Saturday, July 4, 2015

Retro Saturday: A New Look at the Old Moon


Click the arrow to watch the film. Video source: wdtvlive42 YouTube channel.

Want to prove the Moon landings weren't fake?

Then watch this 1979 documentary.

A New Look at the Old Moon was produced by NASA for the tenth anniversary of the Apollo 11 landing.

The film somewhat disingenuously suggests that the Apollo program was all about geological research, when in reality it was about prestige, to prove that U.S. technology was superior to the Soviet Union.

Mild propaganda aside, the film reminds us that, once the astronauts landed, they left behind automated science stations that for years transmitted data.

Apollo 11 left behind a lunar laser ranging retroreflector array. According to this 2004 NASA article:

University of Maryland physics professor Carroll Alley was the project's principal investigator during the Apollo years, and he follows its progress today. “Using these mirrors,” explains Alley, “we can 'ping' the moon with laser pulses and measure the Earth-moon distance very precisely. This is a wonderful way to learn about the moon's orbit and to test theories of gravity.”

Here's how it works: A laser pulse shoots out of a telescope on Earth, crosses the Earth-moon divide, and hits the array. Because the mirrors are “corner-cube reflectors,” they send the pulse straight back where it came from. "It's like hitting a ball into the corner of a squash court," explains Alley. Back on Earth, telescopes intercept the returning pulse — “usually just a single photon,” he marvels.


The Apollo 11 lunar laser ranging retroreflector array. Image source: NASA.

To this day, the University of Texas McDonald Observatory operates the McDonald Laser Ranging Station near Ft. Davis, Texas to “ping” the Moon.

Ask the next conspiracy nut you encounter how it is we shine a laser beam off the Moon if someone didn't place a mirror there to reflect the beam.

The Apollo 11 reflector was the basis for a scene in the third-season episode of The Big Bang Theory titled “The Lunar Excitation.”


Click the arrow to watch the scene from “The Big Bang Theory.” Video source: Dshuann YouTube channel.

Other data were transmitted back from the Apollo missions as part of the Apollo Lunar Surface Experiment Package (ALSEP) program. Five ALSEP stations were left on the Moon. The stations were shut down in 1977.

Click here for the Lunar and Planetary Institute archive of ALSEP experiment results.

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