> The PCM treats the orbits of two objects as circular, concentric, and coplanar. Keeping the coplanar assumption, in common with previous estimates, may be a

> The PCM treats the orbits of two objects as circular, concentric, and coplanar. Keeping the coplanar assumption, in common with previous estimates, may be a problem. Mercury happens to have an orbital inclination of 7°, second only to Pluto's at 1x7°. Mercury also orbits in an ellipse with an eccentricity of 0.21. Again, this is second only to Pluto, with an orbital eccentricity of 0.25. I'd like to see a model that takes into account inclination and eccentricity. For the most accurate model, the concentric assumption also fails. Strictly speaking, none of the planets orbit the sun. Rather, the sun and the planet both orbit the barycenter of the sun-planet system, and that will be different for each planet. While the difference is negligible for most planets, for Jupiter the barycenter is quite a distance from the center of the sun: at 1.07 times the diameter of the sun. That's just shy of 100,000km above the surface of the sun.