Stars in His Eyes

Today’s post is from guest author Margaret Clifton, science reference librarian.

Four hundred years ago, in March of 1610, a pamphlet-like little book was published in Venice. The title page, as translated from New Latin*,sums up its contents with unabashed enthusiasm:

“Revealing great, unusual, and

remarkable spectacles, opening these

to the consideration of every man,

and especially of philosophers

and astronomers;

as Observed by Galileo Galilei

Gentleman of Florence

Professor of Mathematics in the

University of Padua,

With the Aid of a  Spyglass

                    lately invented by him,… “ 

In this little book, Sidereus Nuncius — The Starry Messenger — Galileo Galilei, then a professor of mathematics, and ingenious experimenter, described how he had first learned of the so-called ‘spyglass,’ calling it a “perspiculum” and later adopting the appellation “telescopio” — “far-seeing device” in Italian. In spite of the slight exaggeration about having ‘lately invented’ the thing, Galileo did make significant modifications to the original design that enabled him to increase its magnification, teaching himself to grind and polish lenses in order to do so. With his practical, reverse-engineering sort of  mind, Galileo had figured out, not just how to replicate, but also how to improve it, and thus, with one eye turned toward the skies and one toward advancing his own career, he quickly constructed his first prototype with some eyeglass lenses fitted into a lead tube.

He continued to experiment with the design until he had twenty- and thirty-powered versions which he promptly turned to the sky, making the first detailed observations of the Moon and then later of some little ‘stars’ he spotted next to Jupiter. These discoveries, as described in eloquent detail in the Sidereus nuncius, eventually led to a cosmological paradigm shift, but not without pain and suffering on the part of its author.

The observations of the ‘stars,’ as he called them, moons really, Jupiter’s four largest of its many moons, seen by Galileo for the first time in history and described by him in this 18 page treatise, was a monumental event that rocked both the scientific and religious worlds. Galileo observed Jupiter’s moons from Jan. 7 through 15, 1610, thinking at first that they were indeed stars, but quickly deducing that, in fact, they were planetary bodies revolving around Jupiter. What this discovery proved was that the Earth was not the only celestial body around which others revolved, convincing Galileo, not just of the truth of the Copernican system (which he already believed), but that he had found the evidence that would persuade those who refused to believe in a Universe in which all the planets orbited the Sun.

In this little book, rushed to print within 6 weeks and literally assembled as he was making his last observations of Jupiter’s moons, Galileo chose to name his newly discovered moons the ‘Medician Stars,’ after Cosimo Medici II and his brothers, the royal political dynasty of the time, and from whom Galileo hoped to obtain a court position and a higher standard of living. The moons were Galileo’s discovery; he could name them whatever he wanted, but in acknowledging the Medici he calculated on improving his prospects, and was indeed rewarded with appointment as Royal Professor of Mathematics and Philosophy in Florence. However, naming ‘stars’ after secular powers only went so far; the implication that the Earth was no longer the center of the Universe violated the Church’s sacred cosmology, and, if the Venetian Medici had a little power, the Roman Catholic Church had a lot. As far as Galileo was concerned, though, he had his proof and was ready to persuade anyone who would give him a listen.

As additional astronomical discoveries made with the telescope added credence to the Copernican view that the Sun is the center of our Universe, or at least that Earth, Venus and Mercury all revolve around it, Galileo initiated his campaign against the Church, a risky proposition during the Inquisition, even if your best friend becomes Pope. And so began the “Galileo Affair.” Inevitably Galileo was forced to face the Inquisitors, and, in spite of all his best reasoning was ultimately forbidden by the Church authorities to teach or advocate Copernicanism. In 1633 he was sentenced to house arrest for the rest of his life.

Despite this he continued to work and to make further astonishing discoveries until he died in 1642. Among other things he invented the science of dynamics, thus paving the way for Newton to develop the theory of universal gravitation, thus paving the way for Einstein to develop the theory of general relativity, thus paving the way for …

Special Event:

On February 17, from 11:30 am to 12:30 pm, in Dining Room A, Madison Building, ST&B will host the first of its series of speakers for 2010, with Michelle Thaller, NASA Scientist, discussing “Galileo: 400 Years of the Telescope.” The Library of Congress owns an original copy of Sidereus nuncius and will have this item on display after the program. This item is part of the Rare Books collection and this is a rare opportunity to view it. Other titles from the General Collections will also be on display. You can view the webcast of the lecture Galileo: 400 Years of the Telescope here.

^*  From Discoveries and Opinions of Galileo, translated and edited by Stillman Drake, copyright 1957.