Galileo lived out the remainder of his life in a small villa in the hilltop village of Arcetri. His daughter Virginia obtained permission to leave her convent and come to stay with him, taking care of her father as he slipped deeper into old age, but she herself fell ill after a few months, and died in the spring of 1634. This dealt a heavy blow to Galileo, and he sank into a deep depression for months afterwards.
Finally, his spirits began to rise; for while he technically remained a prisoner, forbidden to stray beyond the villa's grounds, his wardens still permitted him to teach pupils, pursue his studies, and receive visitors. Of these there were many, including two great English geniuses: the philosopher Thomas Hobbes; and the great poet John Milton, who made the pilgrimage in 1638. Galileo still enjoyed great fame; indeed, with his books spreading through Europe and his sufferings at the hands of the Church well known and pitied, he had become a kind of living martyr to scientific truth. And the old fire still burned within him: forbidden astronomical work, Galileo set to work on a new book that would sum up his experiments in physics from earlier years. Entitled Dialogues Concerning Two New Sciences, it could not be published in Italy, where the Inquisition's hand was heavy, but Galileo negotiated with foreign printers, and in 1638 published the work in Holland. Once again, Salviati, Sagredo, and Simplicio conversed and debated, but they seemed older, mellower, less confrontational–and Simplicio seemed to have learned more about mathematics. Through these characters Galileo's contributions to physics–the greatest of any scientist before Sir Isaac Newton–were voiced to an eager continent.
This work was Galileo's final masterpiece. His eyesight was diminishing, and by the time the Dialogues were published, in 1638, cataracts had robbed him of sight. The Inquisition allowed him to visit Florence the following year, where he saw a physician and heard Mass. In his final three years, he was attended by a number of young men, who read to him, and to whom he dictated his correspondence until his hearing failed as well. In constant pain from a low- grade fever, he occupied himself by playing the lute, his father's favored instrument. He died on January 8, 1642, a month shy of his seventy-eighth birthday.
Galileo was unquestionably one of the greatest minds in history. Any one of his scientific accomplishments would have earned him a place in the first rank of discoverers, and the sheer breadth of his work is almost unparalleled. His contributions to physics, from the famous experiments in downward velocity, to his articulation of the principles of the lever and pulley, to his formulation of the law of inertia, would not be matched by any scientist until Newton. In astronomy, his telescope opened the night sky to human understanding for the first time. His gaze reached to the craggy mountains of the moon, to the distant satellites of Jupiter, to the mysterious face of Venus, and to the spotted surface of the sun. He had called his first astronomical book Sidereus Nuncius, the "Starry Messenger," and indeed, it had carried a message of a new world, vast and mysterious, high above.
But it is for his confrontation with the Church, his decade-long duel with Bellarmine, Urban VIII, the Jesuits, and the Inquisition, that Galileo will always be remembered. And here we have a tragedy–the tragedy of an old man suffering for the truth–but, even more serious, the tragedy of an institution–the central institution in Europe–losing its way. In its dealings with Galileo, the Church that had long been the guardian of learning in Europe transformed itself into an enemy of knowledge, allowing the fears and pressures of a turbulent era to overcome prudence, charity, and good sense. In a sense, the Church triumphed, but it was a fleeting victory–as Galileo legendarily murmured, the earth "does move," does change its position–and soon his work and the work of subsequent scientists would prove this, both figuratively and literally.