Galileo’s Dream — 400 Years Later


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Four hundred years ago, a stranger from northern Europe told Galileo Galilei about the idea of the telescope. In a matter of days, Galileo had figured out the basic principles of such a device by testing lenses in pairs until he got a magnified image of objects at a distance. After that, he requested a meeting with the Venetian senate, his employers; he was a professor of mathematics at the university in Padua, part of the Venetian republic. With the meeting scheduled for August 25, 1609, he worked day and night on a series of ever-stronger telescopes, improving their magnification to a power of nine–at which point he could, from the observation deck of the campanile in San Marco plaza, demonstrate to the Doge and senators that fleets could be observed out on the Adriatic two hours before they could be seen by the naked eye. That demonstration led to big changes in Galileo’s personal life while also helping to begin a stupendous transformation of human existence by way of further applications of science and technology.
Through the fall of 1609, Galileo continued to work on improving the power of his telescopes. By January of 1610, the strongest were about thirty-two powers of magnification. From October on, he used them to look at the moon and the night skies. He had already seen that the moon was a mountainous place, and he used the Greeks’ estimate of the diameter of the moon, and simple Euclidean geometry, to calculate that the moon’s mountains must be about four miles high. He also saw a cloud of stars around the visible seven of the Pleiades, and observed the granulation of the Milky Way.
Then on January 7, 1610, he spotted three bright stars bracketing Jupiter in the plane of the ecliptic. The next night he looked again, but there were only two, and at different distances from Jupiter. The next night there were three again, but relocated; the following night was cloudy. On January 11, he saw four of them, in yet new positions–and the idea came to him that he was seeing four moons orbiting Jupiter in the way that our moon orbits Earth.
What a mind-boggling discovery!

It was also immediately suggestive concerning the nature of the solar system. The traditional view, as put forth by Ptolemy, was that the sun, the moon, and everything else in the sky orbited the Earth, which was fixed and stationary. But Copernicus had the radical idea that the rotating Earth and the other planets went around the sun–a theory that was well known among natural philosophers of Galileo’s time. Kepler was advocating it, and Galileo himself had taught the theory in his astronomy classes–though without making much of a judgment one way or the other; he taught Ptolemy too. But now he had some new evidence. If moons were orbiting Jupiter, then the basic idea that everything orbited the Earth was wrong. There were bigger systems involved.
Better yet, there were questions this brought up that could be checked with the telescope. Things that had to follow if Copernicanism was right could be tested for. Thus the basic act of science–of making a hypothesis and then looking to see whether it is confirmed or not by investigation–could be put into play. In this case, if Copernicus was right, then Venus too orbited the sun, like all the other planets, but in an orbit inside Earth’s, closer to the sun. This would explain why it was always close to the sun and only visible before sunrise and after sunset. More significant for the telescope, at certain times in the two planets’ orbits, Venus should appear from Earth as the crescent moon does, with part of its disk sunlit, and part in shadow.
When this occurred to Galileo, Venus was not visible at all, and in the rush of other investigations, it seems like he almost forgot to test this theory. But then one of his students, Castelli, reminded him of the idea when Venus became visible again, in the spring of 1610. Galileo looked, and there it was in the glass, plain to his sight: a crescent Venus!
Galileo therefore became a Copernican, which meant he was about to get into big, big trouble with officials of the Catholic Church, who felt they had the final word when it came to cosmology. Given Galileo’s brash and confrontational nature, a mighty collision of ideas and political power was inevitable.
That stranger had certainly changed his life!
At some point around 2004, I decided I wanted to tell this story, which–without too much exaggeration–could be called the story of the birth of science. I am a science fiction writer; I write novels about science. The story of the birth of science seemed a natural to me.
I had described a birth of science before, but it wasn’t ours. In my novel
The Years of Rice and Salt, almost every European died in the Black Death, but world history went on without them. And at some point–later than in our history, but not too much later–mathematicians and philosophers and artisans in Samarkand made use of a synergy of ideas from India and China and the Muslim world to begin science in a slightly different way. Being the same physical world, however, they eventually found that the same physical laws applied.
Thinking about that was a really interesting exercise in alternative history, and I did a lot of research on our own scientific revolution to help me make up my own. In that research, Galileo’s story leaped out with great clarity and drama. His personal contribution to the invention of the scientific method was astonishing to me. Repeating experiments, measuring and timing things, altering independent variables, trying to find mathematical formulas that would describe the simplified, regulated, and quantified actions he was performing; it was all there, the scientific method, in a way it had never been before. It was a truly impressive achievement–like something out of 1930s American science fiction, if you think about it. Like one of those stories in which a single bright if eccentric inventor changes the world by his own thoughts and actions.
One day an image came to me: Galileo falling up through his telescope to Jupiter’s moons, where people greeted him. It was a mysterious image, one that got its hooks into me and wouldn’t let go.
So I told Galileo’s story as a science fiction story. I sent him on a wild ride, as you will see if you read my novel. But with all that, I didn’t want to change anything that really happened to him historically; that real story has its own integrity, and an important place in world history–and it is a great story to boot. But what if there was a back story as well, previously unknown? What if he had a vivid dream life, say, or was being visited by people from another time and place?
In any case, I have now told his story. That was a joy. We know so much more about him than we do about most of the people of his time–even famous people. Consider how little we know about his contemporary William Shakespeare, for instance. But with Galileo, we have his books, which speak directly of his life and character. We also have lots of his letters, and his correspondents’ letters to him, including his daughter’s. All are very revealing. Even more unusual in terms of documentation, his trial by the Inquisition for heresy was transcribed by a nun using short-hand, so there is a record of the trial that reads like something transcribed from a tape recorder. Historically, this is extremely rare, and I wanted to take full advantage of it. Galileo’s trial was long, intense, and filled with reversals–with evidence of backstage deals and strange anomalies. It makes a gripping story in its own right, and it is such a convoluted and inexplicable sequence of events, despite the transcriptions, that it almost looks like the subject of a time war, twisted this way and that by a bitter ongoing struggle.
But that was good. The truth is, people have been fighting over Galileo’s trial from the time it happened until now; and the fighting will continue. So in a way, the image of a time war is quite apt. For my part, it was great fun to try to fit all the strange events of Galileo’s life and trial into a fictional explanation that would make sense of them. Who was that stranger who told him about the telescope, and thus changed his life and all human history? What really happened at Galileo’s trial? Galileo’s Dream offers one possible answer. I hope you enjoy it.

Kim Stanley Robinson is a winner of the Hugo, Nebula and Locus Awards. He is the author of nineteen previous books, including the bestselling Mars trilogy and the critically acclaimed Forty Signs of Rain, Fifty Degrees Below, Sixty Days and Counting, The Years of Rice and Salt, and Antarctica. He was named a Time magazine’s “Hero of the Environment” in 2008 and recently joined in the Sequoia Parks Foundation’s Artists in the Back Country program. He lives in Davis, California.
His newest novel, Galileo’s Dream, is on-sale now.