Improved test of the equivalence principle for gravitational self-energy

The lunar-ranging test of the equivalence principle for gravitational self- energy is ambiguous. Although the Earth has more gravitational self-energy than the Moon, its sizable Fe/Ni core also gives it a different composition than the Moon. We removed: this ambiguity by comparing, in effect, the acc elerations of "miniature" earths and moons toward the Sun. Our composition- dependent Earth-Moon acceleration, Delta a(CD)/a(s) = (+0.1 +/- 2.7 +/- 1.7 ) X 10(-13), and lunar-ranging data provide an unambiguous test at the 1.3 X 10(-3) level.