Initially, in the mid 1960s, other respected astronomers said that it wasn't possible that these two moon-lettes had achieved a stable orbital equilibrium (i.e., that they could occupy the same orbital space and plane, without an eventual cataclysmic collision occurring). But the usually wise astronomers were. . . wrong. They could; and they do.
The pair orbit in what are best described as horseshoe shapes (see lower image); in fact, the two end up trading orbits each time they pass near one another. That is generally what a shepherd moon does: it corrects the orbit of the shepherded moon. In this case, though (unique in all our Solar System, we believe), each. . . perfects the other. That is. . . simply amazing -- and poetic.
So -- let us listen in a bit then, on a resonant poem -- for Epimetheus -- the sibling of Prometheus (and, in this case, the star-swept occasional partner -- to Janus, the other Saturninan moon in this orbital space). From this fine longer poem, called "Waterlilies Soon And A Pleiku Of Dragonflies" a bit -- with edits (original author: Patrick White), then:
. . . .Waterlilies soon and a Pleiku of dragonflies.
Shipwrecked fleets of naked limbs. . .
buried at sea -- wrapped
in a starmap of the sky. . . .
I will forget I am aging. I will be a medicine bag
of healing metaphors and powerful occult charms. . . I will
lie down upon the earth in the unassuming grass
after I’ve finished painting, fascinated by the. . .
stranger I’ve become to myself, listening deeply
to the picture music of the life of the mind like a kid
with forty-eight crayons and the whole of the sky to draw on
as I wait for the stars to make themselves apparent
in the [copper-colored] flames and [deep-]violet shadows of another
[exquisite] martyr -- to the cause of keeping their fires alive within me,
a dragonfly in a chrysalis, a hermit thrush in ecstasy,
a sulphur butterfly with antennae like burnt match sticks
looking for a light from the lanterns of the nightwatch
reigniting the passions of old poems like fireflies
inspiring the ashes in the urns of the stars to enlighten their afterlife. . .
fracturing koans like diamond insights into
a labyrinthine gallery of mirrors that see me
with the same eyes by which I see signs
of the disastrous happiness of life in them. . . .
And with that, I will quite easily drift off to sleep, shepherded once more, by my own moon-lette -- somewhere, to the South, out there. . . smile. G'night.