100 Years of a Stubborn Little Hypothesis that Grew into a Big Theory



Why is this volcano here? Plate tectonics theory gives us the reason.

Thanks to my friends and colleagues over at Google+, I am realizing that two days from now is the 100th anniversary of the official introduction of the hypothesis of continental drift by Alfred Wegener. He wasn't the first to note the apparent fit of the continents, but he is recognized for gathering the additional evidence that turned speculation into a valid scientific hypothesis. As all first-year students of geology know, his hypothesis was not treated kindly by the geological community; he could not provide a valid mechanism for the movement of the continents, for instance. But his ideas were powerful, and eventually spurred more research, and by the late 1960s, the continental drift hypothesis had been incorporated into the theory of plate tectonics, the guiding model of geology in the present day.

The story of plate tectonics tells us much about how science works in general. New information spurs new research, and the sheer weight of the new knowledge tips the scales into entire new ways of thinking about the workings of geology, astronomy, biology, physics and chemistry. Every science undergoes a revolution every now and then. Sometimes we may get the feeling that these revolutions of thought happened long ago, but as I considered this particular anniversary, I realized how current it is: my grandmother and my wife's grandfather, who are both still with us, were kids when the first English translation of Wegener's work was published in 1922. I was a toddler when the paleomagnetologists were discovering independent evidence of plate motions in the late 1950s. I was a college student in the middle 1970s, just a few years after the basic outlines of plate tectonics had emerged. My first textbook barely mentioned the concept, in chapter 27 of 27 chapters. Today, plate tectonics is introduced in chapter one.

My students are often intrigued by the idea of plate tectonics. Many of them (some of them, anyway) actually remember learning some of the basics in elementary and secondary schools. But it seems like ancient history to them, since the events took place before they were born. But there is a big difference between an apple falling on Newton's head a few centuries ago, and events that were experienced by those who are still with us. Many of the researchers who confirmed the theory are not only still living, but are still producing important data. It would have been great to study under someone like Isaac Newton, or Johannes Kepler. Although many have retired, or will be doing so soon, geology majors can still do the equivalent today: study with the pioneers who discovered one of the most important scientific theories of our day.