The nature of a revolution: Galileo's SIDEREUS NUNCIUS as a scientific text

Exhibit by Ashray Jani

A Starry Message

Before Sidereus Nuncius (originally published in 1610), the branch of natural philosophy which we would now call astronomy, existed without naturalistic representations of celestial objects. Through his newly invented telescope (the first of its kind), Galileo observed new stars in the constellations of Orion and Pleiades, the moons of Jupiter, and the topography of our nearest neighbour, the Moon. Furthermore, Sidereus’ publication was highly influential as not only were its astronomical observations entirely unanticipated and arresting in their impact, but its rapid preparation and printing, all in just over six weeks, was a record for any significant scientific book of that period.

In his dedicatory letter (above), Galileo named the four satellites of Jupiter as the Medicean stars, a reference to the powerful Medici family, whose influence in Renaissance Italy was unmatched. Galileo was obsessed with gaining the approval of the Medici family, as a position in their court would have elevated him from a 'lowly' mathematician to a higher social status and economic class. Furthermore, a position in court might have helped to socially 'legitimize' Galileo's discoveries. Though he was successful in ingratiating himself to Cosimo II, who became Galileo's generous patron, the Grand Duke was no Copernican - the Medici rewarded Galileo's discoveries not because of their technological usefulness or scientific importance, but because they prized them as spectacles, as exotic marvels.

According to Galileo, the discovery of Jupiter’s satellites demonstrated that the motion of celestial bodies could have centres other than the Earth. Thus, Sidereus was the first public declaration of Galileo's belief in the Copernican system. In his letter dedicating their discovery to the Grand Duke of Tuscany, Cosimo II de’ Medici (for whom he named these satellites ‘the Medicean stars’), Galileo wrote that these

"four stars […] make their journeys and orbits with a marvellous speed around the star of Jupiter, the most noble of them all, with mutually different motions, like children of the same family, while meanwhile all together, in mutual harmony, complete their great revolutions every twelve years about the centre of the world, that is, about the Sun itself."

In order for Galileo to convince the reader that the Moon's surface was rough like the Earth's, he had to make the argument that the spots (shadows caused by mountains, craters, and other topographical features) changed in accordance with the angle of illumination.

Lunar Imperfections

Galileo's images of an imperfect Moon are considered especially influential in institutionalizing the Copernican principle – that the Earth does not occupy a privileged position in the universe. These were the first images to show the lunar surface as rough and cratered and its mountains and valleys represented a strikingly different conception of the Moon than Galileo's seventeenth-century audience had ever known.

An imperfect and mountainous Moon profoundly questioned orthodox thinking (established in antiquity by Aristotle and Ptolemy) that the physical nature and principles of heavenly bodies differed in character from those on Earth. The Moon was considered of a fifth element – a ‘quintessence’ or ‘ether’ – which was incorruptible and resided in a higher – and thus, superior – plane than the heavier, terrestrial elements of earth, water, fire, and air.

For them, the Earth, and thus humans, were at the centre of the universe and these perfect heavenly bodies revolved around us. Thus, geocentricity was inherently anthropocentricity, and by demonstrating that the Moon was very similar to Earth in its structure and features, Galileo undermined these misconceptions and suggested evidence for Copernicus’ ideas.

But does Sidereus deserve to be called the first scientific text? Science, as we understand it, and require it, to exist today is circumscribed by the standards we’ve come to expect of our own print culture: with its uniform editions, mass reproduction, and typographical fixity. But, could print in the early 17^th century be trusted enough for us to consider such early books successful in producing knowledge? Were Galileo’s observations reproduced with the standards of modern science in mind? No, unfortunately early print did not have the capability to reliably reproduce works, and Sidereus is a famous example of that.

A Crisis of Copyright

Galileo had no private press; thus, he could not oversee the production of his own work, particularly the illustrations. The democratization of print also birthed more dubious channels for reproducing knowledge and soon, pirated editions began appearing across Europe – one in Frankfurt in 1610, another in London in 1653, and again London in 1683, to name a few. Each time Galileo's moons were further degraded, revealing fewer of their original topographical features.

rows of pirated moons

Galileo's original copper engravings (top row) became steadily more degraded as they were reproduced as woodcuts in Frankfurt (second row), and twice in London (third and fourth rows) (Johns, Adrian. 1998. The Nature of the Book: Print and Knowledge in the Making. Chicago: The University of Chicago Press.). The Frankfurt edition inverted the order of the first two images and rotated them, setting a precedent for others printers. This became the preferred model for the reprints which spread throughout Europe for the rest of the century, and not the originals as Galileo intended.

We at the CRRS are quite lucky as in fact our own edition is an authorized reprint of Galileo's original, published in 1655 in Bologna, thus the woodcuts used in this printing are accurate reproductions of Galileo's engravings. However, this fidelity to Galileo's original was not the norm, as the above image illustrates.

two pleiades

The pirated editions also set an alternative standard for how stars are supposed to be represented – white on black (right) (Galilei, Galileo. 1610. Siderevs Nvncivs [Sidereus Nuncius]. Prostat Francof, 1610) while Galileo’s first edition (and the 1655 reprint) depicts them black on white (left).

However, despite the inverted orientation and degraded clarity of these pirated images of the Moon, the consistency between them is their rough, imperfect, and earth-like quality. For Galileo, the images of the Moon were visual aids to the text – the message was in the words, not the pictures. Sidereus was dismantling the traditional belief that there was an ontological difference between celestial bodies such as the Moon and terrestrial ones thus, for Galileo, an argument about the nature of the moon was not a ‘scientific’ undertaking but rather a philosophical one. In fact, the original engravings were themselves inaccurate reproductions of Galileo's inkwash images – he exaggerated the size of the large crater in the middle in order to illustrate his argument concerning its resemblance to large earthly valleys.

inkwash

Galileo's original watercolour sheet of inkwash images (Galileiana 48, f. 28, Biblioteca Nazionale Centrale, Florence) lack the outsize craters and dramatic shadows cast by mountains found on the published engravings

Thus, to characterize Galileo and Sidereus as leading the vanguard of the print and scientific revolutions would be a mischaracterization of the capabilities of print and the status of ‘science’ at the time. Print was not self-evidently creditable, and early modern readers and writers, well aware of the realities of piracy, couldn't be certain how the book they held had come to be. This lack of trust and authority, in addition to Galileo's disinclination for observational accuracy, meant that Sidereus' status as capital-R 'revolutionary' in print and science is questionable at best. Despite this, Sidereus was philosophically ground-breaking and literarily inventive since Galileo used the book, similarly to his telescope, as a technology to mediate knowledge which unlocked a new way of perceiving the world around us.

Primary Sources

Galilei, Galileo. 1655 [original 1610]. Sidereus Nuncius [Starry Messenger]. Bologna: Ex typographia H H. de Ducijs

Secondary Sources

Biagioli, Mario. 1999. "Galileo the Emblem Maker." Isis 230-258.

Cunningham, Andrew, and Perry Williams. 1993. "De-Centring the 'Big Picture': "The Origins of Modern Science" and the Modern Origins of Science." The British Journal for the History of Science 407-432.

Gingerich, Owen, and Albert Van Helden. 2003. "From Occhiale to Printed Page: the making of Galileo's Sidereus Nuncius." Journal for the History of Astronomy 251-267.

Giudice, Franco. 2014. "Galileo's Cosmological View from the Sidereus Nuncius to Letters on Sunspots." Galilaeana 49-63.

Johns, Adrian. 1998. The Nature of the Book: Print and Knowledge in the Making. Chicago: The University of Chicago Press.

Morar, Florin-Stefan. 2010. "Constructing Scale." Paper Worlds: Printing Knowledge in Early Modern Europe. Cambridge: Harvard University, May 21.

Shapin, Steven. 1996. The Scientific Revolution. Chicago: The University of Chicago Press.

Spiller, Elizabeth. 2000. "Reading through Galileo's Telescope: Margaret Cavendish and the Experience of Reading." Renaissance Quarterly 192-221.

Winkler, Mary, and Albert Van Helden. 1992. "Representing the Heavens: Galileo and Visual Astronomy." Isis 195-217.