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Dante's Astronomy

Peter Lord


“Amateur astronomers are heirs to an epic legacy of personal exploration ....”


Dante and Beatrice reach the sun. Giovanni di Paolo, 1403 - 1483.


Dante's great masterpiece The Divine Comedy embodies a transcendental form of astronomy. Each of the three books of this epic medieval work begins with the upward look to the heavens in Greek tradition of the astronomer/philosopher. Just as significantly, each of the three books ends with the word Stelle, or stars. The last thought that this great poet leaves the reader with, is that his mind revolves with the love that moves "the sun, the moon, and other stars." There is no question that The Divine Comedy was conceived by a genius aflame with the passions that inspire amateur astronomers to this day; aperture fever is something Dante Aligehiere would have understood completely.

To fully appreciate Dante's use of astronomy, we need to remember that 700 years ago astronomy and philosophy remained tightly integrated within the liberal arts of the first universities Oxford and Paris. This was the astronomy of Ptolemy, preserved by the works of Arab astronomers, a legacy that lives today in names such as Deneb, Aldebaran, and Alfraganus. Dante's pre-Copernican astronomy, was essentially a Greek system in which the stars and planets rode across the heavens on crystalline spheres set in motion by the hand of God. It was a pure form of naked eye astronomy, philosophically born of the primal human urge to explore, an impulse we still feel today as we look up at the stars and question the meaning of our existence.

Dante's astronomy brings to life the ancient philosophical tradition that looking to the stars in contemplation transforms and elevates the mind. Perhaps the finest example of this occurs in the beginning of Dante's second book, The Purgatory. Here after emerging from the subterranean confines of Hell (where one cannot look at the stars) Dante and his mentor Virgil pause from their climb up the mountain of Purgatory. They rest on an East-facing ledge in the early hours after dawn. Dante reveals his observational skills by noticing something unusual about the path of the sun through the sky. He turns to Virgil in amazement, perplexed that the sun is moving to the left of the meridian. Dante who started his journey in the northern hemisphere expects to see the sun moving to his right, to the south of the meridian. Within the works that Dante studied was a reverence for the fact (considered highly philosophical in a world without satellites) that the heavens appear to behave differently from different vantage points on a spherical earth. What Dante is coming to terms with is that his subterranean journey across hell took him straight through the earth, past its center, and up into the southern hemisphere.

Virgil asks Dante to remember all that he studied, then work out the significance of what he is seeing. In a sudden flash of understanding any amateur astronomer knows well, Dante "gets it:" he is seeing the motion of the sun from the other side of the world! As soon as Dante turns his mental worldview upside-down, it all makes sense. Dante brings to life the power of astronomy to transform our worldview (the very foundation of our experience of life on planet Earth) through poetry.

A second remarkable example can be found in The Paradiso as Dante reaches the crystalline sphere that carries the sun. Here, he pauses to gaze lovingly on the geometric points of the equinox before him. Describing with mathematical skill the intersection of the ecliptic with the other great circles of the Ptolemaic astronomy. Dante fills his poetry with the appreciation that the skewed relationship of the circles is the cause of the Earth's seasons.

The Divine Comedy reminds us not only of the tremendous power of visual astronomy to inspire us; it also reminds us that the wonder and inspiration that we find in astronomy links us to some of the deepest philosophical questions of the western tradition. The Divine Comedy further entices us with the prospect of entering into this tradition through our own education. The light of Dante's intellect has the power to transform our own upward gaze to the stars into a celebration of our shared humanity. Amateur astronomers are heirs to an epic legacy of personal exploration, hidden in one of the foremost works of western literature, waiting to be noticed like the stars above.

— Peter Lord

[Editor's Note: Peter Lord is a long time member of SJAA, PAS, and other Bay Area astronomy clubs, a spacecraft engineer for Loral, and recent recipient of a Masters of Liberal Arts from Stanford. His thesis explored the astronomy in Dante's Divine Comedy.]


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