deletions | additions       diff --git a/The Earth.tex b/The Earth.tex  index 67fb025..ede8c13 100644  --- a/The Earth.tex  +++ b/The Earth.tex 
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\label{cearth}  C_\oplus = 8 D_{\rm US} &=& 2\pi R_\oplus \nonumber \\  R_\oplus &=& \frac{8 D_{\rm US}}{2 \pi}  \end{eqnarry} \end{eqnarray}  \item {\it What is the mass of the Earth?}