Italy, Florence, and the Papacy

Galileo and the overthrow of Aristotle

The beginnings of modern philosophy and modern science

Galileo published his observations in Sidereus Nuncius in March, 1610:

"I should disclose and publish to the world the occasion of discovering and observing four Planets, never seen from the beginning of the world up to our own times, their positions, and the observations made during the last two months about their movements and their changes of magnitude; and I summon all astronomers to apply themselves to examine and determine their periodic times, which it has not been permitted me to achieve up to this day . . . On the 7th day of January in the present year, 1610, in the first hour of the following night, when I was viewing the constellations of the heavens through a telescope, the planet Jupiter presented itself to my view, and as I had prepared for myself a very excellent instrument, I noticed a circumstance which I had never been able to notice before, namely that three little stars, small but very bright, were near the planet; and although I believed them to belong to a number of the fixed stars, yet they made me somewhat wonder, because they seemed to be arranged exactly in a straight line, parallel to the ecliptic, and to be brighter than the rest of the stars, equal to them in magnitude . . .When on January 8th, led by some fatality, I turned again to look at the same part of the heavens, I found a very different state of things, for there were three little stars all west of Jupiter, and nearer together than on the previous night." . . ."I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury around the Sun; which was at length established as clear as daylight by numerous other subsequent observations. These observations also established that there are not only three, but four, erratic sidereal bodies performing their revolutions around Jupiter."




Chronology of the 17th century

Galileo page on Wikipedia

Galileo photos on Wikipedia

Please be sure to visit the Galileo page on Wikipedia and click on the photos. You will find photos of the villa in which Galileo spent the last years of his life under house arrest and also of the convent where his daughter Maria Celeste lived. You can click on the thumbnail photos to see the larger photos. The villa and monastery are in Arcetri, just outside Florence.


No required reading.


I highly recommend this wonderful book to you and am delighted that it is now available in a paperback edition. It is a book that will capture your heart as you read of Galileo's extraordinary daughter Suor Maria Celeste and read her touching letters to her beloved father. We will visit her monastery on our Galileo night, so it will be a great night with beautiful pictures of the hills south of Florence where Galileo and his daughter lived their lives.

Dava Sobel,

Galileo's Daughter,

Penguin Books,

ISBN 0140280553