Someone tries to redo the Newtonian budget for Mercury's apsidal precession and…

PHYSICS · Multi-part · Fermi University Physics · Mathematical Methods for Physics · Mechanics & Dynamical Systems · Gravitation and central-force motion

Action and Symmetry, Ch Perturbed orbits, precession and the three-body problem

Problem

Someone tries to redo the Newtonian budget for Mercury's apsidal precession and argues: "Venus's mass is mV/M⊙=2.447×10−6m_V/M_\odot=2.447\times10^{-6}, and r/aV=0.3871/0.7233=0.535r/a_V=0.3871/0.7233=0.535 where rr is Mercury's orbital radius and aVa_V Venus's. Using the ring formula Δωp=3π2(mV/M⊙)(r/aV)3\Delta\omega_{\rm p}=\tfrac{3\pi}2(m_V/M_\odot)(r/a_V)^3 per orbit and Mercury's 415.2 orbits per century, Venus contributes 151.3151.3 arcseconds per century. Adding Earth's 90.090.0, Jupiter's 153.6153.6, Saturn's 7.37.3 and the small remaining terms (2.62.6) gives a planetary total of 404.8404.8 arcseconds per century. Subtracting from the observed 574574 arcseconds per century leaves a residual of about 170170 arcseconds per century, so whatever produces the anomalous precession must be about four times the standard 4343 arcseconds usually quoted." ((a)) Find the error in this working. ((b)) State the corrected planetary total and residual, using the published full-calculation value of 278278 arcseconds per century for Venus's contribution alone (the other planets' figures above are correct).

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