Kepler's Third Law

    Planet        Semimajor      
    Axis, a
    Orbital      
    Period,
    P
    P2/a3
    (AU) (years)
    Mercury 0.387 0.241 1.002
    Venus 0.723 0.615 1.001
    Earth 1.000 1.000 1.000
    Mars 1.524 1.881 1.000
    Jupiter 5.203 11.86 0.999
    Saturn 9.537 29.42 0.998
    Uranus 19.19 83.75 0.993
    Neptune 30.07 163.7 0.986