Evening star. [volume] (Washington, D.C.) 1854-1972, 1896-11-24
IT THE E#IH'S. CENTER
Opinions Differ a. u the Weight Of an Iron
i,.sspan.
Corre.pondents Who Do Not Agree a.
to whether 1t Would Stor-
.lI1i.
Reasons for Their Views.


Earths Center " seams to have developed
quite difference of opinion on the SUBJ
ject In the article credited to the st.
Louis Republic, which started the contro-
versy 1t was stated that II 1OO-pound
ball could be dropped into hole through
the center Of the earth it would come to
dead stop the moment 1t reached the
center.
"S. g. X" in the communication Friday
took exception to this view and held
that the ball wouldskeep moving from sur
face to surface through the center for
ever. and would not become stationary at
any point.
10 c. G.. writing to The Star, suggests
that 1t would be a good thing to settle the
matter once for all by leaving it to Profess
sor Simon Newcomb, or one of the other
astronomers at the Naval Observatory. On
his own account he furnishes a solution.
using the ordinary formulas of physics in
support of his contention that the ball
would never pass the center of the earth.
He says:
IS S. X states that the center Of the
ball would have acquired its highest We
locity and would continue to the other side
OF the earth with retarded velocity until
1t came to rest at that surface and then
would fall back 10 the other side, ad in
fnitum. To do as $. s. K. says, 1t must
have it's maximum momentum or energy
at the center, i.e. the momentum and
energy must be at maximum at. the
earths center. 1t seems clear. and s. 8.
K. admits it. that the weight and mass
of the ball at the 'earth's center will be
zero, and If they are zero then the momen-
tum. the energy and the velocity will also
be zero. as zero substituted In the for
| mula for mass will reduce these formulate
to Zero and no reason is seen why the
ball will not come to rest at the center
just as stalled i'll The Star.
1.-The truth of the matter Is that after
the ball has left the earth's surface on it's
Journey to the center It no longer Zap
parently) follows the same law as that of
a falling body dropping to the earth from
left a certain mass of the earth behind 1t
in its trail which attracts and retards the
bah: and although its velocity for time
at first. apparently increases, according to
Ugh. in which Is the attraction of gray
itation. 32.2 lbs. and h is the height
through WHICH the ball falls this velocity
will gradually cease to follow this formula
as the mass Of eorth 1t leaves behind in
creases. The point will be reached when
the retarding force Is greater than the I'M
| ball, so that 1t will, finally come to rest on
the first drop. at the center, as stated in
The Star - - .4t- ~
some Other Opinions.
Another writer says:
There Is a decided flaw in the argument
| of 9, s. K. Let us suppose the ball to be
at the surface about to begin it's fall. 1t
would now be attracted by the entire mass
of the EARTH and ITS acceleration due to
gravity would be equal to the value Of
gravity at the earth's surface. But. sup
pose 1t to be at some point, say. one thous-
and miles from the earth's center. At this
instant it is surrounded by a shell of the
earth. 1900 miles In thickness. which does
rot attract 1t in any way. and all that
does attract 1t is the remainder of the
earth, a sphere 900 miles in radius. con-
| centric with the earth. Consequently. at
this instant. the attracting mass being less
than when the bail was nearer the surface,
the acceleration Will he less and the speed
| of the ball will be diminished as 1t ap-
proaches the center of gravity.
When the ball reaches the center, there
will be no attracting mass of the EARTH
and the 100-lb cannon ball will remain sus-
Tended at the center of gravity. instead of
| pursuing Its course OF endless vibration as
| mapped out by 5. 8. K"
| An ingenious. II not accurate. solution is
| submitted by w. L. Lightbourn, who says:
That the supposed hole would necessar-
| lily be filled with atmosphere with increased
| density at the center of the globe. which
| would offer considerable resistance to the
! motion of the falling bal-enough per-
| haps to make it quite warm. or even hot
| and this resistance would prevent its
reaching the surface on the other side and
ceeding flight until finally it would come
| to rest at the center Of the earth and re-
| main suspended there until crowded out of
position by some heavier mass
The original answer and that of S. S. K
| are both wrong, according to X Y. H., who
writes as follows:
| by one of the laws Of physics, the
| weight of a body above the surface Of the
| earth decreases as the square Of the dis
| lance from the center Of the earth, ie, a
! ball weighing 100 pounds at the earth's sur
| face. on beng elevated, gradually decrea ses
| In weight in proportion to the square Of the
| distance from the center of the earth At
| the equator it would weigh less than at any
! other point on the earth's surface, that por-
| ton of the globe being farthest from the
| center. At an elevation Of 900 miles, ac-
| cording to the above rule the 1OO-pound
ball would weigh 81 pounds and by con-
| stantly increasing the distance from the
| earths center the ball becomes proportion
| ately less, until a point Is reached in in
| finite space where it will have no weight
| whatever.
by similar deduction which seems
| reasonable, for we are dealing with
| theories OF science. by decreasing the dis
| lance the ball will become heavier At the
| poles, 1T has been demonstrated that the
| same object weighs more than at any other
! portion or the earth's surface, because of
| the globes f1attened condition
| . III 1t were possible to reach the center of
! the earth by this imaginary hole. the ball
| would increase In weight In a direct propor-
| tion as the square root of the diminished
| Instance, until at the very center the ball
| would have Its greatest relative weight. and
be as stationary as dead wood"