1. The problem statement, all variables and given/known data The Apollo 11 astronauts set up a panel of efficient corner–cube retroreflectors on the Moon's surface (see figure below). The speed of light can be found by measuring the time interval required for a laser beam to travel from the Earth, reflect from the panel, and return to the Earth. Assume this interval is measured to be 2.51 s at a station where the Moon is at the zenith and take the center–to–center distance from the Earth to the Moon to be equal to 3.84 108 m. (The Moon's radius is 1.74 106 m, and the Earth's radius is 6.37 106 m.) (a) What is the measured speed of light? (b) Explain whether it is necessary to consider the sizes of the Earth and the Moon in your calculation. 2. Relevant equations 3. The attempt at a solution Why the measured speed of light is not equal to 2d/t?And I don't know why the size of the earth and the moon need to be taken into account? THANKS!!