Answer
$6.6$
Work Step by Step
We can find the required ratio as
$\frac{I_M}{I_E}=\frac{P_{Sun}/4\pi r^2_M}{P_{Sun}/4\pi r_E^2}$
This simplifies to:
$\frac{I_M}{I_E}=(\frac{r_E}{r_M})^2$
We plug in the known values to obtain:
$\frac{I_M}{I_E}=(\frac{1}{0.39})^2=6.6$
