Galileo confirmed as author of pseudonymous 17th century astronomy text

We reported in August that a letter written by Galileo Galilei in the University of Michigan's library was a forgery. Another discovery has been made by the investigation. A 17th century book on astronomy was written by Galileo under a different name.

The Michigan letter purported to be a draft of a letter that Galileo wrote to the doge of Venice in August of 1609. The final letter is located in Venice. Wilding was working on a biography of Galileo when he became suspicious of the manuscript's authenticity.

The ink and paper of the manuscript were found to be consistent with the period when Galileo made his observations, but there was no hope of authenticity after Wilding's investigations. Galileo's discoveries were 150 years after the documents were found.

Libro della Considerazioni Astronomiche di Alimberto Mauri.">

The Michigan letter was signed by a Cardinal from Pisa. Maffi used the documents in the cardinal's collection to compare them. These were also found to be forgeries. One of them was believed to be the author of the 1606 treatise, Libro della Considerazione Astronomica. The text argued for the existence of mountains on the moon as well as other insights.

Shortly after it was published, there was a suggestion that Galileo wrote it. According to Matteo Cosci, a historian at Ca' Foscari University of Venice, one of Galileo's University of Padua colleagues described the pseudonymous Mauri as someone who wanted to be an astronomer.

He used pseudonyms. He was involved in a debate over the topic of the 1604 supernova under the name Cecco da Ronchietti. The new star wasn't new, but it was always there, according to the philosopher. The Ptolemaic model of the solar system had fixed stars. At the time, Galileo was a professor at the University of Padua. He thought it was a new phenomenon, not a permanent star, and even suggested possible mechanisms by which it could have been produced.

Delle Colombe's thoughts on the "stella nova" were based on both astronomy and philosophy. Considerazione Astronomica was published a few months later.

Delle Colombe didn't identify Galileo as his opponent. He referred to the professor as "Mr. Mask" in his Risposte piacevoli e curiose. A student wrote "Galileo Galilei" under the title of his book.

In the 70s, scholars cited the Maffi letter as proof that Galileo wrote Considerazione Astronomica. The archives at the Biblioteca Nazionale Centrale in Florence hold a collection of Galileo's handwritten notes.

Risposte to the pseudonymous A. Mauri.">

He found the strongest evidence for Galileo's authorship of Considerazione Astronomica, which was a list of places where dell Colombe spoke of him with contempt. The "places" were references to certain passages in the Risposte, but when Cosci looked them up, they were attacking a different person. According to Cosci, Galileo wouldn't have felt attacked personally unless he was, in fact, Mauri.

A handwritten note by Galileo indicated that he was considering another reply but decided it was not worth his time. They were still arguing about the motion of the Earth years later, but Galileo was famous and no longer needed a pseudonym. The historian is working on a new edition of Considerazione Astronomica that will show how similar Galileo's other writings are.