Evening star., 1934-11-28
MOON MOUNTAINS
STUDIED BY LIGHT
Surface Is Almost White in
Appearance, Scientists
Believe.
BY THOMAS r. HENRY.

KY IHOMAS
The mountains of the moon, some
Of them almost as high as Mount
Everest, are being studied by means
of the moonlight from their surfaces.
A report on the progress of the Car
negie Institutions committee on the
surface features of the moon was pre-
sented last night by DR.. F. E. Wright
Of the geophysical laboratory, chair
man of the committee, at the lnstl-
tution's headquarters here.
Moonlight is being studied by some
of the most delicate instruments known
to modern science DR.. Wright said 1t
is reflected sunlight, since the moon
has no radiation Of its own. 1t re-
quires about a second and a quarter
to pass from the moon to the earth.
What happens to 1t, shown by its
difference from ordinary sunlight, on
the arid, airless surface of the earth's
satellite is compared to the effects OF
sunlight of reflection from various
mineral materials on earth.
One point of approach is the phe-
nomenon of polarization by which
some of the properties of light become
MllCll 1IlCo IA OPPOo4eS VA
rections. The committee has found
that light reflected from the moon is
very little polarized. approximately
the same effect is found on earth when
sunlight is reflected from light colored
rocks. thus establishing the fact that
the surface of the moon must be almost
white in appearance.
Volcanic Ash.
Additional evidence has been gath
cred that the surface materials must
be largely of the nature of volcanic ash
and pumice, high in silica. This has
been determined by the rate of cooling
of the moons surface during an
eclipse, from above the boiling point
of water to 100 degrees centigrade be-
low zero in the course of an hour.
This shows the surface materials must
be very good insulators. They can
not absorb much heat, as they would
if they were Of such materials as
granite or limestone.
There is no water, ice or protective
blanket of atmosphere to soften the
impact of the suns rays and prevent
the escape of heat radiated from the
moons surface" DR.. Wright said.
The inflow of the suns radiation
probably maintains temperature a
few feet below the lunar surface not
far from zero, centigrade, in spite of
the fact that the temperature of the
surface itself oscillates though a range
of several hundred degrees during each
lunation.
The craters of the moon are so
vast the terrestrial craters are insig-
niflcant in comparison. The mountain
GUS areas are quite unlike terrestrial
mountains and, for the geologist, very
difficult to interpret. They reach
heights of $4,000 feet in isolated cases,
while the deepest crater has depth
OF about $4,000 feet. The lunar noun
famous areas are also extremely rough
and would be very difficult to traverse,
even if there were water and air pres
ent to support life.
Absence of Water.
"From a geological viewpoint, the
absence Of water and air on the moon,
coupled with its low gravity pull, are
factors favorable for the DEVELOPMENT
of extremes in surface forms. AS a
result OF low gravity and the lack of
air resistance, the rajectories of ma
ter1als thrown out of craters are from
so to 100 times longer than the trajec-
tories OF the same materials evicted at
the same initial velocity and elevation
angle on the earth. The materials eject
ed from lunar crater are scattered
wide, whereas on earth the greater part
of fha q foil hoo l. i,,fo
the crater mouth and on the nearby
surface. AS result, the lunar craters
are cleaned out as a rule and are of the
nature of deep holes in the ground
with the floor Of the crater below the
level of the surrounding country"
Besides the study of its polarization,
DR.. Wright said, studies of moonlight
are being made by three other
methods-the photo-electric cell, the
thermoelement and the polarization
spectrograph-but they have not
reached the point where any results
can be stated. The committee is max
ing an effort to determine the exact
distribution of energies in the spectrum
on moonlight and the changes that
take place with different phases of the
satellite. Much attention, he said, is
being given to the preparation of a
good lunar map.
He exhibited four miniature moons
prepared by projecting negatives of
the moon, taken at different phases,
on large glass globes coated with pho
tographic emulsion. This is the first
time that a globe has been used as a
Photographic negative, and represents
a new advance in Photographic tech
nique.