Science Goes to Hell: Dante's Gravity and Lucifer's Math

Lucifer trapped in Earth's core.
Lucifer trapped in Earth's core.
Giovanni Stradano, 1587

There are so many reasons to love Dante's "The Divine Comedy." It's a crash course in medieval Christian theology, a 14th century dirt sheet, a smorgasbord of history and a journey into an amazing mind. Plus you get fearsome monsters, bawdy demons and -- yes -- medieval science!

Dante wrote "The Divine Comedy" in the common language of Italian rather than the Latin of the upper class. This way it reached the masses and did so without the aid of someone else's inept translation. To quote Alison Cornish in "The Vulgarization of Science," Dante made it his business to "integrate learning into the vernacular forms, and to make it accessible even to the unschooled."

As such, Dante poured a fair amount of science into his masterpiece. So I thought it'd be cool to run through a few examples.

Gravity in Hell

"Inferno" sees Dante descend deeper and deeper into Earth's interior (here's the map), toward the very center of the planet. He encounters constant historical figures and contemporary celebrities along the way, but gravity doesn't appear to change.

Gravity, of course, has everything to do with mass. Geophysicist Fred Duennebier points out here that a journey into the depths of the Earth wouldn't change things for you. There'd be less mass underneath you pulling you down, but there'd still be all that mass overhead to balance things out.

It gets really interesting when Dante and his guide Virgil make it to the very center of the planet, where Satan is trapped in a frozen lake. In fact, Dante's Inferno puts the exact core at Satan's groin region. Dante and Virgil escape Hell by climbing down the devil's furry flanks -- and then down suddenly becomes up. You can read the whole passage here.

Naturally, such a feat would be impossible for any number of reasons -- the least of which being that the center of the Earth is a solid mass. But the manner in which Dante depicts the exact center as a kind of zero point actually carries some scientific weight. Here's what NASA has to say:

"Forces add like vectors, so their direction is very important. If you could be at the exact center, the forces that each bit of Earth matter exerted on you would cancel out (up canceling down, east canceling west, etc.). This only occurs for a single point, though, and you would still feel a gravitational force on the rest of your body." -- Angela Richard

Of course, as modern Professor Andrew J Simoson points out in "The Gravity of Hades," Dante might have found some inspiration for this encounter with hell's gravity by reading first-century writer Plutarch's "Moralia." Plutarch, however, basically just said, "hey, what if a man's navel were the center of the Earth?" Dante's the one who decided to get the devil involved.

Lucifer Falls through the Milky Way

Ever eager to apply science to theological quandaries, Professor Simoson is a mathematician after Dante's own heart. In the aforementioned article, he discusses an interesting mathematical thought experiment: could one apply modern math, physics and astronomy to Milton's "Paradise Lost" to estimate the "Miltonian distance between Heaven and Hell?"

Naturally, Lucifer's fall from Heaven is the perfect measuring stick for this and Simoson spends several pages applying real-world equations to a 17th century take on the devil's origin story. YOU might never stop to wonder whether the speed of a falling angel should be constrained by the speed of light -- nor the state of the galaxy during that time, but Simoson has it all covered.

I'll leave it to you, gentle reader, to ponder a future in which interstellar space ships depend on falling angel-based propulsion systems.

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.