(a) neil a. armstrong was the first person to walk on the moon. the distance between the earth and the moon is 3.85 × 108 m. find the time it took for his voice to reach the earth via radio waves. (b) someday a person will walk on mars, which is 5.60 × 1010 m from the earth at the point of closest approach. determine the minimum time that will be required for a message from mars to reach the earth via radio waves.