ON GRAVITY — OR MY WAY OF WISHING A BETTER NEW YEAR
(Rodrigo Peñaloza)

The word gravity comes from Latin gravitas, the quality of that which is gravis, an adjective that refers not only to what is heavy, it also refers to what or whom is pregnant. Indeed, she who is pregnant is also heavy. It is, therefore, a word intimately linked to the idea of generation through the idea of weight, as I will show through the following literary evidences. I hope they will enlighten us about our destiny to rise from falls.

Vergil, in The Aeneid, I, 272-274, uses the term gravis exactly in the sense of pregnancy:

"Here for full 300 years the Trojan people will reign, until the priestess queen Ilia, pregnant of Mars, gives to Ilia a progeny of twins".

(Hic iam ter centum totos regnabitur annos gente sub Hectorea, donec regina sacerdos, Marte gravis, geminam partu dabit Ilia prolem)

The reference of gravitas to weight appears in Lucretius, who, in the De Rerum Natura, II, 83-85, describing the movement of atoms in the generation of matter, says:

"Indeed, since they wander about in the vacuum, it is necessary that the elements of things be carried over, either by their weight or by the strong strike of the others".

(Nam quoniam per inane vagantur, cuncta necessest aut gravitate sua ferri primordia rerum aut ictu forte alterius)

To show that the use of this meaning was not isolated, it suffices to notice that Lucretius refers to the Democritus’s atomic theory and that such reference can also be found in Cicero’s De Natura Deorum, II, XXXVII, 93, in which Cicero ironically criticizes the atomic theory according to which matter is formed by the fortuitous encounter of atoms, not by an intelligent order:

"Would I by chance at this moment not be amazed by the existence of someone who persuades himself that certain solid and indivisible bodies are carried over by violence and weight and that the world be so adorned and beautiful thanks to the fortuitous shock of its bodies?"

(Hic ego non mirer esse quemquam qui sibi persuadeat corpora quaedam solida atque individua vi et gravitate ferri mundumque effici ornatissimum et pulcherrimum ex eorum corporum concursuine fortuita?)

Both authors, Lucretius and Cicero, speak of bodies that fall because of weight. It is however the propensity to fall due to weight that introduced the idea of attraction into the semantic amplitude of gravity. This meaning is new and came to life with the birth of modern Astronomy in the end of the 17th century. Newton, in the general scolium of the Principia Mathematica says:

"So far I exposed the phenomena of the heavens and of our seas through the force of gravity, but I have not yet assigned the cause of gravity".

(Hactenus phaenomena caelorum et maris nostri per vim gravitatis exposui, sed causam gravitatis nondum assignavi)

Newton then already conceives of gravity as a force of attraction. When Newtonian Mechanics was born, gravity acquired the meaning of attraction, since the word gravitas, the weight of bodies, began to be used to describe the idea that the celestial bodies kept their relative orbits because of the attraction they exerted over each other. From this it follows, as I think, that Newton, having no specific term for the force of attraction, chose to use the term gravitas or gravity, since the idea of the equilibrium of celestial bodies given by his Celestial Mechanics seemed to be explained by the fall of bodies one over the other. The weight of the bodies (or rather the mass, for what it is mathematically related to weight) would be so arranged as to make their respective velocities and positions – here I try to get into Newton’s mind – the perfect base for that celestial harmony that has enchanted our intellect since the very first time we raised our eyes to the infinite sky and in it we finally caught a glimpse of the greatest symbol of the Creator of All Things.

Why do we fear to be brought down by the force of gravity, if deep within, it gives to our fall a sense of generation, of hope, of a new self up to be born? No, gravity does not work against us, as wrongly says John Meyer’s song. It is rather a crucial element for our equilibrium. We only fall because we are pregnant of ourselves. May our falls this year bring better selves in the next.