The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1914-04-10
DISTANCE OF THE STARS.
How Astronomers Set About the Tssk
of Measuring IL.

With the exception of hundred
stars at most, We know nothing of
the distances Of the individual stars.
What is the cause of this state OF
things? Ii IS owing 10 the fact that
We have two ewes that we are en:
akled not only to perceive the liz
rection in which external objects
are Situated, bat TO get an idea OF
their distance, 10 localize them In
space. But tins power Is rather limS
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 evaluated be-.
comes too small. Instruments have.
been devieo1 lY '~hich the distance
between o. is. ~ it we're, art-'
ficially in ea>eo. With a good In
strumcnt cf this sort distances OF;
several nils rav l,c evaluated. For,
still greater distances we may i'm
ag:ne each eve Ter. lced by photo
graphic n q. Even this would be
quite SUI! est for one Of the heav-
enly bodies-viz, for the moon.
At one and the same moment let
photograph of the moon and the
suKounding stars = taken both at
the Cape observatory and at the
Royal observatory at Greenwich.
Placing the two photographs side by
side in the stereoscOpe, we shall
clearly see the moon changing in
space and may cyaluate its dis
tance.
But for the sun and the nearest
planets, our next neighbors in the
universe after the moon, the diff
Guilty recommences.
The reason is that any availssle
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 substitHlt-
Ing the most ro2re Measurement
for stereoscopic examination, as
tronomers have succeeded IN over
coming the difficulty for the sun l
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 well
known relation existing between the
planetary 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 our
success with the sun has provided
US with a new one distance, $4,000
times greater than any possible eye
distance on the earth, for now that
we know the distance at which the
earth travels in its orbit around the
sun we can take the diameter of It's
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
expressed in the time it would take
light to traverse it. The time would
I be about sixteen minutes.
However, even this distance, i'm
mense as il Is, Is, on the whole, In
, adequate for obtarniDg a stereo-
ucopic view of the stars. 1t IS only
' ln quite exceptional cases that pho.
j tographs on a large scale-that is
obtained by tie aid of big tele'
j. scopes-show any stereoscopic ef
t feet for fixed stars. By accurate
i measurement of the photos we may
$ pefhaps get somewhat beyond what
We can attain by simple stereoscopi'
: iHenection; but, as We said a mo
n,eut ago, astronomers have not sue
ceeJcd in this way in determining
tie distance of more than hun
dred stars in all.--Scientific Ameri
can