Re: The semi-hollow moon

The moon rang like a gong because it's solid.

They expected it to ring twice with two different frequencies, like
the Earth, because they'd assumed it to have a separate mantle and
core like the Earth.

If it were hollow, it would have rung many times with the same
frequency, like a waterbed sloshing, due to the travelling wave being
trapped in a narrow band.

The 22-25 mile depth was the refraction depth due to the distance
betweem the crash and the detector. That doesn't mean there was
nothing below it, it just means the rocks bent the sound so that it
reflected back to the surface after this depth. This happens on the
Earth too. It's how we know how deep an earthquake occurred.


On Fri, 27 Feb 2004 15:56:40 -0600 (CST), WF11@webtv.net (߃-- ��)
wrote:

} When the Lunar Module ascent stage of Apollo 12 was sent crashing into
} the Moon, the seismological equipment recorded the shock waves.  The
} results staggered NASA scientists.  The artificially created Moonquake
} lasted 55 minutes!" 
}   "Furthermore, the KIND of signals recorded by the seismometers shocked
} scientists.  Seismologists were puzzled that the signals started with
} small waves, gained in size to a peak, and lasted for unbelievably long
} periods of time.  'The records are utterly different from any obtainable
} observations on the Earth,' relates one scientist in the highly regarded
} publication 'Science' (November 12, 1971." 
}   "The seismic records of Apollo 12 proved not to be unique.  When the
} spent 3rd stage of the ill-fated Saturn rocket booster of Apollo 13 was
} propelled out of Earth orbit into a Moon trajectory, and by radio
} command crashed into the Moon, it hit with an impact equal to 11 tons of
} TNT, about 87 miles from the site where the Apollo 12 astronauts set up
} seismometers." 
}   "The entire Moon vibrated for more than 3 hours, 20 minutes; the
} vibrations traveling to a depth of 22-25 miles." 
}   "The Apollo 14's S-IVB was also boosted into a Moon course and, by
} remote control, crashed into the lunar surface.  
} 
} 
} A NASA science publication ('Apollo 
} 14:  Science at Fra Mauro, p.17') said:  'The Moon reacted like a gong.
} For about 3 hours it vibrated and these vibrations traveled to a depth
} of 22-25 miles.' The instruments, by the way, picked up the vibrations
} even though they were 108 miles away from the Apollo 14 imapct site."
} ߃--��