Indiana daily times., 1921-04-11
LIGHT-SPACE
CURVATURE SET
OUT IN THEORY
Einstein Makes Contribution
: to Fundamental Laws
of Science.
POINTS DISCUSSED
BY GERRIT P. SERVIsS.
written for and copyrighted 1921 by
International News Service)

written for and copyrighted l921 Dy
International News Service)
NEW YORK, April 11.-Thanks to the
presence in this country of Albert Elm
stein, have just had an opportunity in
the course Of a social conversation with
him, to obtain somewhat clearer ideas
concerning the most puZzhng points in
the application of his great theory OF
relativity to the fundamental laws OF
modern science.
There are three chief points of the
Einstein theory which stand out con-
spicuously and to the average reader
seem to be rather stumbling blocks than
aids to comprehension and these l tried
ITO have cleared up.
They are:
First, that absolute motion has no ex-
istence so far as We are concerned, but
that all motions of every kind that we
see or of which we perceive the effects
are only relative TO one another and can
be measured in a relative sense. In
other words, we have no liked back-
ground to which all motions alike can
be referred Until recently it was
thought that by refined observation 1t
should be possible to detect the effect Of
the earth's motion through the ether Of
space, The failure OF the most elaborate
attempts to detect such motion was the
beginning of Einstein's discovery of the
principle of the relativity of motion.
This, put in a sentence, means that no
uniform motion relative to the ether can
be detected.
SURROUNDED
BY PROOFS.
We are surrounded every day By
proofs of relativity that We ordinarily
do not notice When a railway train
standing beside our own in station
starts to move sometimes we can
scarcely persuade ourselves that 1t is
not our own train that is in motion.
This is a perfect example Of what Is
meant by relativity Of motion. 1t be-
comes more complicated but not less
clear, when we apply it to the motion
of the earth, around the sun, combined
with the motion of the sun together with
all its planets through space and the
probable motion of the entire system of
the stars as we see them, in complicated
directions There is no one background
or pIane of reference which ena bles US
to detect the absolute motion in any or
these cases.
Second. the next stumbling block is
the statement that ray of light coming
from a distant star and passing close to
the sun on its way to the earth is bent
or deviated from its course just as If
the light consisted of something having
weight.
Third, another pulling point is the
conception growing out of the Einstein
theories that space does not extend uni
formly in every direction independently
of the bodies. such as planets, suns and
stars that it contains, but that space
in itself has what one might call kind
Of shape, more specifically, that it
possesses curvature, and that what seems
TO US straight line, may, if followed
far enough, turn out, or perhaps
necessarily must turn out to be a curve.
TIME SPACE
DIMENSION.
Fourth, still another thing in the Elm
stein theory which is difficult for the
general reader to grasp, is the idea that
We call time. in a sense, a fourth dimen-
sion of space, and that space and time,
instead of being, as has generally been
assumed by scientific men, heretofore,
entirely separate and independent things,
are essentially connected.
It was the hope Of obtaining, with
Professor Einstein's aid, a clearer state
ment of the meaning and relations Of
these various points in his theory that,
being fortunately thrown into his com
pany, 1 took the liberty OF questioning
him
In regard to the first point. the state
ment already made above may stand as
representing about as clear presenta-
:. tion of the matter as can be put in few
words. Its relation to the points can be
developed as We go along. In fact, 1t
comes out Immediately in the explana-
tion Of why a ray OF a star is deviated
by the attraction OF the sun. This is due
to the curvature OF space in the neigh
borhood Of a heavy, attracting body such
as the sun. At great distance from an
attracting body space may be essentially
straight, but in the immediate neighbOr-
hood of a body 1t assumes curvature
This IS a result of calculations which
those who are not familiar with the
higher processes Of mathmatics. 1t in
wolves the idea Of the essential relation
of time to space. 1t is in what is called
space time," or time space" that this
curvature is produced, and 1t is the re-
suit Of motion.
LIGHT RAY BENT
OUT OF COURSE
Now, IL a ray of light from a star away
of in space, billions of miles beyond
the sun, passes close to the suns sur
face, where space is comparatively
curved, or where its curvature becomes
distinctly manifest, the result is that
that ray following, so to speak. the curva
ture Of space through which it passes is
bent out of the course that 1t formerly
pursued, Just as if sun had attracted 1t.
The direction of the bending or curv
ing of the ray is toward the sun and
when the ray, having been thus detected,