The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1914-07-31
DISTANCE OF THE STARS.
How Astronomers Set About the Tass
Of Measuring IL.

]
Of Measuring IL.
With the exception of a 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 tie 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 locaize 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 bv which the distance
betUeon csc, Is. as it we're, arti-
fciaIiy Increased With a good in
strumeat 81 this sort distances OF
several mios mar be evaluated. For
still greaic tences we may i'm
agine each e,c renaced by photo
graphic D te. Even this would be
quite sufficient for one Of the heav-
enly bod.es 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 stcreosccpe, We shall
clearly see the moon changing in
space" and may eyaluate 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 eye
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 e&appaion, as
tronomers have sueeeeded In. over
coming the difficulty for the sun. I
think we isay 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
the sun. There evidently can be no
question of any sufficient eye dis
lance on our earth. Meanwhile our
success with the sun has provided
Us with a new one distance, $4,000
Zines greater than any possible eve
on the earth, for now that
We know the distance at which the
earth travels in It's orbit around the
;un We can take the diameter of It's
'rbit as our eye distance. Photo
yraphS 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
light to traverse it. The time would
,e about sixteen minutes.
However, even this distance, i'm
nense as it Is, Is. on the whole, in
.dequate for obtaining a stereo-
copic view of tie stars 1t is only
n quite exceptional cases that pho
ographs OF large scale-that is,
btained bv the aid of big tele-
copes-show any stereoscopic ef-
eet for fixed stars. BY accurate
of the photos We may
erhaps get somewhat beyond what
re can attain by simple ste1eoscopic
but, as we said 8 mo-
rent ago, astronomers have not sue
eeded in this way in determining
he distance of more than a hur-
red stars in all.~-Scientifc Ameri-