I dont know whether anyone has approached the subject but is it possible that the elliptical orbit of the planets is expanding and placing planets nearer or further from the sun over time? In other words, are the planets also moving outward as well as orbiting? If that were the case then that could explain why Mars was apparently once like Earth and it would place Venus in Earths position at some future time perhaps Billions of years from now. Keplers Laws explain the elliptical orbit but as a stationary ellipse. But what if the ellipse was once a circle and has moved out to form an ellipse over time?