How Did They Measure The Approximate Distance From Earth To Moon?

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JAYESH KUMAR Profile
JAYESH KUMAR answered
We humans found the distance between the earth and the moon through a method called "the laser pulse method".in this method a strong laser beam is transmitted towards the moon. A sensitive receiver in the earth received the bounced signal.the total time was calculated and the distance  was determined by the formula "d( distance=v(velocity)/t(time).
here time is t/2 as the total time consists of the time to reach the moon and the laser beam coming back. So,time is divided by 2.is it enough?
thanked the writer.
Richard Enison
Richard Enison commented
Both of the answers (seems to me there used to be three) refer to the laser method, which is certainly the latest and most accurate method, but before there were lasers, the distance was determined using parallax (triangulation), with the diameter of the Earth as a base, and orbital mechanics (the period of the moon's orbit, about 28 days, gives a rough estimate of its distance from the Earth).

BTW in 1969, when my two apartment-mates and I were working for NASA, one of my apartment-mates was involved in the laser experiment, using corner-cube mirrors left on the moon by the Apollo 11 astronauts, which proved that the moon was hollow; it vibrated ("rang like a bell") for 30 minutes when the Lunar Excursion Module was dropped on it after the astronauts returned to the orbiting Command Module.
Anonymous Profile
Anonymous answered
They used special mirrors those could reflect back the laser back to earth to know the distance in picoseconds. For more info click here.

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