The San Francisco call., 1909-11-28


The moon. were in reality but the
bumps" made by impact with smaller
satellites or flying meteors. was the
statement by which Prof. T. J. J. See,
director of the United States naval OBJ
servatory at Mare island. explained to
The Astronomical Society of the Pacific
his theory in regard 10 the cavities in
the moons surface.
Since astronomy has been far enough
advanced 20 recognize the existence of
these cavities it has been supposed that
the queer holes in Luna were volca-
noes, but the explanation given by Pro-
fessor See not only revolutionizes that
idea but can be applied TO the obliquity
or planets with the result that he
overcomes the last difficulty in the way
Of the capture theory" which has re-
Gently supplanted the old nebular hy-
pothesis OF Laplace.
LECTURE AT OBSERVATORY
The lecture was delivered by Profes-
sor See at the students observatory.
University OF California. Prof. Heber
ID. Curtis Of Lick observatory also
spoke on the work Of the ID. o. Mills
expedition. Dr. See was introduced by
". W. Campbell, president of the So
ciety, and began with his paper on the
moons craters. explaining the result of
The researches OF which he gave a short
account in January and June of the
present year
Professor See announced that the
lunar craters were due to the impact of
smaller satellites against the surface
of the moon, and not to volcanic ac-
tion. as had been generally believed
since the time Of Calico. The view that
the lunar craters might be due to i'm
pact. ne said had occurred to Proctor
as long ago as 1873, and had been men
toned as q curiosity by Newcomb in
1873. while il had been more fully de-
Neloped by Dr. q. K. Gilbert of the
United States geological survey in 1892
But the impact theory had never been
accepted by biologists or astronomers,
and was not mentioned in any recent
works on astronomy. so great has been
The force Of traditional opinion inclin-
ing TO the old volcanic theory.
VOLCANO THEORY EXPLODED
Professor See. however, pointed out
detailed reasons which were decisive
against the volcanic theory, and re-
marked that there would now be less
difficulty in seeing the truth of the /
impact theory. because he had recently 1
proved that the moon was not part 4
OF the earth thrown of by rapid rota- i
tion, but planet captured from space i
The new theory OF the capture of the I
moon. he said had been favorably re-
ceived by the scientific world, but 1t
would be of still greater use in bring /
ing TO light other discoveries.
Doctor See said that the typical
crater on the moon was very large (
circular depression with steep walls
inside and sloping walls outside and a
small peak in the center. with the top /
law al of he
lunar service. II any one supposed the
craters to be volcanic it was impossible
to account for the depressions where /
the craters stand, and no forces direct 4
ed from within could dig out the cir
cular trough about the peak In the /.
center Then. too the way the craters {
lie over one another shows that they
are nothing but satellite lndentations.
About the newer craters, as Copernicus,
Tycho. Aristarchus. etc, the bright
rays radiating in all directions show
that at the time of the collisions the
force Of the impact was such that
matter was melted, vaporized and
driven out from these centers in all
directions. A satellite hitting the
moon might have its temperature
raised TO 1000 degrees or higher. and
the bright rays from the crater were
due TO the spattering of highly heated
matter.
SATELLITES HURLED AT MOON
The blazing flash seen in target prac-
tice when a shot hits the target was
familiar to officers of the military ser
vice. said Professor See. and the fat
tening and spreading Of the projectile
was such as TO give peak in the
center of the mashed shell while at
the same time a rim is formed around
il. Just ike that seen about the craters
on the moon. But the shot fired in the
mghtiest target practice on the earth
IS as nothing compared TO that in the
heavens, where satellites from 20 TO
50 miles in diameter had been hurled
a gainst the lunar surface with We
locity Of over a mile a second. and
thus produced blazing conflagrations
sometimes covering the whole side of
the moon.
Professor See pointed out that many
of the craters were covered with cos
mical dust, a kind Of metallic or lithic
rain which had fallen from such con-
hagrations. He said there was no air
about the moon in which it could long
suspended.
HARD KNOCKS FOR PLANET
Professor See said that the moon
never had had any seas or smaller
bodies Of water. but the lunar noun
tains were entirely due to impact of
against the surface He
thought that most Of the great col
lisions had occurred before the moon
was captured by the earth, and there
fore while the moon was still revolv-
ing in the region now occupied by the
asteroids. The smaller asteroids. he
said. are about the size Of the falling
bodies which have produced the larger
lunar craters-from 40 to so miles
across. This is about the size of the
planet Eros, which approaches nearer
the earth than any other known planet
The roughness of the surface of our
moon shows how many hard knocks it
has received in the past. Every planet
has gone through q similar expert
ence, but those having atmosphere and
oceans, like the earth, have suffered
such great geological changes that
they have long since lost all trace of
ancient battering. while these indenta-
tions have survived on the airless and
moon. 10 show us the ter
rife process by which worlds are
formed" declared Professor See
OF PLANETS
In a second paper presented tonight
Doctor See explained the obliquities of
the planets by the impact of satellites
against their surfaces. He said he had
discovered the cause of the oblioufties