How a 1604 supernova rewrote the astronomical playbook
Sometime in October 1604, the night sky was suddenly lit up by a bright light – and with it a new scientific debate was ignited. “Although today we know that the light was caused by a dying star, or supernova, at the time it was believed to be the birth of a new star,” says Matteo Cosci, a researcher at the Ca’ Foscari University of Venice, Italy. As Cosci explains, this belief was a direct challenge to the accepted doctrine, established by Aristotle, that stars were fixed and the heavens unalterable. “Measurements established that the new object was beyond the moon’s sphere and hence part of the heavens and thus impossible according to Aristotle’s cosmology,” he adds. It didn’t take long for the battle lines to be drawn, with names such as Galileo and Kepler arguing in favour of a new astronomical paradigm. But how exactly did this debate unfold and who contributed what? With the support of the EU-funded SN1604 project, Cosci aimed to find out. “We wanted to understand how those almost forgotten observations of the 1604 ‘stella nova’, as it was then called, contributed to the abandonment of the centuries-old Ptolemaic-Aristotelian view of the heavens,” explains Cosci.
Two pseudonymous works attributed to Galileo
To start, the project, which received support from the Marie Skłodowska-Curie Actions programme, looked at the surviving records on the phenomenon. Researchers conducted a survey with a particular focus on the two most accredited observers of the time, Galileo and Kepler. Following intense and systematic archival research, the project was able to attribute two pseudonymous works about the 1604 event to Galileo. “Both works were published in the aftermath of the astronomical event, when Galileo was teaching mathematics in Padua and opposing his many Aristotelian adversaries,” notes Cosci. The first and shorter work was published under the name Astolfo Arnerio Marchiano, while the second, longer piece was published under the name Alimberto Mauri. Together with a third pseudonymous discourse already attributed to Galileo, these three works offer a unique insight into the new star event of 1604. For example, we now know that Galileo knew exactly where and what he wanted to watch for in the heavens, even before he first pointed his telescope towards the sky.
A long list of works about the 1604 supernova
According to Cosci, these works by Galileo are just two in a long list of neglected works about the supernova that need to be studied. “A galactic supernova is one of the rarest events in history, with the 1604 event being the last to be visible to the naked eye,” he explains. “No wonder nearly everyone had something to say about it!” Cosci is currently working on a critical edition of several records on the 1604 event, as well as writing a monograph on Galileo and the supernova. He also plans to conduct a comparative study between Galileo’s and Kepler’s approach to the same astronomical event. Last but not least, he hopes to study the readaptation and decline of Aristotelianism in the 17th century, an irreversible process whose beginning can be seen in the 1604 celestial novelty. “We don’t know when the next supernova will be visible to naked-eye observers,” concludes Cosci. “When it does happen, I hope scholars and novices alike can appreciate the eventful story from 1604, when a bright light suddenly lit up the sky and eventually rewrote the astronomical playbook.”
Keywords
SN1604, supernova, Galileo, Aristotle, stars, cosmology, Kepler
