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Mechanics
Kepler’s
Laws of Planetary Motion
The mathematician, Kepler analysed the data resulting from the
observations of the Danish astronomer Tycho Brahe. He summarised
his findings in three laws.
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Law 1
Each planet orbits the sun in an
elliptical path
with the sun at one
focus
of the ellipse.
Law 2
A line from the sun to a planet sweeps
out equal
areas in equal times.
Law 3
The
square of the time
period of a planet is
directly proportional to the
cube of its mean
distance from the sun. |
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1. |
The
elliptical orbits are
not very eccentric. They are
very nearly circular. |
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2. |
Law two
can be shown to be a direct result of he
law of conservation
of angular momentum. |
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3. |
Law three
is usually written |
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© David
Hoult 2008 |
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Open Door Web Site 