## Weber versus Weber: Why the Electrodynamic-Gravitational Analogy Breaks Down

We read from Forward, in "Guidelines to Antigravity", that (Joseph) Weber used Einstein's theory to determine the acceleration of a small mass $m$ by a big mass $M$. The resulting force was found by Weber to be given by

$$ \vec{F}/m=-\frac{GM}{r^2}\left(1+\frac{\vec{v}\cdot\hat{r}}{c}\right)\hat{r}+\frac{4GM}{c^2r}\left(\vec{a}+\frac{\vec{v}\cdot\hat{r}}{c}\vec{a}+\frac{\vec{a}\cdot\hat{r}}{c}\vec{v}\right),$$