A MOST IMPROBABLE JOURNEY

Count yourself lucky that you live on a planet with gravity—and silicon.

Well-known in paleontological circles for his description of the Chicxulub impact crater, which he explored in the bestselling T. rex and the Crater of Doom (1997), Alvarez (Geology/Univ. of California; The Mountains of Saint Francis: Discovering the Geologic Events that Shaped Our Earth, 2009, etc.) is at ease writing about geology, never an easy subject to treat with much grace. Here he adds a wrinkle: a garden variety geologist, he writes, will be interested in a particular mountain range, while a geologist “guided by Big History might want to understand the whole sweep of continental motions throughout all of Earth history that has given rise to all the mountain ranges.” The inclusion of environmental history in human history at a very deep scale of time has proven fruitful and has yielded good books by, among others, Richard Fortey and Colin Tudge. However, there’s a bit of a buzzword quality to the whole “Big History” enterprise, and at times it seems as if Alvarez has adopted it as a slogan in this glancing survey: “We usually take our wonderful Earth for granted…[b]ut a Big History sense of its distant past can only leave us amazed and grateful that such a violent and chancy history has given us this perfect place to live.” Granted, the human presence on the Earth is the tiniest fraction of a fraction of planetary time, and the fact that grains of sand are oriented in a certain direction in the Rockies has only a peripheral—though interesting—bearing on how engineers blasted a railroad path through the mountains 150 years ago. A little of the gee-whiz stuff goes a long way, as when Alvarez notes that “contingency is everywhere in human history”—meaning, in other words, that you couldn’t have planned it if you tried.

The science is impeccable, the history a tad simplistic. An Ascent of Man–like approach to the subject of Big History would be most welcome, but this isn’t quite it.