The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1909-05-07
DISTANCE OF THE STARS
How Astronousrs Set About the Tssk
Of Measuring IL

Of Measuring IL
With the exception of hundred
,tars at most, we know nothing of
the distances Of the individual stars.
What is the cause Of this state OF
things? 1t is owing to the fact that
we have two eyes that We are en-
abled not only TO perceive the dl-
rection in which external objects
are situated, but TO get an idea OF
their distance, to localize them In
space. But this power is rather Inn
tied. For distances exceeding some
hundreds of yards it utterly fails.
The reason is that the distance be-
tween the ewes as compared with
the distance TO be eyaluated be-
comes too small. instruments have
been devised by which the distance
between the ewes Is, as II were, artl-
fcially increased. With 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 and at the
Roval 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 for the sun and the nearest
planets, our next neighbors In the
universe after the moon, the diill-
Guilty 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 oil
, several observers and by substltut-
I ing the most refined measurement
e for stereoscopic examination, as
4 tronomers have succeeded in over
q coming the difficulty for the sun.
4 think we may say that at present
o we know its distance TO within a
thousandth part of Its amount.
: knowing the suns distance, we get
e that of all the planets by a well
7 known relation existing between the
d planetary distances.
: But now for the fixed stars,
Q which must be hundreds OF thou
d sands Of times farther removed than
d the sun. There evidently can be no
e question of any sufficient eye dis
n lance on our earth. Meanwhile our
Is success with the sun has provided
l. us with a new one distance, 24,OOO
Ie times greater than any possible eye
4 distance on the earth, for now that
we know the distance at which the
lie earth travels in its orbit around the
k sun we can take the diameter OF Its
orbit as our eve distance. Photo
10 graphs taken at periods six months
ee apart will represent the stellar
world as seen from points the dis
ut tance between which is already bes'
IN expressed in the time il would tax,
m light to traverse it, The time woulC
be about sixteen minutes.
Id However, even this distance, i'm
mense as il is, is, on the whole, in
d. adequate for obtaining stereo
I'M seopic view Of the stars. 1t is onl.
in quite exceptional cases that pho
in tographs on a large scale-that Is
-as obtained by the aid of big tele
vol scopes-show any stereoscopic ei
re feet for fixed stars. BY accurat
m measurement of the photos we ma
lid perhaps get somewhat beyond wha
ed we car attain BY simple stereoscopl
" inspection; but, as we said me
TO olment ago, astronomers have not sue
he ceeded in this way in determinln
the distance Of more than hur
sre dred stars in all.-Scientihc Amer
arlran.