The Ophiucus Supernova
Post-Aristotelian stargazing in the European context (1604-1654)


In October 1604 a giant supernova unexpectedly exploded in the constellation of Ophiucus and its bright light remained visible to the naked eye for many months. At first it was regarded as the insurgence of a “new star” or stella nova, although it was actually a “dying” star or a “supernova”, as today we know. At that time, however, the sudden appearance was an anomalous and stunning event for those observers that conceived the stars as “fixed” and the heavens as unalterable - the accepted position in physics and astronomy at that time. Astronomers as well as astrologers and other stargazers tried to explain the nature and significance of the novelty.

The interpretation of the new star was one of the main speculative battlefields where opposing conceptions of the universe collided and its presumed origin was debated at length, from Galileo’s first astronomical studies (1604), passing through Kepler’s magnum opus on the subject (1606), to Giovanni Battista Riccioli’s exemplary synthesis fifty years later. As in the case of Tycho’s supernova in 1572 and of the great comet observed in 1577, the appearance of the supernova was deployed as a direct challenge to the physics and cosmology of Aristotle, at a time when all contemporaries either accepted Aristotle’s views or had originally been trained in them. For a growing number of scholars, the supernova of 1604 disputed Aristotle’s doctrine that the heavens and the earth were absolutely distinct, and that all sorts of change could occur only in the region below the moon.

The 1604 supernova appeared from nowhere, outshining the planets before declining in brightness and finally disappearing. This should have been impossible for a star, and some interpreters preferred to view it as a meteorological event in the upper reaches of the air. But measurements established that the new object was beyond the moon’s sphere, hence part of the heavens, and hence impossible according to Aristotle’s cosmology. In addition to occasional observers and extemporaneous writers, the interpretation of the supernova involved the most renowned astronomers of the time, some of whom saw it as salient evidence against Aristotle’s theories and in favor of the new astronomical alternatives supported by Kepler and Galileo.

Kepler's Supernova Remnant (SNR). Composite image. Credits: NASA/ESA/JHU/R.Sankrit & W.Blaire

The Ophiucus Supernova: Post-Aristotelian Stargazing in the European Context (1604-1654) is a research project funded under the REA’s Marie Curie fellowships scheme to Dr. Matteo Cosci (P.I.), researcher at the University Ca’ Foscari Venice, Italy. This research will examine how the unexpected explosion of the “Kepler’s supernova” in European skies in 1604 fundamentally affected the development of Renaissance scientific thought from a historical, philosophical and cultural point of view. The study will be grounded in an extensive set of primary sources and documents assembled and analysed in their entirety for the first time.

The first phase of research will be conducted at the Department of History of Science at University of Oklahoma, while the return phase will take place at the Department of Philosophy and Cultural Heritage at Ca’ Foscari University, Venice. The study will also provide data to, and will be assisted by, the Terra-Astronomy research group, based at the University of Jena, Germany.


Matteo Cosci’s project (2021) is being conducted at Ca’ Foscari Dipartimento di Filosofia e Beni Culturali in partnership with the the Department of History of Science at University of Oklahoma.

It benefits from ongoing collaborations with:

For more information on researching Renaissance philosophy at Ca’ Foscari, follow the activities of the Center for Renaissance and Early Modern Thought (CREMT).