The Indianapolis journal., 1888-09-10
A BIT OF ASTRONOMY.
The Cluster Of Stars Tn Which Our Sun BE.

Prof. Holden, in September Century.
The Uranometris Nova Of Areelander gave
the positions of the lucid stars of the northern
sky. and IL has BEEN supplemented by the
Uranomeiria Argentine of DR.. Gould, which
covers the southern sky. With the stellar
statistics of the whole sky before him DIR. Gould
wac in position TO draw some extremely in
terestine conclusions with respect TO the
arrangement of the brighter stars in space. and
TO the situation OF our solar system in relation
to them. TIE outline OF his reasoning can be
given here, but the numerical evidence upou
which bis conclusions are founded must BE
omitted. In the first place. it is fairly proved
that in general tho stars that are visibs
distributed at approximately equal distances
one from another. and that on the average
they are of approximately equal brilliancy. IL
We make a table OF the number Of stars of each
separate magnitude in the whole sky We shall
find that there are proportionately mary
more of the brighter ones from first TO four Ia
magnitudesl than the fainter from fourth 10
seventh nagnitIdes.l That il, there il al 'uu-
failing aud systematic excess OK the observed
number of the brighter stars We cannot sup
pose, taking one star with another, that the
difference between their appsrant brightness
arises simply from real difference ia size, but
We ust conclude that the stars from the first
to fourth magnitudes lsome 500l are really near
er TO us than the fainter stars. 1t therefore
follows that these brighter stars form a svstAri
whose separation from that of those OF the
fainter stars ia marked By the change OF relative
numerical frequency.
What. then, is the shape % this system, and
have we any independent proof OF its existencei
Sir John Hersehel and DIR. Gould have pn;nied
out that there is In the sky belt of brighter
stars which is very nearly great circle 0f tho
sphere. This belt il plainly marked. and j, IL
inclined about So 10 the Milky Way. which it
crosses near Cassiopes and the Southern Cross
Taking sll the stars down to 30 Iacuitude D-
Gould shows that thew are more syrnfnst-iceliy
arranged with reference to this belt than :h-y
are with reference To the Milky Way. In fart.
the belt has 264 stars on one side OF II and 3s3
on the other while the corresponding numbers
for the Milky Way are 245 and 2e2 From
this aid other reasons il is concluded that th's
belt contains brighter stars becaus" it conts'ns
the nearest stars and that ;hs set of nearer and
brighter stars lie distinctly the cluster ~ wfieh
our sun belongs. Leaving out the hrig ghter -
which may be accidentally projected among ihe
true stars belonging to this cluster. DR. CuGli
about 400 stars; that il lies in The principal
stars 10 a great. not a small crrle': and that
this solar cluster is independent af the vast can
geries Of stars which We call the Milky Way.
I'VE know that the sun is moving in enace
IL becomes a question whether this motion i
one common to the solar cluster aud 20 the san.
or only the motion OF the SUI in the solar clrs-
ter. The motion has bsen determined the
supposition that the sun Is moving and :bat ~
motion Is not systematically shared by the stars
which DR.. Gould assigns 10 the solsr cluster.
Bot very important research will be TO inves'i-
| gate the solar motion without employing these
| 400 stars es data"