Mark Denny's "The Science of Navigation"

Mark Denny is a theoretical physicist who worked in academia and industry. He is the author of a number of books for scholars, students, and general readers, including Gliding for Gold: The Physics of Winter Sports; Their Arrows Will Darken the Sun: The Evolution and Science of Ballistics; Super Structures: The Science of Bridges, Buildings, Dams, and Other Feats of Engineering; and the recently released The Science of Navigation: From Dead Reckoning to GPS.

He applied the “Page 99 Test” to The Science of Navigation and reported the following:

In my books I like to explain technology with a historical narrative. I aim to omit technical details while getting across key concepts in a lively manner, as different as possible from a formal lecture. Sometimes this is a difficult balancing act, made easier when the subject matter is inherently geometrical, because core ideas can then be conveyed via diagrams and figures. In such cases a picture really does replace a thousand words, and gets across an essential part of the story quickly and painlessly.

Page 99 of my navigation book happens to be about maps, and how it is that the surface of a three-dimensional globe can be projected onto a two-dimensional piece of paper with minimal distortion. It explains, mostly with a diagram, the three main families of map projections and how they work. (The well-known Mercator projection, invented in the sixteenth century, has the unique property that a mariner’s course—say north-north-east as determined by his magnetic compass—appears as a straight line on such a map. For navigators of old with crude equipment on stormy seas, this matters.)

There are four “quadrants” to this book—it seemed appropriate to use the navigators’ term for division—each with a couple of chapters: geodesy (the physical earth), cartography (maps), exploration (a convenient vehicle for sharing a few of the amazing historical expeditions), and modern navigation (electronic equipment). It’s a little humbling, and more than a little interesting, to see just how our advances in navigation techniques have been matched in every detail within the animal world, where the need to navigate is every bit as important among migratory species. So I end the book with a demonstration of each technique within the animal world. Are there really animals with a GPS system? Well, yes there are, though their system is terrestrial and does not dependent on artificial satellites…but the explanation is on p231, not p99.

Learn more about The Science of Navigation at the Johns Hopkins University Press website.

--Marshal Zeringue