Book reviews: The Grand Design | Cycles of Time

Published on Tuesday 14 September 2010 12:35

THE GRAND DESIGN BY STEPHEN HAWKING & LEONARD MLODINOW Bantam, 208pp, £18.99 CYCLES OF TIME BY ROGER PENROSE The Bodley Head, pages 320pp, £25

Just like buses, you wait ages for a new book from an eminent physics professor attempting to explain the origins of the universe, then two come along at once. It's a typical publishing industry quirk that in the same month we should have books from two leading lights in the international physics community, Stephen Hawking and Roger Penrose.

Hawking's book, The Grand Design, is co-authored by scientist Leonard Mlodinow, also a successful and popular science writer, a fact which may explain the difference in tone between it and Penrose's book.

Despite the obligatory grandiose subtitle on the cover ("New Answers to the Ultimate Questions of Life"), the book doesn't contain much new physics, but it does serve as a lucid and concise summary of where the science community is with respects to the origins of the universe.

Rounding up the work done in the 100 years since Einstein's breakthroughs in relativity and quantum mechanics, The Grand Design traces the attempts to reconcile the various theories with each other and with data being collected from laboratories and the far-flung reaches of the universe.

The main problem has been to combine the theories for the sub-atomic quantum world with the physics of huge dimensions of time and space, and it has to be said that the current best fit, M-theory, wouldn't seem entirely satisfactory either to Einstein, who began the quest for a unified theory of the universe, or to the average layperson.

Essentially M-theory is a hotchpotch of models that cover the universe under different specific conditions and which overlap to give similar results. There are two quirky offshoots of this theory. The first is that we live in an 11-dimensional world, ten of space and one of time, except seven of the spacial dimensions are tiny, curled in on themselves and undetectable. The other is the fairly familiar multi-verse idea, that an infinite number of universes are being created all the time and that, again, we just can't detect them.

Throughout it all the tone is light, but the authors are keen to emphasise that the big questions on the book's jacket are essentially meaningless, and we need to have a shift of perception to understand the universe as it was at the start. This is best summed up with a neat analogy near the end, where the question "what was there before the big bang?" is compared to "what's south of the South Pole?".

While The Grand Design contains nothing you wouldn't read in an undergraduate physics textbook - and contains not a single equation - Roger Penrose's Cycles of Time is more akin to an academic paper; it's littered with complex equations, diagrams and ideas.This reviewer has a PhD in nuclear physics, but I struggled to keep up.

Having said that, it does at least contain a genuinely new idea about the origins of the universe that, although untested, seems to hold together theoretically and must be taken seriously given Penrose's status.

Penrose takes the Second Law of Thermodynamics and applies its statement about increasing entropy or "disorder" to both the origins and eventual demise of our universe. And what seems to pop out, after a lot of brain-frying mathematics, is that the two extremes are indistinguishable. Penrose's theory of Conformal Cyclic Cosmology seems to point out that at the start of the universe, extraordinary high energy levels meant that only massless particles existed, which makes the concept of time irrelevant, mathematically speaking. Looking far into the future (ten to the power of 100 years), the universe will also be massless, all matter having been consumed by black holes that slowly dissipate their energy until they vanish.

Penrose claims that these two states are equivalent, so that the big bang was also the end of this universe during a different aeon, and vice versa. All of which seems to rather echo Hawking's claim that we need a change of mindset with regards to questions of the universe's origins.

Both books are intriguing in their own very different ways - just don't expect to get a satisfactory answer to life, the universe and everything any time soon.