In English, "moments of inertia" might be taken to be points in time with little motion, or with continuing motion. In physics, a moment of inertia has to do with angular momentum, a tendency of an object to rotate at a frequency related to the distribution of its mass from the axis of rotation. (A spinning figure skater pulling her arms in will speed up with no further effort.) Both of these meanings seem relevant. In this piece, or at least in the first two movements, I can imagine a spinning skater moving her arms in curious ways, spinning fast and slow, while remaining in one spot on the ice.

In the first movement, "With quiet turbulence," the meter is defined by a simple melody in the flute, while the viola and cello background motive implies something else. The conflict results in a curious sense of both motion and stasis. The compulsive background motive eventually commandeers the entire movement, insisting upon its own meter, with several possible downbeats for the ear to choose from. "Uneasy lullaby" gently rocks between 6/8 and 3/4, a simpler sort of ambiguity. "With headlong agitation" tosses all ambiguity to the wind with relentless forward motion.

Moments of Inertia was commissioned by Dinosaur Annex for its 26th season.