We tend to think of ourselves as surface dwellers, roaming about on the surface of Earth, far beneath the inhospitable emptiness of space. There are blue skies above us and life-sustaining air all around. It seems so light, this atmosphere of ours, that we hardly give it any thought. Indeed, unless it threatens us with disastrous weather, we take it largely for granted. But air is not as light and insubstantial as it seems, nor is the dangerous radioactivity of space all that far away. More than 99% of the air in our atmosphere is within only 100 Km of the surface.
As Gabrielle Walker reminds us in her new book, An Ocean of Air: Why the Wind Blows and Other Mysteries of the Atmosphere, we live, thankfully, at the very bottom of this ocean of air. In this beautiful and eminently readable book, Walker tells us the story of air and how it transformed Earth long ago to make it hospitable to larger life forms, including ourselves, but also how it continues to protect us from the dangers of space and now must be protected by us.
Gabrielle Walker is a freelance writer, broadcaster, and speaker specializing in science and technology, with particular emphasis on energy and climate change. She has been an editor at Nature and Features Editor at New Scientist, for whom she now acts as consultant. She has a doctorate in chemistry, has written, broadcast, and lectured widely on science and policy issues, and has been a visiting professor at Princeton University. Her first book was Snowball Earth, the story of Paul Hoffman's quest to prove that the Cambrian Explosion, the moment in geological time when multifarious complex life forms first emerged, resulted from a cataclysmic explosion some 700 million years ago. An Ocean of Air is her second book.
An Ocean of Air opens with the story of Captain Joseph W. Kittinger, a test pilot for the U.S. Air Force, "the man who fell to Earth and lived." Walker throws her readers right into the story of air by taking us twenty miles up into the atmosphere, a place with air so thin we couldn't possibly survive without the protection of a pressure suit. Instruction begins immediately. We observe, with Kittinger, the thin blue line that "has transformed our planet from a barren lump of rock into a world full of life… the only shield that stands between vulnerable earthlings and the deadly environment of space." As he steps off the platform of the gondola hanging beneath a giant helium balloon, we plunge with him through the layers of air at close to the speed of sound. We learn, as he falls, about solar wind channeled away from Earth by its magnetic field, lethal x-rays intercepted and absorbed by the ionosphere, dangerous ultraviolet rays soaked up and diffused by ozone, and about the troposphere, that "thick, life-giving blanket of air, wind, and weather that turns our planet into home." Sounds like an action hero story.
An Ocean of Air is a scientific book, but it certainly does not feel like it. This book is an interesting, fun, and mostly light, read. It's not just the near total absence of scientific formulas and jargon that makes the book so readable. Don't be fooled. This is not dumbed-down science. What does the trick is Walker's use of narrative, her storytelling. An Ocean of Air reads like an anthology of short, interconnected stories that just happen to have a unifying scientific theme. She tells the story of air by stringing together short biographical tales of the many natural philosophers, as scientists were formerly called, whose discoveries and life's work have shed light on the mysteries of air. These stories are like a scientific relay race in which material is added into the baton by each runner, and we, the current holders of the baton, have not only benefited from the accumulated knowledge contained therein, but continue to add to it.
As Simon Singh from The Daily Telegraph writes on the dust jacket, "[t]he scientists are almost as interesting as their science." They are indeed. After Kittinger, we learn about Galileo Galilei, the man who is said to have muttered after his famous forced recantation, "Eppur si muove!" ("And yet it moves!"), yet could not bring himself to believe that the atmosphere itself was heavy. Then there is Evangelista Torricelli, the young man who worked with Galileo in his final three months, who proved that vacuum doesn't suck, but rather that air pushes. It is from Torricelli that Walker borrows the title of her book, for he wrote that "We live submerged at the bottom of an ocean of air."
There are so many memorable characters in this book. Allowing us to get to know each person a little, to get a little glimpse of the individual, not just the scientific discovery attached to the name, makes the science easy to read. That and the fact that the language is straight-forward, though not plain, and omits much of the highly technical stuff behind the science. Most of us have likely heard of a great many of the scientists, mostly men by virtue of the times, and have learned some of the things they discovered. But knowing a little more about the people brings the stories closer and aids memory. The overall intent of the book, so it seems to me, is not to pass on minute scientific details, but rather to impress on her readers the larger picture of the wonder that is the air, as also its importance to life as we know it.
Air is the protagonist of An Ocean of Air, with the various scientists who discovered the various properties and functions of air cast as important but supporting characters. Air and the atmosphere it forms is in many ways presented as a superhero figure, a figure responsible not only for the emergence of larger life forms on this planet, but also for protecting the same life forms from the hazards of space. In some ways, to continue the dramatic metaphor, scientists play the part of the chorus that interrupts the narrative from from time to time to draw attention to or explain something important, or to warn us of impending danger. Where do we fit in, we the reader, the non-scientist? We are not merely the audience. We have been for too long. We have an important role to play. It is up to us, something made clear in the sections on climate change, to ensure that we protect the atmosphere that protects us. Even in this, Walker is not preachy. She merely tells us stories.
An Ocean of Air is a wonderful journey behind the science of air through a series of biographical narratives. This is a book for scientists and non-scientists alike. A useful book in a time when we finally are beginning to realize that we are all a part of nature, that our actions have consequences for the planet. This is a book to be read and re-read.