Galileo's Daughter is a book by Dava Sobel. It is based on the surviving letters of Galileo Galilei's daughter, the nun Suor Maria Celeste and explores the relationship between Galileo and his daughter.
Maria Celeste and Galileo maintained contact throughout her life by writing letters. Although none of Galileo's letters survived, 120 of Maria Celeste's exist. These letters, written from 1623 to 1634, depict a woman with incredible brilliance, industry, sensibility and a deep love for her father. Maria Celeste died of dysentery on April 2, 1634.
Additionally, the book chronicles some of Galileo's scientific work. Galileo's astronomical discoveries led him to adopt the Copernican system, in which the sun is the centre of the solar system with all the planets orbiting it. However, according to the Biblical interpretation at that time, the Earth was the centre of the universe and was stationary. When Galileo wished to publish a book which argued for the Copernican system, he attained the required stamp of approval from the religious authority (a requirement for all books published in Italy at the time) but circumstances led Pope Urban VIII to ban it and denounce Galileo as a heretic, even though he was a devout Catholic. Unauthorized copies of the book, however, found their way to prominent scholars outside of Italy and it was published in countries that were not under the Pope's rule, such as Germany and Denmark.
Besides being a biography of Galileo and his daughter, the book describes Galileo's scientific work. In addition to Galileo's well-known enhancements and use of the telescope and his conviction of the correctness of the Copernican system, he had many other scientific achievements. He discovered and investigated sunspots, which again did not bring him much favour with the Church, which held the Aristotelian beliefs of the heavens containing only perfect unchanging celestial spheres. He improved the compass and developed a rudimentary thermometer. He devoted the last 10 years of his life to the study of bodies in motion, laying the groundwork for Isaac Newton's laws of motion formalized in the next decades. Perhaps his greatest achievement was his promulgation of experimental science, the cornerstone of the scientific method, as his Aristotelian predecessors in science claimed something is true simply because it is obvious.
Through the correspondence between Maria Celeste and Galileo, historians today have a deeper knowledge of Galileo's life and work. Galileo's Daughter exposes readers to his story – not just as a brilliant scientist, but also as a human being struggling with the boundaries of belief, religion and the idea of "truth" during his time.