Evening star., 1909-03-07
MOON AND EARTHPART
Distance Between the Two
Gradually Increasing.
JOINED TOGETHER ONCE
Sir George Darwin Tells of Theories
of Scientists.
TIDES OF TERRESTRIAL GLOBE
Movements Correspond to Those Of
the Ocean-Sensational An
nouncement by Flammarion.

Special Correspondence Of the New York Sun.
LONDON. February "a. 1909.
Camille Flammarfon caused sensation
in Paris the other day by making what he
described as 1.-The almost incredible an
nouncement'' that 1t had been established
as the result Of recent observations that
the earth twice every day experiences gen.
eral undulations corresponding to the tides
of the ocean. This discovery. as already
cabled, Is due to the observations made
at the Potsdam observatory by the as
tronomer Hecker, who by means Of spe-
cial Instruments has ascertained that
the apparently solid earth is subject to
daily oscillations analogous to the tides.
rising and falling twice in every twenty
four hours some twenty centimeters, or
about eight inches The movements are
not noticeable any more than is the &C
ton of the tides to any one on board
ship at sea
Yield Of the Earth.
More than twenty-five years ago Sir
George Darwin and his brother Horace
Darwin. sons Of the great Charles Dar-
win, together made an elaborate series
of experiments with view to computing
the yield Of the earth to tidal forces.
They concluded that almost all the r,ove-
ments Of their very delicate pen j ium
which they could measure were que to
extraneOus causes such as minute earth
quakes and effects Of temperature and
pressure.
Sir George Darwin referred to these
experiments Of himself and his brother
in an address couched In popular Ian
guage given at the Authors Club last
Monday night
Earth and Moon Drifting Apart.
"In tidal notion" he said. 1.-The move
ment of the water is subject to friction
slight though 1t may be. This friction
acts as a very slow brake on the earth's
rotation. 1t Is almost infinitesimal in
amount, SO small that it has not been
measured, but yet 1t must exist
Acting always in one direction. the
earth must be slowly spinning slower
Further than this, as the friction is due
principally to the moon there must be a
reaction on the moon, and the effect of
that reaction Is to drive the moon further
and further from the earth. Given the
millions of years which we believe the
solar system to have existed, we can
trace the history Of the moon and earth
backward.
"If then we follow these changes back
ward. In time we reach an epoch when
the moon was only two or three thou
sands Of miles from the earth. You may
say that II this friction Of the tides is
driving the moon away from the earth
now, on going backward in time far
enough we must come to a time when the
moon was close to the earth. Such a
conclusion Is obvious, but the remarkable
fact about this result Is that 1t appears
that when the moon was close to the
earth 1t always faced the same side of the
earth.
Moon and Earth One Body.
Thus the two bodies moved around to-
gether as il they were linked together.
and the speed at which they spun around
was only three or four hours. This points
clearly to the idea that in very early
times the moon and earth were one body.
which spun 50 fast that 1t broke in two.
and that the smaller body. the moon.
was sent away to where we see 1t now
by tidal friction.
although the moon looks 50 big in the
sky 1t is small compared to the earth,
being only one-eightieth part as heavy.
Perhaps you think all this fanciful. and
Of reasoning which removes the theory
from the regions Of fancy. In any case
this view Is now very generally accepted
by men of science. and some have even
speculated as to what part of the earth
the moon broke away from.
1T has been suggested that the Pacific
ocean is the hole left by the moon. l
will not say that l accept this-I will
only say that l do not think we have any
proof of it.
Long Day of the Future.
Now if instead of looking backward
we look forward we shall find the earth
spinning slower and slower and the moon
going further and further, and at last
when the day Is hfty-five times as long
as 1t Is now the moon will again always
face the same side of the earth.
1T follows, then, that by reasoning
from which it Is impossible to escape we
may trace the moon from a time when
she was close to the earth TO a distant
future when she will be at an immense
distance from 1t, and we begin with
day of three or four of our present hours
and end with a day of f1fty-five of our
present days.
Although Sir George Darwin credits
DR.. Hecker with full success In measur-
ing the earth tide, and alis authority is
great, there Is still an inclination among
men of science to wait until Hecker's fig
ures have been thoroughly examined be-
fore accepting them completely. Many
experimenters have attempted the prob
success they have produced little evil
dence in support of their statements.
One of the points mentioned by Sir
George Darwin in a passage of the speech
quoted above is used to cast doubt upon
the. theory that earth movements, which
are undoubtedly accurately measured,
are really of a tidal nature. Sir George
points out that the constant tidal heap
ing Of the oceans against the shore must
produce a considerable earth movement,
and this might very we'll be mistaken for
an actual earth tide.