The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1912-06-14
4 DISTANCE OF THE STARS
Wow Astronomers Set About the Tash
of Measuring IL.

g wow astronomers Set About the Task
a of Measuring II.
4 With the exception of a hundred
: gtars at most, We know nothing Of
) Ihe 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-
recton IN which external objects
are situated, but to get an idea OF
their distance, to localize them in
space. But this power 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 he evaluated be-
comes too small. Instruments have
been devised by which the distance
between the eyes 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 heay-
emily bodies-viz, for the moon.
At one and the same moment let
asphotograph of tho 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 shalt
clearly see the moon changing in
space" and may evaluate its dis
tance.
But for the sun and the nearest
/ 'ancts, 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 examinations. as
tronomers have succeeded in over
coming the difficulty for the sun. I
think we may say that at present
we know its distance TO within
thousandth part of its amount.
Knowing the suns distance, we get
hat of all the planets by a we'll
Known relation existing between the
planetary distances.
But now for the fixed stars.
which must be hundreds of thou
ands of times farther removed than
he sun. There evidently can be no
question of any sufficient eve dis
ance on our earth. Meanwhile our
uccess with the sun has provided
IS with a new one distance, $4,000
INES greater than any possible eve
lstance on the earth, for now that
'e know the distance at which the
arth travels in its orbit around the
un we can take the diameter of its
rblt as our eve distance. Photo
raphs taken at periods six months
part Will represent the stellar
orld as seen from points the dis
lnce between which is already best
Spressed in the time it would take
ght TO traverse it. The time would
: about sixteen minutes.
However, even this distance. i'm
ense as 1t Is, is, on the whole. in
iequate for obtaining a stereo-
opic view of the stars. 1t is only
quite exceptional cases that pho
graphs on large. scale-that is.
'tained by the aid of big tele-
opesAshow any stereoscopic ef-
&C for fixed stars. By accurate
easurement Of the photos we may
rhaps get somewhat beyond what
can attain by simple stereoscopic
'pection; but, as we said a mo-
mt ago, astronomers have not sue
eded IN this way in determining
e distance of more than a hun
ed stars in all.-Scientiic Ameri-
4.