Joel Duff
Quoted material:
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83. Moon Dust and Debris
If the moon were billions of years old, it should have
accumulated a thick layer of dust and debris from
meteoritic bombardment. Before instruments were placed on
the moon, some scientists were very
concerned that astronauts would sink into a sea of dust--
possibly a mile in thickness. a This did not
happen. Very little space dust and debris is on the moon.
In fact, after examining the rocks and dust
brought back from the moon, scientists learned that only
about 1/67th of the dust and debris came from
outer space. Recent measurements of the influx rate of
meteoritic material on the moon also do not support
an old moon. (For more details, see technical note on
Moon Dust .)
(NOTE BY JD: Give him credit, he does say "before instruments were placed
on the moon" rather than when the astronauts landed they were concerned.
This does show more sensitivity to the historical data, though I am unsure
where the 1-mile estimate really comes from but I do now see that Brown is
using an alternative theory that suggested that meteoritic bombardment
resulted in dust accumulation, this allows him to get around the "better"
data showing little cosmic dust influx.)
JD: Here is how the technical note begins:
How Much Dust and Meteoritic Debris Should the Moon
Have If It Is 4,600,000,000 Years Old?
In 1981, I had a conversation with Dr. Herbert A. Zook
of the U.S. National Aeronautics and Space
Administration (NASA). He had been intimately involved
in estimating the thickness of the dust layer on
the moon before the first Apollo moon landing. He also
helped analyze the lunar material brought back
from the moon. Of the many interesting things he told
me and sent me by mail, one is critical in
answering the above question.
NASA did not realize until the moon dust and rocks
were analyzed that only one part in 67 (or 1.5%) of
the debris on the moon came from outer space. The
rest was pulverized moon rock. In hindsight, this
makes perfect sense. Meteorites that strike the
moon travel about seven times faster than a
bullet-averaging 20 km/sec. When they strike the
moon, they are not slowed down by an atmosphere
(as on earth), because the moon has no atmosphere.
Therefore, the projectile, regardless of size,
instantaneously vaporizes and kicks up a cloud of
pulverized moon rock. 1 The vaporized meteorite
then condenses on the pulverized moon rocks. This
was determined by slicing moon rocks and finding
them coated by meteoritic material-material rich
in nickel. Uncoated moon rocks have practically no
nickel. In this way, NASA arrived at the factor
of 67. 2
(JD: The conclusion Brown reaches is:)
Several people have published attempts to answer
the question of this technical note.
Those efforts have usually (a) overlooked the
factor of 67 (b) failed to consider the
larger meteorites (m > 10 6 gm), and (c) ignored
the assumption that the influx rate
has always been what it is today.
(NOTE: (c) is a rather intersting comment!!)
Conclusion
The above calculations cast serious doubt on the
prevailing opinion that the meteoritic material and
craters on the moon accumulated over 4.6 billion
years. Several other explanations can also be
addressed.
Could there have been a steady rain of meteoritic
material over only 10,000 years? If the above
calculations are repeated, replacing the 4.6 x 10
9 years with 10,000 years in the calculation for N E and
k, the expected thickness of lunar regolith and soil
becomes about 23 meters. This number is also too
large, although not as much as the 315 meters calculated
above. Therefore, the steady rain of meteoritic
material idea is probably wrong, even over a shorter
time interval.
Could the bombardment of the moon have been an event
rather than a steady rain? If we calculate just
the material contributed by the 125 largest impacts,
assuming the impactors were meteorites ,
we find that the thickness of the lunar regolith and
soil should be
This is also too large.
This author's conclusion is that the impactors were
comets, not meteorites. Comets are large dirty
snowballs (or muddy icebergs). Their water content
would have vaporized and escaped the moon long
ago.
What was the source of so many comets? Probably it
was the "fountains of the great deep," which
would have expelled large volumes of muddy water into
elliptical solar orbits. The water would have
quickly frozen and become comets. Much more will be
said about this surprising proposal at a later
time.