the.com/spin axis
the invisible line a spinning thing insists on rotating around, whether you asked or not.
means the imaginary line through an object's center of mass around which it rotates.
from from classical mechanics: any rotating body has a moment of inertia and, absent outside torque, that spin persists around a fixed axis - the same principle that keeps a thrown football tight and a planet's seasons on schedule.
earth's tiltaxis leans 23.4 degrees, giving us seasons
wobbleearth's axis drifts, called precession, over 26000 years
gyroscopesresist axis change, which is why they navigate rockets
bulletsrifling spins them for axis stability in flight
for instance
earth precession — pole star will be vega again in about 12000 years
gyroscope compass — used in submarines and spacecraft since early 1900s
spinning top — axis tilts and traces a cone as it slows
neutron star psr b1937 — spins on its axis 641 times per second