1. Mercury: lattice density implied by (5.9)
   Aspden's inputs (38"/cy, P 3.27e26 g, X 5.7e12 cm, R 2.495e8 cm, 88 d): 143.8 g/cc (he wrote 'about 150'; ch. 6 lattice gives 144)
   today's inputs (42.98"/cy, P 3.3011e26 g, a 5.7909e12 cm, R 2.4397e8 cm, 87.969 d): 189.6 g/cc
   to keep 144 g/cc the lattice boundary must sit at 1.1622 x Mercury's radius
   the 38"/cy rested on Dicke's 1967 solar oblateness; helioseismology gives J2 = 2.2e-7, worth only 0.03"/cy

2. Sign check: integrate (r^2 - k) dtheta/dt = L with Newtonian radial force
   k/a^2 = 0.0001: perihelion moves -1.370e-03 rad per orbit; (5.9) magnitude 4 pi k/a^2 = 1.257e-03  -> REGRESSION (backward)
   k/a^2 = 0.001: perihelion moves -1.370e-02 rad per orbit; (5.9) magnitude 4 pi k/a^2 = 1.257e-02  -> REGRESSION (backward)

3. Same mechanism, same 144 g/cc, applied to the other planets (lattice boundary 1.1 x radius)
   planet     GR "/cy   Aspden "/cy     ratio   boundary needed for GR value
   Mercury     42.980         32.65      0.76   1.1622 x radius
   Venus        8.625         23.32       2.7   0.9016 x radius
   Earth        3.839          7.91      2.06   0.9519 x radius
   Mars         1.351        0.7186     0.532   1.2480 x radius
   Jupiter      0.062         12.32       198   0.3821 x radius
   Saturn       0.014          1.96       144   0.4073 x radius
   ephemeris (EPM2017) formal limits on any extra perihelion motion: Mercury 0.008 mas/cy, Venus 0.315 mas/cy, Earth 0.033 mas/cy, Mars 0.003 mas/cy, Jupiter 33.9 mas/cy, Saturn 0.067 mas/cy (realistic: x10-50)

4. Double pulsar J0737-3039A/B: neutron stars, radius ~12 km, mean density ~4e14 g/cc
   M_lattice/P = 5.21e-13; predicted periastron advance 1.21e-16 deg/yr; measured 16.899 deg/yr

5. Special relativity alone (Sommerfeld 1916, same calculation as hydrogen fine structure)
   Mercury: GR 6 pi GM/(c^2 p) per orbit; relativistic mass alone gives pi GM/(c^2 p) -> 7.16"/cy of the 42.98"/cy
