The herald., 1895-08-08
Many Theories Are Held
About 1t, But Who
Is Right?
WHAT LAPLACE THOUGHT
The Writer Holds That the Nebular
Hypothesis Deserves to Be Raised
to the Rank of Q
Theory
Dy DR.. w. n. nasseh

Today the term evolution" brings to
almost every mind train of thought le-
lating to the origin and development OF
man. But the scientist has exetended
the use of this term to the explanation of
the oruigin of many things and IN this
genera. sense the evolvement of solar and
planetary systems is included.
How the world in particular the sun,
the planets and the stars came into exist
ence is discussed by almost all forms of
religion and by almost all the ancient
forms of philosophy. About one hun.
dred years ago the celebrated astronomer
and mathematician, Laplace. attacked the
problem anew and propounued the now
we'll known nebular hypothesis. Chemis-
try being then in its infancy and the sew
eral ethers which were invented to ex.
plain several phenomena, hardly being
considered forms OF matter, his specuia-
tions to what was the basic substance
out of which worlds are formed, were
almost of necessity restricted to the fire
mist of the alchemsts.
While his hypothesis accounting for
the origin of the solar system has never
been demonstrated by observation, or
esta bli shed by mathematics, neither has it
been disproved. Its boldness and reason
ableness give 1t fascination and digni-
tv not exceeded by the Kinetc theory of
gases. be.corroborative evidence deriv-
ed from the study of our solar system in
particular and in smaller degree from
stellar systems and thernebulae, causes
astronomers to regard it on the whole
with considerable approval. The late OBJ
servations or Professor Pickering on the
moons of Jupiter seem to explain the
cause of the retrosrade movement of the
moons of Uranus, the greatest objection
ruised against the hypothesis. But If the
existence of the star dust" the world
stuff" the nebular mist, can be establish.
ed. and it can be identified as established
as condition oflmatter, the fundamental
speculations of Laplace lose the chaIac-
ter of pure hypothesuis His concep'
tion then becomes physical theory,
which in proportion as 1t is verified by
law of cosmic evolution. If this can be
done, the scope of Laplace's hypothesis
must necessarily be largely extended.
Then if :he modified hypothesis explains
the augmented list of phenomena as well
or even better than it did the smaller
list, it must receive attention.
Luplace supposed that the sun was for
merly very much larger than it is at
present. and presumably in the gaseous
condition; also, that IT was surrounded |
by very tenuous or nebulous atmosphere |
that extended somewhat beyond the orbit
mass of nebulous vapor acquired rotary
motion in the direction IN which the ,
planets now move around the sun,
through its cooling and condensation.
Then, after ,rtain amount of condensa-
ton, the centrifugal motion of the outer
equatorial part would more than counter |
balance the attraction to the center. AS |
a result, a ring of nebulous matter would |
separate and would then revOlve around |
and in the equator of the inner mass and |
in the same direction. A continuation |
of the process Of condensation would re-
suit in other rings lying inside thetirst
and revolving in the same direction, but |
with different velocity. A lack of uni. |
formity OF density of the nebulous mass |
or uniformity in its condensation would |
cause the amount of matter thrown off in |
the rings to be unequal. That the same |
lack of uniformity in the density and in |
the further condensation of the nebulous
matter of the rings would cause them to
break and roll themselves up into gas
eous spheie-a future planet. That this
gaseous planet would of itself, by a con-
tinration of the same process. form rings
which would afterwards become satellites.
According to this beautiful conception of
Laplace, the formation of the planets of
our solar system, all being OF different
size and having different velocities OF
motion, but. all moving in nearly the
same plane OF the ellip ptic, is readily ac-
counted tor. The central part of the neb-
ulous mass left after the formation of the
last ring is the origin of the sun. AS an
actual example of the fultillment of the
nebular hypothesis. Herschell directed
attention to many nebulae which
were evidently in the process of acquiring
spherical form, and commencing to
consolidate preparatory to throwing off
rings. Prof. J. Homan Lockyear has
somewhat modified the nebular hypothe-
sis of Laplace. 1t is known as the me
teoric theory
Prof. |. N.Vail of Pasadena in his