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KEPLER ANNIVERSARY by F. Michael Witkoski
58 AUGUST 2019 • SKY & TELESCOPE
This year marks the
400th anniversary of
Kepler’s Third Law of
Planetary Motion.
Planets
Governing
the
POLYHEDRAL SEPARATION
Kepler’s model of the solar system
relied on Platonic solids — im-
mutable polyhedra nested inside a
series of spheres thought to carry
the planets.