Omaha daily bee., 1916-03-06
By GARRETT p. sERvIss.

''Idndly explain what causes the earth
to rotate.-S. B. p"
OF course you mean to ask. what
started the earths rotation7 Once turn
ing, there is no difficulty in seeing that
it must continue to turn unless some
force interferes TO arrest its motion.
Science, at present, is unable to give
definite answer to this question. Per-
haps 1t never will be able TO give such
an answer. 1t is a part of the great
problem of the origin OF the earth and of
the whole solar system, which consists
of the sun: eight planets. including the
earth; some twenty-five or twenty-six
satellites, or moons. belonging to the
planets; hundreds OF planetoids; a large
number of comets. and many swarns
of meteors
All these things together make up
gigantic mechanism OF which the sun is
the motor. or governor. which keeps 1t
running. The entire system revoles round
and round the sun and each of the
planets rotates round its own axis, like
spinning ball. the direction, OF both the
general revolution Of the system and the
particular rotation OF the individual
planets being the same. with certain ex-
ceptions. which can be accounted for
as due to particular causes
Since all the motions within the solar
system are linked together and have a
certain concord. 1t Is to be inferred that
they must have had a common origin.
We may say, then, that the earth rotates
because a motion of rotation was i'm
pressed upon 1t when it came into exis"
lance, together with the other members
/
mon center the SUM and rotation around
their own axes are effects OF great
fundamental mechanical law controlling
all OF the planets.
The sun itself which exceeds in mass
OF quantity OF matter hundreds OF times
all the other members OF the system
combined. also obeys this law and ro-
tates on its axis in the direction In which
the planets revolve around It.
Whatever force set the entire system
into revolution was, no doubt the funda-
mental source OF all the revolutions and
rotations that we find among It's mem
bers That force acted when the system
was created. According 10 the general
belief OF astronomers the start was made
in a nebula. A nebula Is a cloud OF gases.
or perhaps a cloud OF dust or OF small
meteors. which is capable by condensa-
ton of being shaped into stars or suns.
The great French mathematician La
place invented a celebrated theory to
lexplain the origin OF the solar system
which is known as the Nebular Hypothe-
sis He supposed that there was once a
nebulous mass land the telescope and
photography show many such now in
the SKYE which, under the attraction OF
It's own particles for one another. con-
tracted and assumed a globulRr shape.
In consequence OF some lack OF balance
among the motions OF the particles in
the nebula the entire mass as Il con-
tracted got into rotation. somewhat as
the water In a vessel sets inseh into a
whirl when a stopcock is opened at the
bottom. Some irregularity in the flow
starts a motion In a particular direction.
and then all the water begins 20 move
that way
As the nebula continued to contract II
became more and more dense at the
center until a globular condemnation was
formed there which ultimately became
the sun At the same time the rotation
OF the entire nebula increased In velocity.
as the laws OF mechanics would require
q 20 do. as a result OF the shrinking
OF the mass. and then the centrifugal
forces flattened II out into the shape
OF a disk. When the rotation became still
swifter rings OF mattel began TO sepa-
rate off from the whirllns disk, and these
rings. when they broke. rolled them
selves up. 80 TO speak. into nebulous
balls. which ultimately condensed into
the earth and the other planets
The globes. or planets. thus formed
would rotate in consequence Of the orisi-