See part one here

Thirty years after that supernova made its remarkable appearance in Earth’s skies, the Danish astronomer Tycho Brahe would recall his first sight of it:

Amazed, and as if astonished and stupefied, I stood still with my eyes fixed intently upon it. When I had satisfied myself that no star of that kind had ever shone forth before, I was led into such perplexity by the unbelievability of the thing that I began to doubt my own eyes.

Like John Dee and Francis Bacon in England, Tycho knew that according to the Ptolemaic system that had been firmly in place for hundreds of years, the real problem was “that [the supernova] was in the celestial, not the Elementary Region” — that is, that is was not within the cycles of the planets, which were known to move and change (the word “planet” means “wanderer”) but in the more distant realm of the so-called “fixed stars,” the supposedly unchanging backdrop to the celestial machinery. Whether or not the exploding star was a God-sent sign to King Charles of France or not, it was a powerful blow to the Ptolemaic system.

In a lucid essay on this event, the noted astronomer Owen Gingerich writes that “Tycho had, first of all, the imagination to formulate an interesting research strategy, secondly, the ingenuity to devise the instruments to carry out the research, and thirdly, the ability to draw significant conclusions from his results.” John Dee may have understood the general import of the event but only Tycho went about exploring it in a serious way. Gingerich is interested primarily in the technical challenges that Tycho faced, and triumphantly met, but he notes in passing that the Cassiopeia nova “was by no means the end of Aristotelian cosmology, but it was the beginning of the end.”

This is perhaps an understatement. C. S. Lewis in his The Discarded Image comments that “the great Nova in Cassiopeia of November 1572 was a most important event for the history of thought.” Lewis points to F. R. Johnson’s 1937 book Astronomical Thought in Renaissance England: A Study of the English Scientific Writing from 1500 to 1645 — which is still worth reading, by the way — for evidence that the community of natural philosophers in England at least, and presumably elsewhere, were deeply shaken by the nova’s appearance.

It’s a really fascinating moment in intellectual history. The Ptolemaic theory was already being challenged and would in any case have eventually fallen, but this single event did more rapid and serious harm to it than any articulated theory could have. A whole system of belief was effectively brought to its knees by a few incontrovertible astronomical observations.


  1. Very interesting. However, as much as this event (the supernova) may have coincidentally shook foundations of intellectual thought in the 16th century, Oswald Spengler in particular suggested that the Classical number of antiquity (including the Ptolemaic system) was already in the process of being supplanted by what became the Cartesian coordinate system. The number of Enlightenment thinkers all coalescing around the same set of ideas, which are partly intuited through vivid experiences and expressions of faith, points to a very different thought-world then emerging: abandonment of sensual epistemology in favor of a purely abstract or absolute way of understanding relationships.

  2. brutus, I don't believe the Cartesian coordinate system appeared in any form until fifty years or more after this supernova appeared. Do you have alternative information?

  3. You were discussing a fundamental shift in epistemology, which is a process, not an event. Takes time to happen and to recognize. The start of the shift to the heliocentric view began well before Descartes, who later formalized the resulting disappearance of spatial anchors (earth no longer at the center of the universe).

    That said, I'm repeating (imprecisely, no doubt) what I read from Spengler. It's a sophisticated argument of which I'm getting only a portion.

    Also, Adam Frank wrote a book related to our orientation in time-space called About Time: Cosmology and Culture at the Twilight of the Big Bang. It shows that technological advance stimulates adoption of updated metaphors for our fundamental assumptions about reality.

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