Kepler's 1st law: Difference between revisions

Revision as of 15:47, 18 March 2020

Johannes Kepler (b. 1571)

Kepler's laws of planetary motion 1609-1619

The orbit of every planet is an ellipse with the Sun at one of the two foci.

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+'''Johannes Kepler''' (b. 1571)
+''''' Kepler's laws of planetary motion''''' 1609-1619
 The orbit of every planet is an ellipse with the Sun at one of the two foci.
-Mathematically, an ellipse can be represented by the formula:
-$${e r={\frac {p}{1+\varepsilon \,\cos \theta }},}{\displaystyle r={\frac {p}{1+\varepsilon \,\cos \theta }},}$$
-where $$p$$ is the semi-latus rectum, ε is the eccentricity of the ellipse, r is the distance from the Sun to the planet, and θ is the angle to the planet's current position from its closest approach, as seen from the Sun. So (r, θ) are polar coordinates.
-For an ellipse 0 < ε < 1 ; in the limiting case ε = 0, the orbit is a circle with the Sun at the centre (i.e. where there is zero eccentricity).