The Strangest Piece of News
- Galileo: Watcher of the Skies by David Wootton
Yale, 328 pp, £25.00, October 2010, ISBN 978 0 300 12536 8
- Galileo by J.L. Heilbron
Oxford, 508 pp, £20.00, October 2010, ISBN 978 0 19 958352 2
In the winter of 1609-10, Galileo Galilei made a series of astronomical observations that added to the growing list of anomalies threatening the stability of the earth-centred Ptolemaic cosmos. His weak spyglass made mountains appear on the formerly pristine moon, resolved the Milky Way into innumerable stars, multiplied the number of objects in well-charted constellations and, most spectacularly, revealed four satellites orbiting Jupiter. Galileo swiftly published the narrative of these discoveries in the Sidereus Nuncius (‘Starry Messenger’), a quarto pamphlet of 60 pages, cramming in as many days’ observations of the Jovian satellites as he could without missing the deadline imposed by the most important opportunity for intellectual exchange in early modern Europe, the Frankfurt Book Fair. The pamphlet gestured to the possibility of using the satellites as a precise celestial clock, but relied on medieval merchant time to deliver its message. A fortnight before the fair, Galileo was still unsure of the title. On 13 March 1610, he sent the first, damp copy to his Tuscan patron and potential employer, Cosimo de’ Medici. The same day, the English ambassador to Venice, Sir Henry Wotton, sent a copy to James I, describing it as ‘the strangest piece of news (as I may justly call it)’ that he would ever have received ‘from any part of the world’. Most copies were probably sent over the Alps by Tommaso Baglioni, the book’s nominal publisher, or his boss, the excommunicated polemical printer Roberto Meietti, now in hiding behind various pseudonyms, after he’d acted as semi-official propagandist for Venice against Rome in a recent interdict controversy.
The Sidereus caused consternation, forcing into direct confrontation various instrumentalist and realist cosmologies that had been circulating in the previous few decades. (The former were used for calculating planetary positions, the latter for describing the physical universe.) Thanks to David Wootton’s careful reconstruction of the writing and printing of the Sidereus (in an article in Issue 6 of Galilaeana: Journal of Galilean Studies), we now know that Galileo’s swaggering pro-Copernicanism, the least plausible of the rival models to most astronomers at the time, was, like the title, added to the book at the last minute. The observations reported in the Sidereus didn’t prove that the universe was Copernican (as Kepler would soon show), but they did prove Ptolemy and the university professors wrong.
The fixed points in Galileo’s life are firmly established: a move from Pisa to Padua in 1592, the telescopic discoveries and publication of the Sidereus Nuncius in 1609-10, the banning of Copernicus in 1616, the publication of the Dialogue Concerning the Two Chief World Systems and trial in 1632-33, after which he was placed under house arrest until his death in 1642. The problem for the biographer lies in positioning these points in relation to each other and their contexts, then drawing the line of best fit. Galileo’s life, plotted in this fashion, describes the tragic curve of a parabola, with a long preparatory rise peaking somewhere between 1610 and 1623, then, with the setbacks of hardening opposition among Dominicans and Jesuits, a rapid fall from favour. Galileo seems to have predicted such a trajectory: when he signed his name in an Album Amicorum in 1599, he added the graph of a rising and falling body.