The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1909-12-24
DISTANCE OF THE STARS.
How Astronomers Set About the Tasa
Of Measuring II.

With the exception Of a hundred
star. at m1si. sc know Nothing Of
the distan. Is Of the individual stars.
What Is the cause OF this state of
things? II is owing to the fact that
We have t@o eyes that we are en-
abled not only TO perceive the d.
reciion in which external objects
are situated. BIT 10 Cct an idea Of
their distance. 10 local.ge them in
space. But this power is rather linl-
tied. For stances exceeding ONE
hundreds of yard. it utterly fails.
The reason is that tie distance be-
tween the ewes as compared with
the distance 10 lie cyalaated be-
comes too small instruments have
been devised by which tie distance
between tho eyes is. "a it were. arti-
fcially increased. With GOOD in
strument Of this sort distances Of
several miles may he eyaIlatcd. For
still greater distances We may i'm,
agine each cye replaced by photo
graphic pix te Even this would lie
quite sufficient for one of the heay-
enly bodies-viz. for the moon.
At one aad the same moment let
a photograph Of the moon and the
surrounding stars be taken both at
the Cape observatory and al the
ROYAL observatory at Greenwich.
Placing the two photographs side by
side in the stereoscopc, we shall
clearly see the moon changing in
space" and may evaluate its dis
tance.
But for the sun and the nearest
planets, our. next neighbors in tie
universe alter the moon, the diff
cultv recommences.
The reason is that any available
distance on the earth, taken as eve
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 stereoscopie examination, as
tronomers have succeeded in over
coming the difficulty for the sun. /
think we NAV say that at present
we know its distance to within a
thousandth part Of its amount.
Knowing the suns distance, we get
that Of all the planets by well
known relation existing between the
planetary distances.
But nov, for the fixed stars,
which must be hundreds Of thou
sands ~ times farther removed than
the sun. There evidently can be no
question 81 my sufficient eve dis
tance or our earth. Meanwhile our
SUCCESS wilh the sun has provided
ns with = new one distance, $4,000
times +at4ieT il'.n any possible eve
distance on the earth. for row that
we know ttc distance at which the
earth travels IN its orbit around the
sun we can take The diameter OF its
orbit as our eye distance Photo
graphs taken at periods six months
apart will represent the stellar
world as seen from points the dis
tancc between which is already best
expressed in the time it would take
light to traverse it. The time would
be about sixteen minutes.
However. even this distance, i'm
mense as il Is. is. on the whole, in
adequate for obtaining a stereo-
scopic view of the stars. 1t is only
in quite exceptional cases that pho
tographs on large scale-that is,
obtained by the aid of big tele-
scopes-show any stereoscopic ef-
feet for fixed stars. BY accurate
measurement OF the photos we may
perhaps get somewhat beyond what
we can attain BY simple stereoscopic
inspection; but, as we said a mo-
ment ago. astronomers have not sue
ceelel in this way in determining
the distance of more than hun
dred stars in Scientific Ameri-
onn