The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1915-01-22
DISTANCE OF THE STARS.
How Astronomers Set About the Tass
of Measuring Ii.


With the exception of a hundre,
stars at most, we know nothing o
the distances of the Individual stars
What is the cause of this state O
things? 1t is owing 10 the fact tha
we have two eyes. that we are en-
abled not only TO perceive the di
rection in which external object.
are situated, bat to get an idea Of
their distance, to localize them il
space. But this1powcr is rather lin
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 eyaluated be-
comes too small< Instruments have
been devised by which the distance
between the eyes is, as it were. arr
fcially increased. With a good in
strument of this sort distances q
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
qaite sufficient for one of the heav-
enly bodies-yiz, 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 ard at the
Royal observatory at Greenwich.
Placing the two photographs side BY
side in the stereoscope, we shall
clearly see the Amoon Changing 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 diff
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 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. I T
think we may say that at present
we know its distance to within
thousandth part Of its amount.
Knowing the suns distance, we get
that Of all the planets by a well
known relation existing between the
distances
But now for the fixed stars,
which must be hundreds Of thou
sands of times farther removed than
he sun. There evidently can be no
question of any sufficient eye dis
;ance on our earth. Meanwhile our
success with the sun has provided
Is with new one distance, $4,000
lines greater than any possible eve !
listance on the earth, for now that
We know the distance at which the :
arth travels in its orbit around the
un we can take the diameter of its
rbit as our eye distance. Photo
raphs taken at periods six months .
part will represent the stellar
Torld as seen from points the dis c
ance between which is already best ?
xpressed in the time it would take .
ght to traverse it. The time would K
e about sixteen minutes. {
However, even this distance, i'm o
lense as it is, is. on the whole. in. n
dequate for obtaining stereo- 81
,opic view of tie stars. 1t is on'r "
quite exceptional cases that pho a
'graphs OF a large scalc- lat is 81
btained by the aid of big tale e.
,opes-show any stereosconic el II
'ct for fixed stars. BY accurate a.
easurement of the photos we may Z
srhaps get somewhat beyond villa; 81
e can attain by simple stereoscopic &c
but, as We said a mo- &C
ent ago, astronomers have not suc- N
:eded in this way in determining ht
e distance of more than a hun Ar
ed stars in all.-Scientifc Ameri-