Galileo Galilei in a 1636 portrait by Justus Sustermans.
Today, February 15th, is a special day. It is the birthday of Galileo Galilei, who was born in Pisa on that day in 1564. Among his many achievements were his careful observations of the Earth’s moon, the identification of four of Jupiter’s moons, and the discovery that Venus, when observed through a telescope, has phases, just like that of our own moon. The only reasonable explanation of this was that Venus orbited the Sun, and not the Earth. And just like that, the geocentric model of the universe in which everything revolved around the Earth, came to a grinding halt.
Galileo’s Jewish Connection
Galileo taught astronomy to anyone who would listen, including Jews, and his most important Jewish student was Joseph Solomon Delmedigo who was born in Candia on the Island of Crete in 1591. At the age of fifteen Delmedigo left for Italy, where he enrolled in the University of Padua. For seven years there he studied astronomy, mathematics, natural science and medicine, and was taught by none other than Galileo Galilei, who was soon to become famous for both his observations of the planets and his clash with the Church.
When Delmedigo graduated he traveled to Lublin, Vilna, and Livona, where he spent much of his time working as a physician. He ultimately settled in Amsterdam where he published his Sefer Elim, a long book (it runs over four hundred pages) that deals with philosophy, science, mathematics, and astronomy.
“Galileo my Teacher” from Delmedigo, Sefer Elim, Amsterdam 1629. 148.
In this book book Delmedigo outlined the reasons he accepted the Copernican model of the universe. In addition to explaining all of the theoretical support for the heliocentric model, he cited experimental evidence. If the planets revolved about the Sun and were illuminated by it, the amount of light that they reflect would depend on their location and distance from the Earth. And this is precisely what Delmedigo and his famous teacher had observed through the telescope.
My teacher Galileo observed Mars when it lay close to the Earth. At this time its light was much brighter than that of Jupiter, even though Mars is much smaller. Indeed it appeared too bright to view through the telescope. I requested to look through the telescope, and Mars appeared to me to be elongated rather than round. (This is a result of its clarity and the movement of its rays of light.) In contrast, I found Jupiter to be round and Saturn to be egg-shaped.
This glorious passage reminds us that religiously observant Jews were sometimes at the very cutting edge of the new astronomy. How many could claim to have been instructed by the great Galileo himself?
But don’t get carried away
The historian Andre Neher (d. 1988) viewed Joseph Delmedigo as a fearless trailblazer whose goal was not only to influence his own community, but also the Catholic Church itself. In a paper published in 1977 he wrote:
When Delmedigo published Elim in 1629, he used the term “Rabbi” in speaking of his teacher Galileo. Rabbi Galileo! Was this not something of a challenge directed to the inquisitors in Rome who were then preoccupied with Galileo and who were not to let him go until his death in 1642? Free Galileo, Delmedigo seems to be saying, or release him to us; in the midst of our Jewish community, he will not be subjected to any trial, we shall not require him to make any retraction, we shall welcome him and honor him like a Rabbi in Israel!
Well, not quite. As I have written elsewhere, this account is linguistically, historically, and conjecturally incorrect. In the first place, although the term used by Delmedigo to describe Galileo was indeed the word rebbi, in this context, it means “my teacher,” and not “my rabbi.” By translating it in this way Neher was able to support his claim that the Jews were open, receptive, and respectful to new ideas emerging in astronomy; but the linguistic reality (and much else besides) does not bear this out.
Secondly, in the years prior to the publication of Sefer Elim in 1629, Galileo had not become the “preoccupation” of the Inquisition. The work that led to the trial by the Inquisition, Dialogue Concerning the Two Chief Systems of the World, was not published until 1632. And so Neher’s claim that Delmedigo was writing a message to release Galileo is chronologically incorrect. Finally, the notion that the Jewish community would not punish one of their own for expressing antinomian views is inaccurate. It was, after all, in Amsterdam itself, the city in which Delmedigo’s books were published, that the Jewish community excommunicated Spinoza in 1656 on account of “the horrible heresies which he practiced and taught.” So I don’t think that Neher’s assessment of Delmedigo as challenging the Inquisition on behalf of Galileo was accurate. But he was certainly correct in noting the important role that Galileo must surely have played in the education of the young Jew Joseph Delmedigo from Crete, who grew up and became the first Jewish Copernican.
A selection from the Talmudology Library Galileo Collection
