Galileo’s Telescope: A European Story

"I’ve chosen this book because, first of all, it’s the combinatorial power of three really good Galileo scholars, who’ve thought long and hard about different aspects of Galileo’s work and his world. It’s three experts getting together and writing a book that is seamless, it doesn’t look like three different people wrote it, it’s very well integrated, it’s very accessible. What I especially like is that it’s a real time story of the history of the telescope, which we don’t often get. What they decided to do was watch it unfolding like a news episode. How is this happening? Who is generating the news? How is the story of the telescope being transformed in each and every context? It’s not a story that starts with Galileo and it’s certainly not a story that ends with Galileo. Indeed, they leave us with a coda in which you see that the telescope has now travelled, via the commercial and the Jesuit missionary networks, all the way to India and to China. The telescope travels very far, in the early 17th century. In fact, when I was reviewing the book , I commented that by the late 17th century, people were using telescopes in the exploration of Baja California. They had been shipped to New Spain. What the book gets you to do is to think about this as an object that has to travel through very concrete networks. At each stage, people respond to the fact of the telescope and to Galileo. It takes us back to a world of diplomacy and commerce. How does the telescope—through word of mouth, letters, relationships—travel through the networks that link different parts of the world? I think the original version was maybe eight to 10 times magnification. This is where Franco Giudice, who does a lot of work on the history of the instrument, comes in. They’re really good at getting you thinking about the problems of this telescope. Most of us have never used a replica of a Galilean telescope—we’ve used the kind of telescope that Kepler modifies, that changes how you view the image through a different combination of lenses. But at roughly the same magnification, cardboard replicas are kits for elementary school students. The first thing you learn is that you can’t even see the moon in its entirety through it, even with this magnification. You learn how narrow the focal point of the lens is and then you start realizing how many observations you would have to make before you could put together the description of the new things you see in the heavens that we see in Galileo’s Sidereal Messenger in 1610. You realize that he makes it look so easy when he presents his initial observations to the public, but it’s actually really hard work. To see Jupiter’s satellites—what Galileo calls the four moons of Jupiter—or the phases of Venus, is extremely difficult. That material insight into the limits of this new scientific instrument helps you understand that we have a lot of steps to go before we get to the Hubble telescope. Galileo has taken this very important first step, but he has to do a lot of hard work. “Galileo was a great communicator of science to the public. He wanted to involve society in the project of science” What they also help us understand is that critiquing Galileo is not just about resisting new ideas; this instrument doesn’t always work. The glass is made artisanally. Sometimes you get better lenses, sometimes you get worse, even when they’re crafted by Galileo. A seventeenth-century lense is artisan – it doesn’t come out the same each time. Even when he has made one, tested it, and sent it to someone else, they don’t have the benefit of all the hard work he’s done to generate observations. Everyone has to learn how to use this instrument, and they have to get a good version of it. Even then, there are still going to be questions about the implications of the ideas. Bucciantini, Camerota and Giudice do an excellent job of showing that the questions are there from the start. It’s not simply a reactive thing that happens because Galileo pushes too hard, which is the simple version of the story. There really are a lot of questions and a lot of interest, even on the part of critics. What are people in places like Milan thinking about the telescope? There we see that the archbishop of the city, Federico Borromeo, is super interested in science. He is getting everything that’s new, but he’s also an archbishop. He’s a good example of how somebody outside of Rome is thinking along similar lines to what we see within Rome, that of course shaped the story of science and religion. Absolutely. This is why the news of the telescope is so important, because it’s also news of Galileo. Who was Galileo before he invented the telescope? He was a mathematics professor in his 40s who had published virtually nothing. He’d been teaching, people knew he was smart and interesting and witty and sarcastic. They knew that he had an agile mind. But he hadn’t done anything to gain the world’s attention. And then he did. I don’t think even he expected it to be as wildly popular, successful and controversial as it turned out to be. Galileo’s Telescope also pays close attention to what other people do with news of the Dutch spyglass. It’s the story of the simultaneous discovery of new ways of thinking about how we see the heavens. The Englishman Thomas Harriot is a fascinating figure. He writes this famous account A Briefe and True Report of the New Found Land of Virginia . He’s a mathematician and many other things. Harriot is simultaneously designing his own telescope, doing observations, and then he hears about Galileo’s work. It’s not clear that Galileo ever hears about Harriot’s work, which is interesting, that the network does not go in two directions. Then Harriot makes observations that suggest he’s now looking at Galileo’s Sidereal Messenger , looking at how Galileo presents his own illustrations of what he’s seen, as well as describing them. And yet, we don’t remember Harriot unless we resuscitate him from the historical record. He can stand in for many of these figures who appear in the book, who are also simultaneously exploring the possibilities of telescopes, whether they’ve read Galileo or they’ve gotten interested on their own. Most of them have read Galileo and heard about what he’s doing."