I love non-fiction books that give a new perspective on the things that surround us and that we often don’t think much of at all. In this case, I don’t think I will ever see air the same way again. In fact, if it had been up to me I would have titled it “The Sky Above Us” because it had a similar impact on how I saw the atmosphere as “The Sea Around Us” had on how I saw the ocean.

The book compares our atmosphere to an ocean, and based on scale alone (which I had never really thought of) the comparison is apt – Earth’s atmosphere weighs 3,750,000,000,000,000 tons. And like the oceans, its activity is an immense driver of climate patterns and the life they support; for one thing, the wind patterns in the troposphere are the reason the world’s major deserts are located 30 degrees north and thirty degrees south of the equator (examples include Sahara and the Gobi Deserts in the northern hemisphere and the Atacama and the Australian outback in the southern hemisphere), even though the equator is hotter. And yet, “we give our own overlying air-ocean so little respect that we even describe anything that’s full of air as being “empty.” (page 5).

And then there is the difference between looking up at the sky versus looking down at the sky. Almost everyone has looked up, and seen the vast expanse of blue, looking surprisingly solid and perhaps populated with some fluffy or wispy clouds. But only a few people have journeyed to the edge of space, and have seen something radically different:

“Where Earth’s surface curved away from the horizon, a glowing blue halo stood out against the blackness of space. This glow was the atmosphere, the single greatest gift our planet possesses…That thin blue line has transformed our planet from a barren lump of rock into a world full of life. And it is the only shield that stands between vulnerable earthlings and the deadly environment of space.”

Astronauts have often described it as one of the things that makes Earth look not only incredibly beautiful but also incredibly fragile.

This book is worth it for the prologue alone, which describes how Joe Kittinger used a helium-filled balloon to ascend over twenty miles above Earth, and then jumped (in appropriate survival gear). He was the first to do it; two similar jumps by others followed, the most recent in 2012. The prologue vividly described his descent through the various layers of the atmosphere that he fell through, explained some of the activity further above him (he did not ascend very far into the ionosphere because it is crackling with electrical activity), and effectively set the stage for the rest of the book. One passage I particularly enjoyed was:

“Kittinger was tumbling through another of our world's vital protective shields – the ozone layer. Ozone is miraculous stuff…High aloft it is both vigilant and resilient. Any invisible UV rays that had slipped through the ionosphere were being soaked up by a diffuse cloud of invisible gas. Split asunder by ultraviolet rays, the ozone molecules around Kittinger were calmly reforming. Like the burning bush encountered by Moses, they are constantly ablaze but never consumed.”

A subsequent chapter elaborated on the ozone layer and what it does for us, and I gained a new appreciation for it:

“Our ozone layer protects us so comfortably and effectively that we could easily never know the dangers that lie just a few miles above us. It works like a minefield: Whenever an ozone molecule is touched by an ultraviolet ray, it explodes, firing off one of its three oxygen atoms. But this is a minefield that reforms itself constantly. The shrapnel from the explosion – a stray oxygen atom and an ordinary oxygen molecule – recombine. And when they do the ozone is born again.” (page 131).

Also, this may be the first time I have heard ozone described as “beautiful” (it is a striking shade of blue). I will add that I was in grade school when the hole in the ozone layer exploded into the national conscience and CFCs became a household term. Needless to say, a great deal went over my head at the time, so it was good to have this description to fill in the gaps. A discussion of how CFCs came to be was very interesting – they were originally developed by a company conscientiously attempting to improve the safety of the refrigerators it produced in an age before government prodding. Because the book was published in 2007, I will add that a 2016 study published in Nature showed that the 1993 global ban on CFCs has been effective and the hole in the ozone layer has gradually begun to shrink and the layer itself is already slightly thicker.

Humans are not the only ones to have dramatically affected the composition of the atmosphere – plants have had – and continue to have – a huge impact when it comes to carbon dioxide: “The scale of this activity [plant-based photosynthesis] is staggering. Every year, green plants convert carbon dioxide into 100,000 million tons of plant material. To do this, plants use up 300 trillion calories of energy from the sun, which is thirty times the energy consumption of all the machines on Earth.” (page 68). The prologue also helped provide a new perspective on plant life. Kittinger landed in the desert of New Mexico, surrounded by yuccas and sagebrush. But where other people saw a dry desert and small, scrubby, and generally unattractive plants, he saw an almost impossibly lush landscape, explaining that, “fifteen minutes before I’d been on the edge of space, and now, to me, I was in the Garden of Eden.”

The book also touched on Earth’s magnetic field, which helps protect our atmosphere from the sun. Although it was not presented this way in the book, I found it helpful to think of the sun as a giant continuously detonating thermonuclear bomb throwing out just about every form of radiation on the spectrum. This radiation includes the solar wind, a stream of high-energy charged particles travelling over a million miles per hour. Earth’s intrinsic magnetic field extends over ten thousand miles into space and forces the solar wind and other blasts of electromagnetic radiation to part around it. Anything that does manage to get past the magnetic field still has the exosphere, ionosphere, and ozone layer to contend with. The result?

“I can scarcely believe that air too thin for me to breathe is yet strong enough to fend off everything that space can throw at us.

Yet it is. In October 2003, a series of explosions rocked the outer surface of the sun. A massive flare flash-fried Earth with X-rays equivalent to five thousand suns. A slingshot of plasma barreled toward us at two million miles an hour. The radioactivity it contained was the equivalent…of taking every nuclear warhead that has ever been made – not exploded, mark you, but made – and detonating them all at once.

And yet nobody on Earth felt a thing…The most massive solar flare since records began and one of the biggest radioactive maelstroms in history together met a far more formidable foe. They each arrived, and then, one by one they simply bounced off…thin air.” (page 235).

Highly recommended. ( )

A nice overview of the history of the science of the atmosphere. The book is well-written, and covers the personalities and the discoveries well, and mostly links them together pretty well. Not very technical, but gets across the physical and chemical concepts pretty well. ( )

Era il 1960 quando Joseph Kittinger, capitano dell'aeronautica, si lanciò da 32.000 metri in caduta libera e sopravvisse. Questo ed altri misteri dell'atmosfera sono ricostruiti per dimostrare che l'uomo vive solo grazie all'aria.

http://www.book-blog.com/2007/09/walker-gabriell.html ( )