🚀 go-pugleaf

On Mon, 10 Sep 2001 17:30:06 GMT, russotto@wanda.pond.com (Matthew
Russotto) wrote:

>In article <3B9BA470.F5323246@clark.net>,
>Tiny Human Ferret  <klaatu@clark.net> wrote:
>>Fabrikant wrote:
>>> 
>>> She also claimed that right after the collision, the Earth spin was so
>>> fast, that one revolution took 5 hours instead of 24.  The moon was
>>> originally much closer to Earth, and the distance is increasing by 3
>>> cm. per year.  The reporter, regretfully, did not know what question
>>> to ask.  Here are some questions, which I would like to ask.  First,
>>> how can she measure the distance between the Earth and the Moon with
>>> the accuracy of 3 cm? 
>>
>>Laser light reflection from some reflectors conveniently left up there for
>>just this purpose about 30 years ago. Light travels at a known speed, time
>>of flight calculations reveal distance. Same principle as radar, more or
>>less. 
>
>Those who went to the University of Maryland, College Park, may
>remember the laser on a building near the Computer Science Center,
>which was often fired at the moon.  If a print job never turned up,
>perhaps it was sent to the "Moonwriter."

Sounds like tedious work. Though it is amazing when you think about it
that the surface of the Moon accurately reflects the center of gravity
to within 3 cm. How can we determine the center of gravity of the
Earth with that accuracy? Guess we'll have to put a station on the
Moon to bombard a mirror on the surface of the earth, if we can find
an average place to call the surface of the Earth. Also that damn
fluid core may shift slightly from time to time. Buzzard's luck, I
just remembered molecules, atoms, ions, etc. are escaping from the
surface of atmosphere into space continuously. I wonder if they are
precisely replaced by the influx from the good old Sun?