For 10 points, name this phenomenon where the axis of a rotating object changes direction, which can be applied in astronomy to Earth's changing axis as it revolves and rotates.
NMR-related imaging is based on the fact that resonant frequencies of nuclei experience the Larmor type of this and are proportional to magnetic field strength. For the torque-induced type, one can calculate velocity of this by dividing torque by spin angular momentum, a quantity often computed for the gyroscopic type and important in gyrocompasses. For 10 points, name this phenomenon where the axis of a rotating object changes direction, which can be applied in astronomy to Earth's changing axis as it revolves and rotates.
NMR-related imaging is based on the fact that resonant frequencies of nuclei experience the Larmor type of this and are proportional to magnetic field strength.
{precession}