The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1912-11-15
DISTANCE OF THE STARS.
How Astronomers Set kbout the Tas:
of Measuring It.

OF measuring u.
:. With the exception of a hundred
stars at most, We know nothing o
The distances of the individual stars
What Is the cause of this state o
ehings? 1t is owing to the fact tina
we have two eyes that we ars en-
abled not only to perceive the di-
rection in which external object.
are situated, but to get an idea ot
their distance, to localize them in
space. But this power is rather linn
tied. For distances exceeding some
hundreds Of yards it utterly fails.
The reason is that the distance be-
tween the eyes as compared with
the distance TO be evsluated be-
comes too small. instruments have
been devised by which the distance
between the eyes is, as it were, arti-
fcially increased. With a good in
strument of this sort distances Of
several miles may be evaluated. For
still greater distances we may i'm
agine each eye replaced by photo
graphic plate. Even this would be
quite sufficient for one of the heay-
enly bodies-viz, for the moon.
At one and the same moment let
a photograph of the moon and the
surrounding stars be taken both at
the Cape observatory aud at the
Royal observatory at Greenwich.
Placing the two photographs side by
side in the stereoscope, we shall
clearly see the moon hanging In
space" and may evaluate its dis
tance.
But 'or the sun and the nearest
planets, our next neighbors in the
universe after the moon, the diff
Guilty recommences.
The reason Is that any available
distance on the earth, taken as eye
distance. Is rather small for the
purpose. However, owing to in,
credible perseverance and skill of
several observers and by substitut-
Ing the most refined measurement
for stereoscopic examination, as
tronomers have succeeded in over
coming the difficulty for the sun. II
think We may say that at present.
we know its distance TO within q,
thousandth part of its amount.
Knowing the suns distance, we get
that of all the planets by a weli'
known relation existing between the
distances.
But now for the fixed stars
which must be hundreds Of thou
sands of times farther removed than
the sun. There evidently can be no.
question Of any sufficient eye dis
tance on our earth. Meanwhile ourl
success with the sun has provided
Us with a new one distance, 24,000j
times greater than any possible eyei
distance on the earth, for now that !
we know the distance at which thei
earth travels in its orbit around the
sun we can take the diameter Of It's J
orbit as our eye distance. Photo
graphs taken at periods six months
apart will represent the stellar
world as seen from poipts the dis
lance between which is already best,
in the time it would take
light to traverse it. The time would
be about sixteen minutes.
However, even this distance, i'm
nense as it is, is, on the whole, in
adequate for obtaining o stereo-'
'copio view Of the stars. It is only; /;
n quite exceptional cases that pho
ographs on large Sale-that is, !
,btained by the aid of big tele- !
!copes-show any stereoscopic eff
'ect for fixed stars. BY accurate
measurement OF the photos We maya
perhaps get somewhat beyond what !
We can attain by simple Microscopic
but, as we said a mo- .
neRt ago, astronomers have not sue
,eeded in tbs way in determining
he dlstanoe of more than a hun |
lred stars in all Scientific Ameri- Z
.on 4