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scribe ellipses with the sun at a focus of
each ellipse.
His second law (a far more difficult one
to prove) states that a line drawn from a
planet to the sun sweeps over equal areas in
equal times. These two laws were published
in his great work, Astronomia Nova, sen.
Physica Coelestis tradita commentariis de
Motibus Stelloe; Martis , Prague, 1609.
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