The Jasper weekly courier., 1916-01-14
DISTANCE OF THE STARS.
81 o~S Asa. onomers Set About the Tea
OF Measuring u


With tic exception of hundred
stars at most, we know nothing OF
the distances OF the individual stsss.
VIVA Is the cause of this state of
thing. It IS owing to the fact that
se ha,c to eyes that we are en-
ahled rot only % perceive the dl-
rection in which external objects
are sltaatod, but to get an idea o.
their distance, to localize them IL
pace. / :, TN. power Is rather linz
tied. For distances exceeding eom'
hundreds of yards it utterly fails
The reason IS that the distance be
tween the eyes as compared witt
the distance to be evaluated be
comes too small. Instruments have
been devised by which the distance
between the eyes is, as it were, srh-
fciaily increased. With Q good IN.
strument Of thi&.,so distances OF
several miles may be evaluated. For
still greater distances Ee may i'm
ssins each eye replaced by photo
graphic plate. Even this would be
quite sufficient for one OF the heav-
en'y bc,.lias-viz, for the moon.
IL one a ihe same pn Y."nt LET
!. photograp pa Of the mo- - t.
SURE a,Ing stars be taken both 4,
the Cape observatory and at the
Royal observs tory at Greenwich
Placing the two photographs side by
side in ne stereoscope, We shali
clearly see the noon Changing in
space and may evaluate its dis
taDce.
But for the sun and the neares!
planets, our next neighbors In the
universe after tie moon. the daft
Acnlty recommences.
The reason 10 thai sny avsllabl1
distance on ths earth, taken rs eye
distance, ;s rather small for th'
purpose. However, owing 20 il
credible perseverance and ski o
several observers and by substitut
ing the raost refined measr, emen'
for stereo scopic examination, as
tron omcrs have succeeded in over
conIng the difficulty for the sun.
tlink we may say that at presen
We know its distance to within
thousandth part Of its amount
1 Knowing the suns distance, we &c
that % sll the planets By q vel
/ known relation existing between IN
planetary distances.
But now for the fixed STARE
1 which must be hundreds OF thou
sands of times farther removed thai
he There evidently can be n
eas q of 10y sufficient eye dii
nee on o., earth. Meanwhile on
success with the sun has provide
US ", new one distance, 24,0O
tn2es :. sater than any possible ey
distance on the earth, for now this
we know the distance at which tn
earth travels in its orbit around th
sun we can take the diameter Of il
orbit as our eye distance. Phott
graphs taken at periods 81 month
apart will represent the stelli
world as seen from points the di
tance between which is already be-
expressed in the time it would tai
light TO traverse 1t. The time woul
+, be about sixteen minutes.
However, even this distance, in
mense as Il is, is, on the whole, il
adequate for obtaining a stere
scopic view OF the stars. 1t is on
m quite exceptional cases that ph
tographs Oh a large scale-that
obtained by the aid of big tel
scopes-show any stereoscopic e
feet for fixed stars. By accura
measurement of the photos We M
perhaps get somewhat beyond VII
we can attain by simple steleoscop
Inspection; but, as We said a IN
ment ago, astronomers have not su
ceeded in this way in determinll
the distance of more than a hu
dred stars in all.--Scienti6c Amel
can