The supernova that challenged our worldview

On November 6, 1572, German astronomer Wolfgang Schuler of Wittenberg observed what he believed was a new star in the constellation Cassiopeia. On November 11, it was spotted by famed Danish astronomer Tycho Brahe. A.S.Ganesh tells you more about this “new star,” which we now know was a supernova…

The biggest explosion that human beings have ever seen, a supernova is what happens when a star reaches the end of its life and explodes in a brilliant ball of light. In recorded history, there have been less than 10 instances in the Milky Way when a supernova has been observed with the naked eye. One of those was in 1572 and it challenged and changed our existing worldview.

Today, astronomers refer to it by a number of names. The official name given to this supernova is SN 1572, where SN stands for supernova and 1572 corresponds to the year of occurrence. Some astronomers refer to it as B Cassiopeia. Most, however, call it by its informal name – Tycho’s supernova.

While supernovae have been observed for millennia, the one in 1572 remains one of the most significant cosmic explosions in terms of advancing our astronomical knowledge. While some claim to have observed this in August 1572, the first known observation of this for certain took place in November.

On November 6, 1572, German astronomer Wolfgang Schuler of Wittenberg noted the appearance of what he believed was a new star adjacent to the dimmest star at the centre of constellation Cassiopeia’s “W”. In the days that followed, it was not only spotted by skygazers, but literally everyone, as it practically became unmissable.

By November 11, it was spotted by Danish astronomer Tycho Brahe. While it was no brighter than an ordinary star when it was first noted, it was as bright as Jupiter by the time Brahe saw it. In the days that followed, it brightened to about the magnitude of Venus at its most brilliant and was even visible in the daytime for nearly two weeks.

It started slowly fading from the end of November but it wasn’t until March 1574 that it stopped being visible to the naked eye. Bearing in mind that the invention of telescopes were still decades away, follow-up observations after this were impossible.

While it was observed by many people, it is now known as Tycho’s supernova because of the work he undertook and the detailed study of its properties that he carried out. This came about during a critical phase in astronomy when the Ptolemic view of the universe (a fixed Earth is at the centre of the solar system, with everything else – the sun, moon, and planets – orbiting it) was challenged by the Copernican model, wherein everything orbited around the sun.