Ptolemy and the Shape of the Universe with Dr. Henry Zepeda

“The heavens call to you and wheel about you,

revealing their eternal splendors,” Virgil told Dante at the end of Purgatorio 14 (148-151),

“but your eyes are fixed upon the earth.

For that, He, seeing all, does smite you.”

While we could blame light pollution or television or lack of interest or any number of other modern maladies, but it’s clear that, just as in Dante’s time, the heavens call and wheel about and us most of us never notice. If, for example, you know the phase of the moon today, you’re part of a tiny, tiny minority of modern people. Virgil accuses us as well, “your eyes are fixed upon the earth.”

Dante lived at the turn of the 14^th century and in his writing used a model of the universe conceived in the second century by astronomer and mathematician Claudius Ptolemy. Born in AD 100 in Alexandria, Egypt, Ptolemy argued from observation of the heavens that the earth (a sphere) was at the center and around it the moon, sun, planets, and stars rotated.

Clearly we no longer believe that, but Ptolemy still has a great deal to teach us about observing the sky and marking it’s beauty and regularity. Dr. Henry Zepeda taught Ptolemy, Copernicus, and Galileo with high school students who have been here at Wyoming Catholic College for our PEAK Program.