The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1910-06-03
DISTANCE OF THE STARS.
How Astronomers Set About the Tasa
Of Measuring II.

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? 1t is owing to the fact that
we have two eyes that we are en-
abled not only to perceive the di-
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 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 evaluated be-
comes too small Instruments have
been devised by which the distance
between the ewes 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 heav-
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
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 evaluate its dis
tancc.
But for the sun and the nearest
planets, our newt 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
think we may say that at present
we know It's 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
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 eve dis ,
lance on our earth. Meanwhile our
success with the sun has provided ,
rs with a new one distance, $4,000 ,
hines greater than any possible eve !
distance on the earth, for now that /,
We know the distance at which the !;
,arth travels in its orbit around the :
iun we can take the diameter of its }
'rbit as our eve distance. Photo !
-raphs taken at periods six months :
part Will represent the stellar
world as seen from points the dis :
ance between which is already best !
in the time it would take :
ight to traverse it. The time would :
e about sixteen minutes. !
However. even this distance, i'm !,
nense as il is, is, on the whole, in :,
dequate for obtaining a stereo- :,
copic view Of the stars. 1t is only q
q quite exceptional cases that pho "
ograqhs on large scale-that is, n
btaincd by the aid of big tele- :,
ropcs-show any stereoscopic eff i
ect for fixed stars. BY accurate i
of the photos we may II
erhaps get somewhat beyond what n
e can attain by simple stereoscopic ~,
but, as we said a mo-
lent ago, astronomers have not sue
ae1ed in this way in determining
le distance Of more than a hun
red stars in Scientific Ameri- bc
IN. a