Science books – I am fond of pointing this out – are the ultimate in non-fiction, the latest if not the last word, each an exploration of those ideas that are still standing after a remorseless kicking from the community that spawned them.
Earth science books occupy a special place on the shelf of tested reality. They might be described as the ground truth; the down-to-earth, the practical, the lived-in version of science. Popular cosmology spins wonderful stories of a long time ago in a galaxy far, far away. Palaeoanthropology evokes episodes in the great human journey around the world with barely a leg to stand on (in the case of Boxgrove man 500,000 years ago, just a shin).
But earth science books really are different. We can go out and see for ourselves, we can ask the same questions and learn how to test the answers. We may be misled by the stories graven in stone, but the rocks themselves don't lie: their testimony is enigmatic, but you can interrogate them again and again. One of the riches of Richard Fortey's book is the awareness that so many wonderfully observant people before him have looked at the same evidence, and reached a very different verdict.
"History envelops the past in uncertainty, like the mist obscuring the beech trees in the valley below me. The deeper the history, the more the outlines blur, the more inferences about the past are subject to change," he writes, contemplating the view of the Alps from the Jura mountains in Switzerland. "We have a vision for our time but we can be certain it will not be the last."
The Earth is not just about how our planet's surface was made – about why things are as they are in the mountains, deserts, atolls, volcanoes and floodplains – but about how we came to see things as they are: what we once thought and why we changed our minds.
This book is a more than usually personal choice for the Guardian Science Book Club. We kicked off in March 2009 with Fortey's Life: An Unauthorised Biography. Forty or so reviews later, it seemed time to pay this author a second visit.
On the back of the paperback edition of The Earth is an enthusiastic quotation from a nameless Guardian reviewer: me, as it happens. Sometimes one can love a book, read it greedily, recommend it wholeheartedly and then, a few years later, pick it up again and find nothing much there at all. The first response wasn't an illusion: the second response was a recognition that the book had already given up its secrets, told you something you could digest and absorb, and that was that: a good meal but you can't enjoy it twice.
This book is different. It seems to me richer on the second read, with more to tell me, and with more that provokes thought. But there is another and more immediate reason for choosing it for public examination, and for public discussion at a literary festival in Cambridge this weekend. That is because we have a golden anniversary moment. The way we now think about the crust of the planet on which we depend for everything was informed by the publication of one particular research paper 50 years ago (and that came from Cambridge).
The paper, says Fortey, is referred to "in the trade as 'Vine and Matthews', and is one of those rare classics that provides a benchmark in the progress of science, like the determination of the speed of light or Planck's Constant," says Fortey. Fred Vine and Drummond Matthews published their paper in Nature, proposing that if new ocean floor formed at mid-ocean ridges, and disappeared in subduction zones at continental margins, then there would be a sure, unequivocal way of testing this, by "reading" the ocean floor for a record of periodic magnetic reversals, preserved for ever in the iron-rich basalt, symmetrically on either side of the ridge.
Before this proposal, people could happily argue that the mountains existed because the Earth was shrinking and wrinkling as it cooled or (one or two seriously proposed this) that it was expanding because of the heat generated within by radioactive decay. Afterwards, they could not. This was not, Fortey points out "one of those 'Eureka' discoveries, where prediction met result in happy consummation."
It took three years or more, some very costly voyages and some very sensitive new technology to clinch the argument, and a little longer to establish the logic of plate tectonics, and really begin to change the textbooks, the world view and the human perception of everything about us. "It was nothing less than a unifying history of the world."
I have quoted from just two chapters in Fortey's circumnavigation of the globe and his journey through time. This book really does cover the ground: he visits, or revisits, Pompeii and Naples, the Hawaiian archipelago, the Alps, the deserts of Oman, the fjords of Norway and other realms of ice and fire. He goes underground at Jáchymov, or Joachimsthal, the little Bohemian town that gave its name to the silver thaler, or dollar; and deeper too, in the metaphorical sense, to explore the mantle and core of the Earth.
And he does it with words and cadences that carry an echo of the great works of the 17th and 18th centuries (and he does list Swift as a literary hero).
If there are clichés, I missed them. He bobs across the rocks of Newfoundland "like a restless seagull". The rebound of isostasy is like "a depressed rubber duck bouncing back upwards in a bath". Little pods of ocean floor that survive in the Norwegian nappes must have been "like apple pits squeezed out from a cider mill".
So, a great story – the story that matters most to all of us, because Earth is the only place with life on it, and the history of the planet itself is a long prelude to our own short story – told in terrific language, and in a book you could read again and again; romantic, and of course all true, as far as anybody can tell right now. I still think the world of it.
On Sunday Tim Radford and Richard Fortey will discuss this book – and science writing – at Wordfest, the Cambridge literary festival
• Our next Science Book Club choice is The Physics of Star Trek by Lawrence Krauss, which Tim will review on Friday 14 June
