In the 1970's, I believe, the orbit of the moon was measured and found
to be expanding 3.8 centimeters per year. I need to who made the
measurement and where the data was published. Where is a reference to this data

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Request for Question Clarification by pinkfreud-ga on 24 Feb 2005 18:33 PST

Is this the project to which you refer?

"The Laser Ranging Retroreflector experiment was deployed on Apollo
11, 14, and 15. It consists of a series of corner-cube reflectors,
which are a special type of mirror with the property of always
reflecting an incoming light beam back in the direction it came from.
A similar device was also included on the Soviet Union's Lunakhod 2
spacecraft. These reflectors can be illuminated by laser beams aimed
through large telescopes on Earth. The reflected laser beam is also
observed with the telescope, providing a measurement of the round-trip
distance between Earth and the Moon...
 
The Laser Ranging Retroreflector experiment has produced many
important measurements. These include an improved knowledge of the
Moon's orbit and the rate at which the Moon is receding from Earth
(currently 3.8 centimeters per year) and of variations in the rotation
of the Moon."

http://www.lpi.usra.edu/expmoon/Apollo15/A15_Experiments_LRRR.html

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Clarification of Question by generaitor-ga on 25 Feb 2005 09:23 PST

Information is exactly what I was looking for. Need to reference
journal etc. where results where published

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Request for Question Clarification by pafalafa-ga on 25 Feb 2005 09:56 PST

Although not the ORIGINAL publication, the work of the LRRR, as it is
known, is described in this article, which probably includes the
original reference ('fraid I don't have access to the article at the
moment to check the references, though):


An unsung legacy of the first lunar landing 
Morrison, David C. 
Science v. 246 (October 27 1989) p. 447-8 

During their historic moonwalk on July 20, 1969, the Apollo 11
astronauts left behind a small laser retroreflector that has provided
20 years of extraordinarily precise data. The device, an 18-inch
square aluminum panel with 100 fused silica "corner cubes" that
reflect photons of light back to their point of origin, has allowed
geophysicists to calculate the distance between the earth and the moon
to within 3 centimeters, has confirmed several predictions based on
Einstein's general theory of relativity, and has greatly expanded
knowledge of the moon's orbit, allowing scientists to analyze solar
eclipses as far back as 1400 B.C.



The Morrison article can probably serve as a reference, if needs be.


pafalafa-ga

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Clarification of Question by generaitor-ga on 25 Feb 2005 12:37 PST

Great learning more about the experiment but I very perplexed that an
original reference isn't readily available. I have contacted several
people who have referenced the data (3.8 cm)but none can cite an
original source.  Seems like data was taken at McDonald Observatory in
Texas and someone there should have published a paper with results.
Thanks again