The Washington times., 1919-02-09

by the obedience Of their projectile to the
laws Of planetary motion, which compelled
it, on arriving inside the sphere of the
moons gravitational control, to pursue for
ever an elliptical path around the moons
centre Of gravity. which path did not at
any point lie inside the lunar radius. They
got out of their difficulty very ingeniousIy
by attaching a powerful explosive to the
outside Of the proiectile. and firing it at
such a moment and in such way that the
slight impulse which it impaired to the
projectile sufficed to throw it once more
within the sphere of the earth's control,
whereupon they then descended to their
native planet like a meteorite. and fell.
with their projectile externally ablaze from
the heat of aerial friction. into the deep
waters of the Pacific Ocean.
From what has been said it is evident
that the adventures of a prOjectile sent
away from the earth with parabOic We
locity would be highly dramatic We have
seen that freedom from the earth would
not imply freedom from the sun. The
moon would be dangerous only if il lay
straight in the track so that a head-on col
lision could not be avoided. Venus could
not arrest it. for her gravitational force is
less than that of the earth, but Jupiter has
a force of gravity about GIG times as great
as the earth's. so that the wanderer would
have to keep we'll away from him if It
were to escape the fate of being captured
and added to his cortege Of satellites.
So, too. Saturn might catch it and throw
it into the spinning torrents Of meteorites
that constitute his mighty rings.
If it escaped all these dancers it would
become an imitation comet. travelling
around the sun in an orbit o. gre"ter or
less eccentricity in accordance with cir
cumstances. but it would he a tailless
comet, and consequently DECEASED to be-
gin with, since to have a tail. which ap-
PEARS to be its greatest distinction. a comet
must be not a single solid body like a pro-
jeCtile. but a mass Of clashirg particles
from which, under the influence Of the
suns electric forces. streams of luminous
haze are swept off to fall into train behind
the rushing head of the comet.
Il would, then, perhaps be better to liken
the prOjeCtile to a meteOTite. ard thus
considered it appears possible that il
might at some future time be deprived of
its hard-won independence and sent back
like an escaped convict to the earth. This
would be brought about through what as
trOnomers call perturbation which is a
change in the direction and the velocity
of the motion of a celestial body produced
by the disturbing attraction Of other bodies
near which it passes.
Comets are frequently disturbed and
PLAYED with in that way, especially by the
giant planet Jupiter, and there can be no
doubt that il is owing to gravitatiOnal per-
turbation that meteOrites, after wandering
for ages in space, at last, in hundreds Of
cases. are thrown into such directions OF
fight that Trey become entangled in the
net of the earths atmosphere. and thus
are brought ANONYMOUSLY down from
their celestial courses to adOrn a museum,
and give a professor a subject for a
graphic lecture or an intricate calculation.
The similarity OF meteOTites to our pro-
iectiIe would become absolute identical II
the theory that ages ago they were shot
out of mighty terrestrial volcanoes could
he established.