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The "Hairy Ball" theorem explained

The "Hairy Ball" theorem explained

Ellsworth Toohey
Feb 20, 2025
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Boing Boing
Boing Boing
The "Hairy Ball" theorem explained
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Representational image (Boing Boing/Midjourney)

The Hairy Ball theorem, proved by Henri Poincaré in 1885, demonstrates that it's impossible to create a perfectly smooth hair pattern on a spherical surface.

The theorem states that any continuous pattern of hair (or more technically, vector fields) on a sphere must have at least one point where the hair eit…

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