Illustrations

Very rarely in the history of science has such a slender work made such a revolutionary impact. Never, perhaps, has that impact been felt simultaneously by such a broad range of non-specialist as well as specialist readers.  As shown here, the Sidereus nuncius -- including its title page and famous dedicatory epistle -- is a booklet of only 60 pages. Over half of these pages contain images of some kind, and these images are partly responsible for the immediate inteligibility and broad impact of the work.

"Although the Sidereus was addressed to philosophers and mathematicians, as specified on the title page, the radical changes it portended were universal in scope, and this is precisely why it would also be read by people outside these fields. It was a book for everyone that had nothing in common with the philosophy and astronomy books of the day. One did not even need to know Latin to understand it, as paradoxically, it didn’t matter if one actually read it or not. One merely had to leaf through it and look at the five plates illustrating the Moon, the four of the Milky Way, and the “little sketches” of the Jovian satellites, arranged chronologically, to realize that this little book was nothing like the others describing the heavens and measuring the distances between the planets. It was the images that made it uncommon, and the secret lay not in the written text, nor in the astronomy books of the past, but outside the realm of words and in the existence of a new instrument. The infinite distance separating this book from all the previous works de coelo ['on the heavens'] lay precisely in the predominance of images over text. This is what made it so innovative and original: words accompanied images, rather than the other way around."

To a significant extent, therefore, the medium of the Sidereus nuncius was the message. The new discoveries announced in this book were not primarily the product of complex mathematical calculation, abstract philosophical reasoning, or erudite philological scholarship: they resulted from a series of unprecedented empirical observations which exploded the philosophical assumptions underlying the traditional world view. By reproducing the essence of those observation on paper, the images communicated the core of Galileo's argument almost without the mediation of his brief and simple text. 

Credits 

Images: this full sequence of page-images of the Sidereus Nuncius can be explored at archive-org (select thumbnail view). 

Quotation: Massimo Bucciantini, Michele Camerota and Franco Giudice, Galileo’s Telescope: A European Story, Translated by Catherine Bolton (Cambridge, MA, 2015), p. 83.

Text: Howard Hotson (December 2018)