Science in Dante’s “Purgatorio”

Dante’s Purgatory, described in the sequel to the Inferno, is a mountain in the South Pacific (the antipodes of Jerusalem). This painting by Agnolo Bronzino shows Dante gazing at the mountain:

Being in the Antipodes, the stars are naturally different, as all inhabitants of the Southern Hemisphere know:

Then I turned to the right, setting my mind
upon the other pole, and saw four stars
not seen before except by the first people.
Heaven appeared to revel in their flames:
O northern hemisphere, because you were
denied that sight, you are a widower!
” — Purgatorio, I, 22–27, tr. Mandelbaum

Dante has a nice description of time zones too (though with an average error of about two hours):

As when his earliest shaft of light assails
The city where his Maker shed His blood,
When Ebro lies beneath the lifted Scales
[i.e., midnight]
And noontide scorches down on Ganges’ flood,
So rode the sun; thus day was nightward winging
When there before us God’s glad angel stood.
” — Purgatorio, XXVII, 1–6, tr. Sayers

See also science in the Inferno and in the Paradiso.