Tag: Ellipsoid

On Descriptive Geometry

I keep forgetting I am writing for an international audience here! Having referred to Descriptive Geometry (DG) often, I doubt that everybody associates similar mental images with it. Anybody remembering the trace of a plane, for example? Learning about the history and culture of Descriptive Geometry, I realize it is rooted in a European tradition…
Rolling Not Slipping – Story of a Twirling Ellipsoid

I can’t help it – I use the first title that pops into my mind! “Rolling, not slipping” is the punchline of a mathematical argument used in classical mechanics, in the theory of the motion of a gyroscope. But I am not going to do it justice in this blog post (apart from a math…
Friendly Sparkling Alien Spaceships

I know, I am again using this metaphor! But once I saw the friendly alien spaceships in these images, I could not unsee them! There is more background information about these sparkling ellipsoid and spheres in my previous post. Today I only want to show you number 2 and 3 in this series of four…
Poinsot’s Paper Spaceship (2025)

I’m presenting the recently completely series of artworks – and related physics blog posts – in its entirety! An ellipsoid is intersecting a sphere. Their intersection line is where the vector of angular momentum is seen to travel along – from the perspective of the spinning gyroscope. Four geometrical drawings, each based on the physics…
Geometry of the Physics of the Gyroscope – on a Coffee Mug!

Construct the Labyrinth from Which You Plan to Escape … has been the motto of the Oulipo movement, French writers and mathematicians who have boosted their creative writing by imposing arbitrary constraints. I had practiced Oulipo long before I knew the term. I just called it Search Term Poetry or Spam Poetry. I have been…
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…
Ellipsoid Intersects Sphere – Digital Edition in Progress

I call my current series Poinsot’s Paper Spaceship for a reason: There is also Poinsot’s Pixel Spaceship in the making! Same physics, same idea! The motion of a force-free gyroscope can be described by an ellipsoid intersecting a sphere: The curve of intersection is the path the vector of angular momentum traces out – from…
Poinsot’s Paper Spaceship #1 – UFO

Louis Poinsot has a crater on the moon named after him … and now, also my series of geometrical drawings. I am taking the ellipsoid and sphere to the third dimension, based on the plan laid out before. Number 1 is an oblate ellipsoid, intersecting the sphere nearly in two circles. It is a classic…
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…