Question

Someday a person will walk on Mars, which is 5.6 x 10¹⁰ m from the earth at the closest approach. Determine the minimum time that will be required for a message from Mars to reach the earth via radio waves.

Answer 1

$t=\frac{2s}c,$

$t=\frac{2\cdot 5.6\cdot 10^{10}}{3\cdot 10^8}=18.7^m.$