RevolutionsOfAnIrregularSolid

Not long ago as I began to reread Middlemarch I hit a sentence that could only derail a theoretical physicist's train of thought. At the end of Book I Chapter 4 the protagonist's fusty uncle is confounded by his niece's decision to marry:

In short, woman was a problem which, since Mr. Brooke's mind felt blank before it, could be hardly less complicated than the revolutions of an irregular solid.

Complicated, but also completely understood (the solid, that is!). An arbitrary irregular object tumbles as it rotates, performing an aperiodic ballet described by Jacobi elliptic functions. The precession of a symmetric spinning solid such as a toy top is a straightforward special case. Herbert Goldstein whimsically encapsulates rigid-body motion in his famous (or infamous, if you had to study it) textbook Classical Mechanics (1950):

Hence the jabberwockian sounding statement: the polhode rolls without slipping on the herpolhode lying in the invariable plane.

It actually makes sense, but only after one struggles through a flock of definitions and derivations. George Eliot, however, has more complex fish to fry — human nature — so she wisely ends her chapter with Mr. Brooke's befuddlement ... and no equations.

(cf. SpinningSources (11 Apr 2000), QpoLmxb (8 Jan 2001), ...)


TopicLiterature - TopicScience - TopicHumor - Datetag20060321


(correlates: MandatoryInversion, HerodotusOnTheSpartans, RuleOne, ...)