The idea of an asteroid or comet impacting with planet Earth and causing a catastrophe for mankind has long been given a cold shoulder in scientific circles. But with the notion that the dinosaurs met their fate at the hand of a rather large space rock it does not seem so outlandish anymore. NASA has started monitoring near-earth objects, but is there really something we could do if one was heading our way? Astrophysicist and science writer Andrew May provides a delightful little primer on these questions with Cosmic Impact, injecting this oft-hyped topic with a healthy dose of realism.
At first blush, you might think this book is part of the ongoing craze of spiritual mindfulness books. But let me refrain from snarky comments. Geologist Marcia Bjornerud does indeed want to instill a sense of mindfulness about deep time, but one that is, pardon the pun, grounded in geology. In her opinion, most of us lack an awareness of durations of important chapters in our planet’s history and of rates of change of many natural processes. As a consequence, we fail to see just how rapidly we are altering our planet. In one of the first paragraphs she eloquently writes:
“Like inexperienced but overconfident drivers, we accelerate into landscapes and ecosystems with no sense of their long-established traffic patterns, and then react with surprise and indignation when we face the penalties for ignoring natural laws”.
And with that, she had me hooked.
What has plate tectonics ever done for us? Not having studied geology, I have a basic understanding of the movement of earth’s continents, but this book made me appreciate just how much of current geology it underpins. Marine geophysicist Roy Livermore, who retired from the British Antarctic Survey in 2006 after a 20-year career, convincingly shows here that the discovery and acceptance of plate tectonics was a turning point in geology, on par with Darwin’s formulation of evolution by natural selection. To paraphrase evolutionary biologist Theodosius Dobzhansky: nothing in geology makes sense except in the light of plate tectonics.
Before plate tectonics became an accepted idea in geology, Lyell’s doctrine of uniformitarianism still ruled supreme (see my review of Cataclysms: A New Geology for the Twenty-First Century for a short introduction). A corollary was that the continents supposedly had always been where they are now. One observation scholars had to explain away was that the same fossils occur on both sides of the various oceans. Looking at maps, some people noticed the thin strip of land connecting North and South America and concluded that land bridges must have formed and sunk beneath the waves at just the right times in history to enable migrations (see Four Revolutions in the Earth Sciences: From Heresy to Truth for more details). As explained in The Tectonic Plates are Moving!, we know better nowadays. Nevertheless, the concept of land bridges is still alive and well today, and palaeobotanist Alan Graham here introduces five of them, exploring their effects on biogeography, climate, and human history.
Try as we might, science is very much the work of human beings with all their foibles. As such, scientific advances aren’t always straightforward and can run into opposition within scientific circles when new ideas run counter to currently established ones. In Four Revolutions in the Earth Sciences, American geologist James Lawrence Powell demonstrates this by taking the reader through the history of four ideas in the earth sciences that initially weren’t accepted. This was a book I very much wanted to read.
Was the asteroid impact that caused the extinction of the dinosaurs a one-off? Or are other mass extinctions in earth’s deep history perhaps also linked to impacts of extraterrestrial bodies? Many scientists are reluctant to accept this idea. In Cataclysms, Rampino argues that it is high time to cast off the spirit of Lyell that continues to haunt geological thinking and embrace a new era of catastrophism.