SOURCE: "Copernican Cosmology" in Circles of God: Theology and Science from the Greeks to Copernicus, Scottish Academic Press, 1985, pp. 200-57.

In the following chapter, Nebelsick discusses in detail Copernicus's contributions to astronomical research, including his theory of heliocentrism and his revision of the work of Ptolemy and other ancient astronomers.

The Development of "heliocentricity"

When and where Copernicus first began to think seriously about his "heliocentric" system is as difficult to ascertain as are his motives for developing it."⁵⁷ By the end of the fifteenth century Cracow had gained a reputation as a good place to study mathematics and astronomy. Hard times had fallen on the universities of Prague and Vienna with the result that a good number of peripatetic students and other interested persons brought their books and astronomical instruments to the city. Copernicus went up to the University of Cracow in 1491 to begin his study of...