap between theory and the world as we see it, rather than explanations that would make sense to the ordinary reader.

Ball does not ignore the interpretations, though he clearly isn't happy with any of them. He seems to come clo…

The AI Delusion - Gary Smith *****

This is a very important little book ('little' isn't derogatory - it's just quite short and in a small format) - it gets to the heart of the problem with applying artificial intelligence techniques to large amounts of data and thinking that somehow this will result in wisdom.

Gary Smith as an economics professor who teaches statistics, understands numbers and, despite being a self-confessed computer addict, is well aware of the limitations of computer algorithms and big data. What he makes clear here is that we forget at our peril that computers do not understand the data that they process, and as a result are very susceptible to GIGO - garbage in, garbage out. Yet we are increasingly dependent on computer-made decisions coming out of black box algorithms which mine vast quantities of data to find correlations and use these to make predictions. What's wrong with this? We don't know how the algorithms are making their predictions - and the algorithms don't kn…

Five Photons - James Geach ****

It is generally acknowledged that Stephen Hawking's A Brief History of Time is one of the most common books to be bought but not read beyond the first few pages. If you are the kind of popular science reader who found Hawking hard going, you can stop now - Five Photons is not for you. If, on the other hand, you found A Brief History of Time a piece of cake and wished you could get into more depth without resorting to heavy mathematics or a tedious textbook style, Five Photons could be just up your street.

Astrophysicist James Geach starts of fairly gently with a chapter on the nature of light that mostly sets aside quantum physics, leading up to the observation that light is our vehicle for for stripping back the history of the universe to its earliest times (or, at least, the point where the universe became transparent). From here on, the five photons of the title take us on different journeys, from the oldest surviving light of the cosmic microwave background radiation to that fr…