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## General InfoEdit

### WhatEdit

Kepler's laws describe plantary motionlanet orbits

### Kepler's First LawEdit

A planet orbits the Sun in an ellipse, with the sun at one focus of the ellipse

### Kepler's Second LawEdit

A line connecting a planet to the Sun sweeps out equal areas in equal time intervals

$v^2 = G(m_1 + m_2)(\frac {2}{r} - \frac {1}{a})$

where $r$ is the distance from the principal focus

### Kepler's Third LawEdit

This law is also known as the harmonic law, relates the period of orbit to the average distance of the planet from the sun

$P^2 \propto a^3$

Using Newton's form of the equation, we get that

$P^2 = \frac {4 \pi^2}{G(m_1 + m_2)} a^3$

Note that the units of $P$ are in years and the units of $a$ are in AU