We come trailing not Wordsworth's clouds of glory but clouds of primal hydrogen and remnants of a galactic nebula, a fabric of cold stardust and droplets of water more than 4bn years old. We arrive with billions of years of accumulated baggage: with, for instance, an internal waste disposal system first developed in a jawless fish more than 500m years ago; and a body clock determined by the planet's spin as it orbits the sun. Spring fades into summer not because that is the natural order of things, but because the same cosmic collision that chipped off the moon and made it our companion also tilted the coalescing planet off its axis of spin by 23.5 degrees, shifting any fixed spot on Earth towards or away from the sun in its annual orbit.
The Universe Within: A Scientific Adventure
by Neil Shubin
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We see red, and marvel at the rainbow, because 40m years ago – in a suddenly cooler, more demanding world – a genetic mutation delivered in some mammalian ancestors the ability to distinguish colours, and with colour, the presence of more nutritious foods and fruits. At every scale, we are creatures of the universe we find ourselves in, the incidental product of a whole series of cosmic accidents that opened the way for us as arbitrarily as it ended the apparently inexorable careers of the trilobites or the dinosaurs, and the whole story is recorded, sometimes enigmatically, in our bodies and the landscape around us.
Neil Shubin laid out a focused version of this thesis in 2008, in his splendid book Your Inner Fish. A palaeontologist who discovered the first fossil of Tiktaalik, a perambulating fish, a creature that 375m years ago dragged itself on to land, Shubin used his find as a marvellous demonstration of the subtleties of evolution through natural selection, that preserved and redeployed the fishy inheritance to form skin rather than scales, lungs rather than gills, and hands and feet rather than fins.
The Universe Within is more ambitious: he wants to use the testimony of living things now to tell a story of everything that ever was, starting with the first trillionth of a second of creation, the making of hydrogen, helium and lithium, the arrival of gravity, the gathering of the galaxies, the forging of 89 new elements, and the supernova scattering of fabric that will eventually become stars, planetary systems, oceans, continents and people.
This should surprise no one. We evolved, so we evolved from the materials available. Even if we were created, we were fashioned – it quite bluntly says so in the Book of Genesis – from common clay: dust we were, and to dust we return. That said, this is a daring book: much of the evidence is still debated and some of it may never be unearthed. Physics has compiled a convincing history of the universe, except for the first second or so. But we cannot explain why the universe is as it is or even why it happened at all. Biology and palaeontology have outlined a convincing chronicle of life's development and colonisation, but the opening chapters are obscure and the beginning a mystery. Primate evolution is an exciting story with missing chapters, but we have no real idea why one species can ask abstract questions, compose poems and write books about the history of the universe.
But even though the direct connections between the wider cosmos and the details of physiology are sometimes difficult to make, this book offers a new, fresh way of telling the story of life, the universe and everything. There are delights in every chapter. At the beginning of the 20th century the exasperated director of the Harvard College Observatory told his staff that he could hire his maid to do their work at half the cost. He liked his threat so much that he actually employed the maid, Williamina Fleming, to examine pictures of the heavens, and catalogue and codify the stars and nebulae. Fleming was joined by other women: the group became known as the Harvard Computers (a reminder that the word is much older than the mainframe) and one of the women, Henrietta Leavitt, in 1912 spotted the link between luminosity and periodicity in a class of stars called the Cepheid Variables.
These became astronomy's first reliable long-range yardstick, with which astronomers could calculate the distances to the furthest stars. These distances turned out to be breathtaking. The same discovery led to the realisation, a few years later, that the Andromeda Nebula wasn't a nebula at all, it was another, faraway galaxy: the Milky Way was just one of what would turn out to be billions of galaxies, receding from each other at ever increasing speed.
As Shubin points out, every astronomer is a palaeontologist of sorts: the light from a distant star is direct evidence of conditions billions of years in the past. Stargazing had become a way of exploring our own ultimate beginnings. Henrietta Leavitt was employed at 30 cents an hour. There could hardly have been a richer return.
Some of Shubin's most enjoyable stories come from Harvard: another concerns the zoologist who cheerfully hurled a whole bucketful of live frogs one at a time from a five storey-building, to see whether they could survive the impact (they did). This experiment – which would not get past any modern ethics committee – is a reminder that size matters in biology: being small helps in some ways, and being big in others. It helps explain why species can migrate, can find new niches, can survive or fail to survive cataclysms. There's solid thinking on the revelation of the impact of cataclysm, and of continental drift and its role in the precipitation of the ice ages; on the discovery of the strange properties of light; on the exploration of the solar system, and on the odd, almost forgotten adventures of science.
One of these was the construction, during the cold war, of Camp Century, part of Project Iceworm: a nuclear-powered city deep in the glaciers of northern Greenland. Alas, glaciers flow, the tunnels were crushed and the camp was abandoned. But the excavation delivered the first cores of ancient Greenland ice, and these preserved a subtle record of seasonal, annual and decadal climate changes first used to trace the story of the last few million years.
The Universe Within may not quite deliver on the promise of its opening pages, but digressions such as these illuminate the story of discovery in unexpected and hugely enjoyable ways. Best of all, they hint at more to discover, and more to be told. The adventure is not over yet.
• Tim Radford's The Address Book is published by Fourth Estate.
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