solar light by reflection from the body of the earth, as he seemeth to say. So as upon the whole subject he hath first overthrown all former astronomy – for we must have a new sphere to save the appearances – and next all astrology. For the virtue of these new planets must needs vary the judicial part, and why may there not yet be more? These things I have been bold thus to discourse unto your Lordship, whereof here all corners are full. And the author runneth a fortune to be either exceeding famous or exceeding ridiculous. By the next ship your Lordship shall receive from me one of the above instruments, as it is bettered by this man.
In Prague, the highly respected Johannes Kepler, imperial astronomer to Rudolf II, read the emperor’s copy of the book and leaped to judgment – despite the lack of a good telescope that could confirm Galileo’s findings. ‘I may perhaps seem rash in accepting your claims so readily with no support of my own experience,’ Kepler wrote to Galileo. ‘But why should I not believe a most learned mathematician, whose very style attests the soundness of his judgment?’
The copy of The Starry Messenger that had the greatest impact on Galileo’s life, however, was the one he sent to Cosimo, along with his own superior telescope. The prince expressed his thanks late in the spring of 1610 by appointing Galileo ‘Chief Mathematician of the University of Pisa and Philosopher and Mathematician to the Grand Duke’. Galileo had specifically stipulated the addition of ‘Philosopher’ to his title, giving himself greater prestige, but he insisted on maintaining ‘Mathematician’ as well, for he intended to prove the importance of mathematics in natural philosophy.
In negotiating his Tuscan future, Galileo requested the same salary he had recently been promised by the University of Padua – the figure of one thousand to be paid now in Florentine scudi instead of Venetian florins. Rather than plead for more money, he made the base pay stretch further by seeking official release from responsibility for his brother’s share of their sisters’ dowries.
Galileo also secured a bonus in personal liberty by arranging for his university appointment at Pisa to entail no noisome teaching duties. He would be free to study the world around him for the rest of his days, and to publish his discoveries for the benefit of the public under the protection of the grand duke, who promised to pay for the construction of new telescopes.
[IV] To have the truth seen and recognised
NINE-YEAR-OLD LIVIA rode south with her father when he moved to Florence to assume his new court post in September of 1610. They left behind the serpentine canals of Venice, where the doge’s palace brushed the water’s edge like a fantasy spun from pink sugar and meringue. They crossed the fertile Po Valley and the Apennine spine of the Italian peninsula into the foreign country where the grand duke reigned. Italy in the seventeenth century comprised a pastiche of separate kingdoms, duchies, republics and papal states, united only by their common language, often at war with one another, and cut off from the rest of Europe by the Alps.
The landscape changed. Spires of cedar and cypress trees soared out of the rolling terrain, while ochre stucco houses sank roots into it. Here Galileo introduced Livia to the earth tones and square, sensible beauty of Tuscany. His older daughter, Virginia, already awaited them in Florence. She had gone the previous autumn at the insistence of Galileo’s mother, who took Virginia home with her after an unhappy visit to Padua. Finding her son too absorbed in his new spyglass to extend the sort of hospitality she demanded, and her not-quite daughter-in-law not worthy of her attention, Madonna Giulia cut short her intended stay and returned to Tuscany.
‘The little girl is so happy here’, she crowed in a letter to Alessandro Piersanto, a servant in Galileo’s house, ‘that she will not hear that other place mentioned any more.’
Neither Virginia nor Livia had any idea when they would ever see their brother Vincenzio again. For the time being at least, Galileo deemed it best for the boy, still a toddler, to remain in Padua with Marina.
Soon after Galileo’s departure, Marina married Giovanni Bartoluzzi, a respectable citizen closer to her own social station. Galileo not only approved of their union but also helped Bartoluzzi find employment with a wealthy Paduan friend of his. Still, Galileo continued sending money to Marina for Vincenzio’s support, and Bartoluzzi, in turn, kept Galileo supplied with lens blanks for his telescopes, procured from the renowned glassworks on the island of Murano, within the waterways of Venice, until Florence proved a source of even better clear glass.
Galileo rented a house in Florence ‘with a high terraced roof from which the whole sky is visible’, where he could make his astronomical observations and install his lens-grinding lathes. While waiting for the place to become available, he stayed several months with his mother and the two little girls in rooms he let from his sister Virginia and her husband, Benedetto Landucci. Galileo’s relatives provided an amicable enough atmosphere in their home, despite the recent legal fracas, but ‘the malignant winter air of the city’ made him miserable.
‘After the absence of so many years,’ Galileo lamented, ‘I have experienced the very thin air of Florence as a cruel enemy of my head and the rest of my body. Colds, discharges of blood, and constipation have during the last three months reduced me to such a state of weakness, depression and despondency that I have been practically confined to the house, or rather to my bed, but without the blessing of sleep or rest.’
He devoted what time his health allowed to the problem of Saturn, much further away than Jupiter – at the apparent limit of his best telescope’s resolution – where he thought he could just discern two large, immobile moons. He described what he had seen in a Latin anagram, which, when correctly unscrambled, said, ‘I observed the highest planet to be triple-bodied.’ Thus staking his claim to the new discovery without making a fool of himself before establishing proper confirmation, he dispatched the anagram to several well-known astronomers. None of them correctly decoded it, however. The great Kepler in Prague, who by this point had held the telescope and deemed it ‘more precious than any sceptre’, misinterpreted the message to mean Galileo had discovered two moons at Mars.*
All through that same autumn of 1610, with Venus visible in the evening sky, Galileo studied the planet’s changing size and shape. He kept a telescope trained on Jupiter, too, in a protracted struggle to ascertain the precise orbital periods of the four new satellites further to validate their reality. Meanwhile, other astronomers complained of struggling just to catch sight of the Jovian satellites through inferior instruments, and therefore they questioned the bodies’ very existence. Despite Kepler’s endorsement, some sniped that the moons must be optical illusions, suspiciously introduced into the sky by Galileo’s lenses.
Now that the moons had become matters of the Florentine state, this situation required immediate remedy to protect the honour of the grand duke. Galileo scrambled to build as many telescopes as he could for export to France, Spain, England, Poland, Austria, as well as for princes all around Italy. ‘In order to maintain and increase the renown of these discoveries,’ he reasoned, ‘it appears to me necessary…to have the truth seen and recognised, by means of the effect itself, by as many people as possible.’
Famous philosophers, including some of Galileo’s former colleagues at Pisa, refused to look through any telescope at the purported new contents of Aristotle’s immutable cosmos. Galileo deflected their slurs with humour: learning of the death of one such opponent in December 1610, he wished aloud that the professor, having ignored the Medicean stars during his time on Earth, might now encounter them en route to Heaven.
To cement the primacy of his claims, Galileo thought it politic to visit Rome and publicise his discoveries around the Eternal City. He had travelled there once before, in 1587, to discuss geometry with the
