The morning news. [volume] (Savannah, Ga.) 1887-1900, 1892-12-11
ORIGIN OF METEORITES.
WERE THEY THROWN FROM ONCE
ACTIVE LUNAR VOLCANOES,

the Requisite Power 70 Hurl Such
Bodice Within the Sphere of the
Earth's Attrsction-Thsy Travel for
Ages.
In the current number Of astronomy
and Astro. Physics, Prof. George W. Coax
Icy Of the University Of the City of New
York has an interesting article on the
probable Origin of Meteorites." Prof
Coakley defines the word meteorites, as he
uses 1t, "to denote only those solid masses Of
metals or minerals which have been ascer-
tanned to have fallen upon the earth from
some source beyond it," and he particu-
larry excludes shooting stars or showers Of
such stars.
Quoting various wri ters who have main
tanned that meteorites are Of volcanic orr
gin. Prof. Coakley disputes the theory that
she volcanoes from which the meteorites
were originally hugled were on the earth,
and then proposes theory which, be says,
10 neither his own nor new. IL is simply
that these volcanoes ''existed formerly in
an active state on our moon, and they alone
had the requisite power to throw these solid
bodies (meteorites) beyond the reach OF the
moons prevailing attraction and within the
controlling attraction of the earth"
space is established where the attraction Of
the moon and the earth urseQualized. Prof.
Coakley says:
"The velocity with which lunar volcano
nearest the earth must project body to
Just reach the nearest point of the sphere OF
equal attraction, at the distance from the
moons center equal to 23, 1884 miles is found
90 be / .443 miles per second. The velocity
with which the body must be projected
from a lunar volcano farthest from the
earth on the opposite hemisphere Of the
moon, to a distance from her center equal
TO y. S55 miles lie found 70 be l. $50 miles per
second. But while the projectile In the
former case, thrown toward the earth is
leaving the moons surface and drawn back
by her attraction, its flight is being helped
by theearth's attraction which alone would
impart TO IL final velocity at the surface
OF the sphere, equal TO O 292 mile per Sec
ond.
Hence the lunar volcano nearest the
earth needs only to impRrt the velocity 1443
minus 0.292 equals 151 miles per second in
order TO cause the proiectile to reach the
surface OF equal attraction. This 10 only
about three times the maximum velocity of
1000 feet per second Of a cannon ball In
the opposite direction, however, when the
projectile is launched from a volcano on the
moons farthest hemisphere. if there be- any
there, with the velocity 1.450 miles per sec
ond, the earth's attraction helI Q the moon to
SrinR II back with a total impaired velocity
OF O.292 miles per second. Hence the vols
cano ought to tmpart a velocity OF 1.450
plus Q. 800 equals .742 miles per second in or
der that the body may just reach the sphere
OF equal attraction. The velocity is only
about four and half times the cannon
balls maximum velocity of 1900 feet per
second. However, it is not improbable that,
IN this last case the earths attraction would
Neln the mO0n hrinO haCk tina nrOiAO4Jla
TO her surface. Though 10 Is probable that
the moons farthest hemisphere has been
subject TO volcanic action, like the hemi-
sphere nearest to us, yet we know nothing
certain with regard to that distant hemi-
spAere. We shall not count on IL In any way
In the theory Of meteorites, except that il is
now certain that an initial velocity of from
three to about four and half times the
maximum velocity Of cannon ball applied
In vertical direction to O projectile at any
point OF the moons surface would bring il
TO the surface OF the sphere Of equal attrac-
ton between the earth and moon.
Indeed, we may leave out OF account
any lunar volcano situated moro than $40
on great circle across he moons disk from
the point nearest the earth. In this case
every projectile from any volcano within
these 6ss Will be more or less assisted, In
lis flight from the moons surface, by the
earth's attraction The extreme velocity
which the volcano alone must supply to the
pro1ectlle will then be just about four times
the cannon bs!.J maximum velocity; aud
the least velocity required from the volcano
will be three times this maximum velocity
OF the cannon ball. Hence we have the fact
that over wide range of 1862 on O great
circle or the moons nearest hemisphere, in
every direction from 1ts visible center a
lunar volcano needs only to impart these
moderate velocities. Of three or four times
hat Of k.u \
the surface OF the sphere Of equal attraction
between the earth and moon
Every astronomer knows that the moons
nearest hemisphere is almost covered, in all
directions, by the craters of extinct vol.
canoes, many of them far greater In extent
than any on the earth. IL can hardly te
doubted that the earths volcanoes are
capable OF imparting, in a vertical di-
rection. a velocity three, four or five times
shat OF the cannon balls maximum. Hence
these larger lunar volcanoes must be con-
sidered capable of exertinR ct least an
equal force. The bodies protected from
them wouldireach the surface Of the sphere
OF equal attraction with various velocities,
and from all directions within 80 Of the
moons visible center, on a great circle
OF her disk. If the greater part of these
projectilee had fallen back to tine moon, the
interior floor OF her volcanic craters would
presenta very different appearance from
that observed. They would be filled up
with these irregular fragments, instead Of
presenting usually deeply excavated and
smooth surface, only broken occasionally by
q few small volcanic cones, the effects
probably OF subsequent minor eruptions
THE moons volcanoes must have been
active for many ages, though they have
now been extinct perhaps for millions Of
years. The explosions, which may have
sent forth the masses that have fallen on the
earth, should be considered as having taken
place at various periods, after long interval
from the same volcano. aud also &C different
times and in various directions, from other
volcanoes with different situation on the
moons surface. The projectiles should moi
be considered as all starting at once from
all the volcanoes, but their objection.
should be regarded as spread over long in.
tervals of time, whether from the same or
from different lunar volcanoes
Let US consider more particularly the
probable course of some one projectile
thrown from the visible center of the moons
disc directly toward the earth, and with
just sufficient velocity TO cause it to reach
the nearest surface Of she sphere of equal
attraction. What would happen when the
projectle reached this point? IL certainly
would not go back to the moon, because
the earth's equal attraction would prevent
such a result Neither would it go directly
10 the Qarfh haCansa ~ he ,~,oo1f. o,...g -