SOURCE: "The Comet of 1577 and Tycho Brahe's System of the World," in Archives internationales d'histoire des sciences, Vol. 29, No. 104, June-December, 1979, pp. 53-67.

In the following excerpt, Thoren explores the development of Brahe's cosmological system after his observance of the comet of 1577 until his publication of De mundi in 1588.

Although Tycho's system of the world has traditionally been associated with the comet of 1577, the connection between them has been treated by most commentators as essentially circumstantial: the two have been discussed in the same chapter because Tycho published his accounts of them in the same book, his De mundi aetherei recentioribus phaenomenis of 1588. Only rarely has even the logical relationship between the two—the fact that they represent parallel challenges to the cosmological assumptions of Aristotle and Copernicus—been pointed out. And the historical links between the two have never been satisfactorily explained. Not surprisingly, this problem stems in...