The YORP Effect

Since asteroids are basically just witless hunks of ice and rock, you'd think they'd live pretty boring, solitary lives. But you'd be wrong.

They pair up frequently, and become binary asteroids co-orbiting a central point. Sometimes they form threesomes. Woo-hoo! Sometimes they have tiny moons, tagging along after them. This picture is of Ida and Dactyl, an asteroid and its moon, but has always reminded me of a mother and child.


I love this picture. Dactyl is the little one.

Others hang around together in groups, often hitching rides in the LaGrangian points of planets (where the gravitational influences all balance out). i imagine them smoking cigarettes, whistling at girls, and trying to scrape up enough money for a six pack.

They also, improbably, begin to spin in the same direction, at the same speed, or specific resonances of that speed (it's called the YORP effect, named after the initials of the guys who figured it out). This has always struck me as particularly weird, that unrelated asteroids would mimic each other's orbital behavior. Apparently it has something to do with the pressure of sunlight on the surfaces of the asteroids, so that like sailboats on a lake, they'll all react similarly to the solar wind. But i like to think of it as a complex dance. It heartens me to realize that the universe rarely allows things to work alone as independent operators, whether those things be space rocks or ants or humans. I don't wanna say that randomness doesn't exist. Randomness is all. But from randomness spring unexpected patterns, complex structures, and hopelessly entangled relationships.

We are never, ever alone.

Even when we wanna be.