A Fortunate Universe
by GA Lewis and LA Barnes, Cambridge, £18.99
In theory, universes can behave in countless different ways and the odds that they will support life as we know it are vanishingly small. We only have one example of a universe at our disposal, of course, so that theory is impossible to prove. It’s good fun pondering the possibilities, though, and Geraint Lewis and Luke Barnes bring wit as well as expertise to the task.
All manner of strange scenarios are discussed: a universe in which gravity doesn’t exist, for example, or one in which everything expands so rapidly that the cohesion of matter is virtually impossible and all we end up with is “a thin soup of hydrogen and helium”.
The staggering thing is that even in a universe very similar to our own – in terms of particles, forces and governing laws – it would take only a minuscule adjustment in the cosmic maths to produce utter sterility. The universe we inhabit is incredibly “fine-tuned for life” and the book takes an even-handed approach to the question of whether this helps or hinders the concept of a Creator.
Lewis and Barnes also inform us that, while the sums can be monstrously tricky, the basic ideas behind cosmology are “shockingly, mind-bogglingly simple”. To my surprise, they almost convinced me through their lucid explanation of various headache-inducing propositions.
And even if conceptualising the cosmos remains a baffling pursuit, we can take some solace from the fact that even the experts are worryingly short on copper-bottomed facts and figures. By the most recent models, 69 per cent of the universe is dark energy but, as Lewis and Barnes admit, “we don’t know what it is”. Twenty-six per cent is dark matter but, again, “we don’t know what it is”. Five per cent is “familiar ordinary matter”, but most of it is “diffusely scattered through the universe, so we’re not quite sure where it is”.
Just six per cent of that five per cent (that’s 0.3 per cent of the whole) is in the stars, “some of which we can see”. It would appear, then, that one universe is enough to be getting on with.
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