Book Review: Galileo's Telescope
/Galileo's Telescope: A European Story
Bringing the spyglass to the world stage meant shifting that world and turning it upside down. If the Moon viewed through the telescope looked as mountainous as Earth, if Jupiter had its own satellites just like Earth, if the Sun, with its spots, was as corruptible as Earth, then this made it all the more likely that Earth was a planet just like all the others and that, like Venus, it circled the Sun … If the sky was subject to generation and corruption, could it continue to be the home of angels and saints? And could Hell, inhabited by demons and the damned, be at the center of the Earth if our planet, in turn, was in the sky and no longer the region furthest from heaven?
A 1500-year-old theocratic hegemony straddling half the planet had based the tenets of its very existence on the geocentric understanding of the universe put forward by Scripture and Aristotle, and that hegemony's reaction to any challenges to its authority was swift and brutal; Galileo was in his mid-thirties when Giordano Bruno had been burned to death screaming in agony by the Church for, among other things, the crime of saying the Earth wasn't the center of the universe. And what was dangerous for Bruno was far more dangerous for Galileo, for what Bruno could only theorize, Galileo could show – thanks to his marvelous spyglass, the revolutionary device at the heart of this hugely enjoyable book, by far the most lively and challenging book on Galileo to appear in decades. That spyglass, on display in the professor's workshop during his stay in Venice, was an object of nervous-laughter caution on the part of the grandees who trekked to try it out:
Just for a moment, lets try to imagine this scene, never losing sight of Galileo. How amused he must have been to watch all those eminent Venetian aristocrats sweating and panting as, one by one, they climbed the narrow steps of the bell tower of St. Mark's and then, at the top, crowded around that odd device, kneeling in front of it and, with one eye open and other squeezed shut, “discovering sails and vessels at sea so far away that when they headed to port under full sail, it took them two hours or more before they could be seen without [his] spyglass.”
Grown men jumped a step backwards from that viewer, physically jolted by what our authors quite rightly describe as a “new way of seeing.” One battered old condottiero was only restrained from running Galileo through the belly for “some kind of damn trick” by their mutual friend Sebastiano Venier (to whom, therefore, the history of science owes an unacknowledged debt of some magnitude). Our authors do a very readably thorough job of tracing the provenance of that spyglass in the various libraries, laboratories, and glazier shops of Europe (hence their book's intentionally provocative subtitle), and they also pull in a wide cast of characters who formed Galileo's circle of intellectual colleagues and rivals. But in the end they keep coming back to this one singular device and the towering, restlessly brilliant mind behind it. “His discoveries seemed endless,” as they simply put it, and “the havoc he was wreaking could not have been more devastating.”Much of that havoc was wrought, our authors remind us, by the written word. Galileo was a master polemicist and a not-half-bad prose stylist of a rough-edged Thomas Paine kind, not afraid to pick fights and very good with a catchy phrase that sticks. In a long lifetime of trying, he never quite succeeded in smoothing the bluntness that comes naturally to people who determine truths with their own eyes and brains, and this gets him into a lot of famous trouble as Galileo's Telescope progresses through his career. But it was his Starry Messenger, the tract Sidereus nuncius of 1610 that was the central seismic event, the shot Galileo put across the bow of all human intellectual history, and our authors give it the prominence it deserves:
The images of lunar mountains and valleys, the clear outlines of the starts composing the Praesepe and the Orion Nebula and the constellation of the Pleiades, and the discovery of the four celestial bodies around the planet Jupiter, with the day-by-day depiction of their motion and exact position, made this text unique among the books of the era. It contained a different way of seeing not only the Earth but also humans and their relationship with the world and nature. In the intellectual history of the modern age, perhaps no other book circulated as quickly and widely as the Sidereus nuncius, and only maps can instantly reveal the full extent of its success. Only the publication of Charles Darwin's Origin of the Species (1859) would achieve the same international acclaim.
One might have wished our authors had seen fit to include Isaac Newton's Principia on that short shelf, but little nitpicks like that are all that can be chipped against this splendid book. Everyone who's ever looked up at the night sky and wondered should read it and re-make the acquaintance of the man who showed us all what we were really looking at.
