Galileo's Daughter

Recently I assigned my 9-year old daughter a report on the life of Galileo (1564-1642). In order to better educate myself I listened to the unabridged audio tapes of the book Galileo's Daughter: A Historical Memoir of Science, Faith, and Love, by David Sobel.

What is unique about this book is that it reveals another side of Galileo through the 125 or so surviving letters written by his eldest child, his daughter Virginia (Sister Maria Celeste) who lived in the local convent of San Matteo with her sister from an early age until her own death in her early 30s in 1634. Galileo never married Virginia's mother and so she was sent to the convent because she was deemed unmarryable. Unfortunately, none of Galileo's replies survive.

Virginia's wonderfully written letters are sprinkled throughout the book and are offered as a backdrop to the fairly straightforward biography of Galileo presented in the book. In that sense it's not really about Virginia's life but rather is an illumination of Galileo's life through the eyes of the daughter he called "a woman of exquisite mind, singular goodness, and tenderly attached to me" and to whom Galileo was very much devoted.

Not having read a biography on this subject before I was interested in both aspects but was especially drawn to the peeks at daily 17th century life offered by Virginia when she speaks of medicines she concocted in the convent's apothecary to battle bubonic plague, the constant neediness of the convent, and the care of her father's estate while he was off in Rome before the inquisition and later under a form of arrest at a bishop's residence in Siena some 40 miles from Florence. Virginia apparently even copied the manuscript of the Dialogue Concerning the Two Chief Systems of the World in preparation for its printing in 1632 and helped secure important papers left at his villa when he was before the Inquisition.

I was also struck in the early parts of the book by how much Galileo's father likely influenced the observational approach that Galileo applied to astronomy (then lumped together with mathematics) through his approach to music. Sobel also definitely paints Galileo as one who tried to work within the Catholic faith and seems to support the idea that Galileo really didn't believe he had taught contrary to the Ptolemaic system and did not believe in the Copernican system. Other tidbits I've read paint a starker picture of Galileo as a man who was roudly convinced of the Copernican system early on and who knew full well what he was doing. For example, Sobel downplays the legendary comment Galileo reportedly made under his breath, "Eppur si muove" (And yet it moves), after signing his recantation before his Inquisitors.

Unfortunately, one of the questions that remains unanswered is how his daughter felt about the matter. While its clear from her letters that she revered him and felt he was a brilliant man being smeared, you don't really get a picture of what this very intelligent woman believed about such things.

One of the interesting aspects of Galileo's work that was just touched on in the book pertain to his observations of Saturn. Being committed to the doctrine of observation over authority Galileo was convinced that Saturn was a composite object made up of three bodies; a large one in the center and two smaller ones on each side. The relative weakness of his telescope did not allow for the detail needed to perceive the rings which are easily seen in the 70mm refracting starter scope I purchased for the kids. Of course, it could also be that as Stephen Jay Gould argued the conceptual world in which he operated simply didn't have space for planets with rings and so while we could have "seen" them, he could not really see them. A few years later Galileo was shocked to observe the two smaller bodies apparently disappear as the orientation of the rings came into a perpendicular relationship to the earth. This was one puzzle he never solved.

The final chapter of the book that recounts the burial and subsequent re-burial of Galileo ends with a moving connection to Virginia which I won't spoil in case some of you haven't read the book.