hypothesis gained momentum when GalileoGalilei (1564-1642)
published his Dialogo in 1632. Long a convinced Copernican,
Galileo thought he had proof of the theory when he viewed four
satellites of Jupiter through his telescope and saw that they
appeared in different positions relative to the planet. Convinced
that they were circling Jupiter just as the earth was revolving
around the sun, he found himself in trouble with the Church. In
1616 Copernicanism was examined by the Qualifiers of the Holy
Office and Galileo was forbidden to teach it. However, in 1623,
his good friend, Maffeo Barberini, became Pope Urban VIII and
Galileo, who assumed that the intelligent Pope would see things
his way, asked the Pope's permission to write a book showing the
truth of the Copernican theory. Of course, the Pope refused and
Galileo restated his request, asking for permission to argue both
sides of the question, the earth-centered and the sun-centered
theories. To this the Pope agreed and Galileo produced the Dialogo
which was anything but an equal treatment of both theories. Cast
in the form of a dialogue between three characters, Salviati (named
for a friend of Galileo's and who spoke for Galileo), Sagredo
(an intelligent laymen who, while not an astronomer, could recognize
the "truth"), and finally Simplicio, whose name tells the story.
Poor simple Simplicio thought the earth was the center of the
universe! When the book was published, the Pope and his advisors
were furious, convinced that Galileo had betrayed them. The book
was recalled, and its production resulted in the trial of Galileo.
Dialogo di Galileo Galilei Linceo matematico sopraordinario
dello stvdio di Pisa. E filosofo e matematico primario del serenissimo
gr. Dvca di Toscana. Doue ne i congressi di quattro giornate si
discorre sopra i due massimi sistemi del mondo tolemaico e copernicano;
proponendo indeterminatamente le ragioni filosofiche, e naturali
tanto per l'vna, quanto per l'altra parte.
Fiorenza, Per Gio: Batista Landini, 1632.
was the first book DeGolyer purchased for the Collections when
he went to Europe in 1949. The Collections' copy of the Dialogo
belonged to Galileo himself, and includes changes and corrections
in his own handwriting for the second edition. The handwriting
was verified by Galileo expert, Stilman Drake, when he visited
the Collections in 1983. This book is one of four of the twelve
first editions of Galileo's works in the Collections that contains
his own handwriting. Neither Copernicus and Galileo questioned
the circularity of planetary orbits.