Tennis racket theorem
Teorema del eje intermedio
- Date
- 1834 (Poinsot) / 1985 (efecto Dzhanibekov) · confidence medium
- Place
- Paris, France
- Credited to
- Louis Poinsot (described in 1834); popularized as the Dzhanibekov effect after cosmonaut Vladimir Dzhanibekov observed it in 1985
- Field
- Cosmos & Earth
What was discovered
A classical-mechanics effect by which a rigid body spins stably around its major and minor principal axes, but unstably and unpredictably around the intermediate axis, as seen when a tennis racket is tossed in the air.
The phenomenon was known since Poinsot (1834); Dzhanibekov made it famous after observing it aboard the Salyut 7 station in 1985.
What it led to
- an explanation of why a freely rotating object abruptly flips its spin axis
- popularization as the "Dzhanibekov effect" after being observed in zero gravity in 1985
- consideration in spacecraft and satellite design to avoid unstable tumbling
- a standard example in teaching rigid-body mechanics