Geometry of the Motion of a Free Prolate Gyroscope (and the Power of Magnets)
How should I spin the story of the gyroscope this time? Imagine, you have a wonderfully crafted elongated ellipsoid from wood (shaped like a rugby ball). You built some apparatus that make it spin fast about its major axis. Probably you can make it spin with your bare hands - or you ask a tentacled alien for help. The symmetry axis of the body, the axis of rotation, and the vector of angular momentum are all aligned. You or the alien or the apparatus fling the ellipsoid into the air, […]#louispoinsot — Public Fediverse posts
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Bumblebees and Ellipsoids (Poinsot’s Paper Spaceship #3)
In the movie Ice Age, Manny the Mammoth says he is not fat - just poofy! It is just the fur! I feel the same must be true for bumblebees - they are fluffy, but not really fat! And yes, these were the things going through my mind, when I created this geometric drawing: A sphere is intersected by a "fat" ellipsoid that is neither an oblate UFO nor an elongated zeppelin. Poinsot's Paper Spaceship #3 - Bumblebee by elkement 2025. Geometric drawing of an ellipsoid intersecting a sphere […]https://elkement.art/2025/07/25/bumblebees-and-ellipsoids-poinsots-paper-spaceship-3/
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Poinsot’s Paper Spaceship #0 – The Plan
There was a time before computer-based three-dimensional visualization. There was a time before any software at all. When James Clark Maxwell sculpted thermodynamic functions with clay. When Louis Poinsot described the motion of the gyroscope in terms of three cones embracing each other, boiling down the essence of a free spinning top's motion. Today, we feed software the differential equation governing the motion of a rigid body - or talk to an AI bot soon - and produce a movie of the […]https://elkement.art/2025/06/20/poinsots-paper-spaceship-0-the-plan/