Skip to main content

Quantum Space: Jim Baggott *****

There's no doubt that Jim Baggott is one of the best popular science writers currently active. He specialises in taking really difficult topics and giving a more in-depth look at them than most of his peers. The majority of the time he achieves with a fluid writing style that remains easily readable, though inevitably there are some aspects that are difficult for the readers to get their heads around - and this is certainly true of his latest title Quantum Space, which takes on loop quantum gravity.

As Baggott points out, you could easily think that string theory was the only game in town when it comes to the ultimate challenge in physics, finding a way to unify the currently incompatible general theory of relativity and quantum theory. Between them, these two behemoths of twentieth century physics underlie the vast bulk of physics very well - but they simply can't be put together. String theory (and its big brother M-theory, which as Baggott points out, is not actually a theory at all but simply a conjecture) has had much written about it. But the main alternative theory, loop quantum gravity has had far less coverage. As I mentioned in another review (and Baggott also picks this up), in one whole book on gravity, loop quantum gravity is only mentioning in an endnote. Yet in many ways, loop quantum gravity has a lot more going for it than string theory.

One major strand of Quantum Space is a biography of two key players in the field - Lee Smolin and Carlo Rovelli, both good writers for the general public in their own right, but neither has been able to come close to what Baggott does in trying to make the ideas of loop quantum gravity accessible at a deeper level than a summary, hand-waving description. It’s also the first complete and approachable account I’ve seen of how both approaches to a quantum theory of gravity were derived. The only downside of the way it's structured is that I think if you’re going to be comfortable with the level of detail Baggott gives, you probably don’t need the first 100 pages or so giving background on quantum theory and general relativity.

My only real concern apart from that unnecessary opening material, which makes the book a little too long for my tastes, is that there could have been more unpacking of how loop quantum gravity represents reality - the jump from the introduction of spin networks to anything resembling a theory that can be applied to a real world where things happen is overwhelming. I had to resort to the much valued advice of one of my supervisors at university who said 'Don't worry if it doesn't all make sense, just keep on with it and hopefully it will all come together.' It almost all did all come together, but I was left with a nagging doubt that I couldn't really grasp the foundation of the whole idea.

As well as coming out of reading this book with significantly more respect for Rovelli (whose popular science writing I find flowery and overrated), I feel that Baggott has done a huge favour for anyone who really wants to understand modern theoretical physics, giving a much better understanding of this fascinating attempt to deal with a central requirement to explain the workings of our universe. It's a triumph.
Hardback:  

Kindle:  
Using these links earns us commission at no cost to you
Review by Brian Clegg
Labels:

Comments

Post a Comment

Popular posts from this blog

Mathematics with Love – Mary Stopes-Roe *****

Admittedly it’s early days (this review is written in January), but this, for me, is the surprise hit of the year so far! I approached this book with trepidation, but found it absolutely delightful. It is described on the cover as the “courtship correspondence of Barnes Wallis, inventor of the bouncing bomb”, and contains a series of letters between Wallis and his cousin and eventual wife Molly Bloxham, along with some useful annotation by their daughter, Mary. The courtship itself is not without difficulties, as Wallis was 18 years older than the 17-year-old Molly at the start of the correspondence, and her father, not surprisingly, wasn’t too pleased about the interest of such an elderly suitor, but that isn’t the only reason the letters are interesting – it’s also because of maths, and Wallis’s position in the UK as the engineering hero of the Second World War. (Incidentally, it seemed very strange to see letters addressed to “Barnes” – I had always assumed Barnes Wallis was a ...
Post a Comment
Read more

Why Nobody Understands Quantum Physics - Frank Verstraete and Céline Broeckaert **

It's with a heavy heart that I have to say that I could not get on with this book. The structure is all over the place, while the content veers from childish remarks to unexplained jargon. Frank Versraete is a highly regarded physicist and knows what he’s talking about - but unfortunately, physics professors are not always the best people to explain physics to a general audience and, possibly contributed to by this being a translation, I thought this book simply doesn’t work. A small issue is that there are few historical inaccuracies, but that’s often the case when scientists write history of science, and that’s not the main part of the book so I would have overlooked it. As an example, we are told that Newton's apple story originated with Voltaire. Yet Newton himself mentioned the apple story to William Stukeley in 1726. He may have made it up - but he certainly originated it, not Voltaire. We are also told that ‘Galileo discovered the counterintuitive law behind a swinging o...
Post a Comment
Read more

On Time - Jim Al-Khalili *****

By a small margin Jim Al-Khalili's The World According to Physics is my favourite of his books, both because the 'three pillars' concept at its heart works so well - but also because it's short. On Time is somewhat heavier, but thankfully not a wrist-buster. It might seem at first sight odd that a book on a subset of physics is considerably longer than one covering the whole thing, but time is one of those subjects that inevitably involves considerable complexities and needs depth. As Al-Khalili establishes, it's hard to think of any other scientific concept where our perception of it - what he refers to as manifest time or psychological time - is so different from the view from physics. Some physicists go so far as to suggest that time doesn't exist at all. In the book, Al-Khalili sets out (to my mind quite successfully) both to explain why they think this is the case, but also why it's not the best interpretation of time. I'd certainly note that I...
Post a Comment
Read more