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Explorations an Introduction to Astronomy Thomas T. Arny | ||||||||
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Chapter
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Chapter 1, Figure 29
Figure
1.29
Kepler's
three laws. (A) A planet moves in an elliptical orbit with the Sun at one
focus. (B) A planet moves so that a line from it to the Sun sweeps out equal
areas in equal times. Thus the planet moves fastest when nearest the Sun.
(C) The square of a planet's orbital period (in years) equals the cube of
the semimajor axis of its orbit (in AU), the planet's distance from the Sun
if the orbit is a circle.
