Is it hazy tonight or is the moon just dusty

Joel Duff (
Thu, 5 Nov 1998 21:40:15 -0500

I looked in several books today to try to assertain how much concern there
was about dust and to see if scientists were "astounded" not to find any.
Two book covering the results of the lunar program from the 60-70s had no
obvious reference to moon dust at all. I looked through several volumes of
Lunar Conference Proceedings detailing results of the lunar landing and
found nothing about dust beyond its compositions and some very dry
statistics about density, size, etc... One book "To a Rocky Moon; A
geologists History of Lunar Exploration" by Don E. Wilhelms devotes over
200 pages to pre-1969 geological investigations of the moon and concerns
for the moon landing. Despite the tantilizing title of the book, the moon
dust problem is discussed in only 4 paragraphs on 2 pages (at least that I
have found thus far). I thought the comments were interesting enough to
copy here.

Joel Duff

Quoted material from pgs 67 and 68.

"Meditations about the surface were tied to the impact-volcanic
controversy. If the craters were volcanic, as the hot-mooners thought,
then the surface material might be entirely volcanic as well--lava, ash, or
tuff (consolidated ash). If impacts created the craters, the bedrock could
be of any origin, but them impacts would create from it a suface layer of
rubble and dust. This was the view of Baldwin, who had concluded by 1949
that the surface is covered by "large quantities of dust or fine particles
spread over the ground." In 1959, after a thorough discussion of the
problem at the lunar colloquium in Dallas, the genaral opinion was that the
surface dust was pruduced mostly in place by micrometeoritie impact and
solar "emanations." The majority futher thought that the layer owas on the
order of a few meters thick. But voting does not establish the truth of a
scientific question. The impact debris might be ejected from the Moon as
fast as it formed, leaving bare volcanic lava or slag. At the opposite
extreme was Gold - he was always the extreme- who believed that the dust
layer was dangerouly week and hundreds or thousands of meters thick.
Neither he nor Gilvarry seemed to understand that lava could lie beneath
surface dust; to them the maria "were" dust.

Some other possibilities for the nature of the surficial material
provided wonderful diversions. One was expressed in what Baldwin in 1963
referred to as a "now famous" comment by biophysicist John R. Platt in 1958
that "the first man who plants a rubber boot on a lunar surface may be in
for an unpleasant surprise" because the surface may be covered by
interstellar dust that might react violently to the intrusion. Another was
that if impacts eject much fragmental debris and if many impacts are still
occurring,then the astronauts could be endangered by the flying particles.
One of the early cooperative efforts between the USGS and the NASA Ames
Research Center addressed this danger. Don Gault, Gene Shoemaker, and
Henry Moore concluded that considerable debris would be sprayed around on
today's Moon and might present a hazand if an astronaut stayed long enough.
They bowed to Gold by remarking that this cloud of particles was a good way
of producing his dust. But they correctly concluded that the amount of
debris generated greatly exceeded the incoming mass, and that enough would
sstay on the Moon to accumulate on the entire surface as a deposit of
poorly sorted debris.

As with our other topics, we can look back and find the wheat
admist the chaff. Baldwin and the USGS-Ames studies had the surface layer
about right, as did geologist and remote-sensing specialist John Salisbury,
who was at the Air Force Cambridge Research Laboratory between 1959 and
1976. A perception that is close to today's appeared in a 1964 book edited
by Salisbury and this colleague Peter Glaser, with a preface by Baldwin,
that constituted the proceedings of a 1963 conference on the surface layer.
The voting had decided that the entire lunar surface is covered by a
deposit with variable thickness consisting of mixed, unsorted impact debris
ranging from microscopic particles to large blocks. So it is; but the
effort to prove it continued for several more years. "
end quote