The Strange Physics of the φ Top

This unique top is made of solid brass in the shape of a prolate elIipsoid- and the name of the top is derived from the following design requirement: the ratio of the semi minor (short) axis to the semi major (long) axis is made equal to the mathematical constant the golden ratio φ (phi).

Invented by astrophysicist Kenneth Brecher, this top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top.

The concave mirror keeps the top from wandering off and the glass surface has minimal friction allowing the top to spin for a long time- this video shows various stages of 8 minutes of total spin time.

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