Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1910-03-25
Miseellaneoa5 8eadina.
COLOSSAL ARCTURUS.
The Fourth Brightest Star In All the
Heavens.


our sun as being the largest body in
the heavens. the grand high lord
of all the little planets and the twink
ling stars. Such Is very far from be-
ing the case. Practically all of the
fixed and twinkling stars are as large
las. and some even larger than. our
own sun. They appear small only
because of their great distance. for
they are just as truly suns with fami-
lies of planets flying around them as
is our central orb.
There is one of these stars in par
ticular that has attracted the atten-
tion of astronomers, not only on ac-
count of its great size, but also its
enormous distance from our solar sys-
TEN. This is the star Arcturus. To
have some conception of the almost
| inconceivable distance that separates
| ii from us the astronomical standard
of measuring distance must be COM
pretended Now, light does not come
from a luminous body instantaneously
to our eyes. 1t takes time to come,
because it is wave molten in a
medium The velocity of light as
most recently determined is about
lS6. 900 miles a second. Multiply this
by the number of seconds in a year
and we have distance known in as
tronomy as a light year. Therefore
when a star is. say, six million miles
away we say it is one light year off,
which means that the light from the
star takes one year to reach us. 1t
may be Of some interest to know that
there is no fixed star less than ten
light years away, or sixty trillion
miles This is the one known as Alpha
| Centauri. Most of the stars are much
farther even than that, Arcturus being
the farthest one measured to date.
Arcturus is thought to be at least
a hundred times larger than the sun
in diameter. That would make it
10000 times larger in surface, or the
dimension that is ordinarily COM
pared By means of the photometer
Its brightness has been determined to
be 5000 times that Of the SUM- 1t is
the fourth brightest star in all the
heavens, Sirius the dog star, being
first in brightness. AS regards the
distance from us, it has been found
to be a little over $50 light years, or
$50 trillon miles. This distance, of
course, cannot be conceived by NOR
1 to1 &c err
amazing. However, one can get a
slight idea Of it by means Of an every
day analogy. Think Of the fastest
express train going at the rate Of
100 miles an hour toward such a star
and compare the time it would take.
1t is found TO be in round numbers
exactly 120.0OO,0O0 years! Now, as
we know that it has taken its light
so long to come to us and as there are
a great many stars whose distance
has never been measured exactly, but
which have been computed to be ap-
proximately several million light years
away, we have absolute proof of the
great age Of the world and the stel-
lar universe.
The elements composing the sun
Arcturus are, peculiarly enough, very
nearly the same as our sun. AS it is
one of the most wonderful and as
founding things that a scientist can
tell what a star so far away is COM
posed of, a small explanation of the
modus operandi would not come
amiss here. 1t is done by means of a
small instrument known as the spec
troscope, which consists Of glass
prisms so arranged as to split up the
light falling on them into its cOnstit-
uent parts. Now, every substance has
the power to cause a certain color or
line in the spectrOscOpe if it is in a
luminous condition, so this instru-
ment is simply pointed at the star
whose composition is sought, and If
any line is found that corresponds to
a substance that we know about we
assume that this substance is found
in the star examined.
Another interesting thing is the
method pursued in determining the
great distance of stars. This is done
by determining their parallaX or an
gle made at the star between two rays
from the star striking at two differ
ent points in space. As the greatest
distance that we can measure off in
this way aud still take the angle Is
1.-The diameter of the earth's orbit, that
distance is invariably used. 1t is al
most 200.O0O.000 miles. but that. as is
seen. is very small compared with the
lenOrmOuS distance of the star. Now,
the angle thus measured from Arc
turus is only two-hundredths of a
second. When it is remembered that
there are 60 seconds in q minute, SO
minutes I'm a degree and $50 degrees
in a circle, II Is at once seen what a
small angle the parallaX is and how
lcareful the astronomer has to be In
his observations. Indeed, for a long
time, before modern delicately meas
Turing instruments were invented, no
stars distance could be found, for
there was seemingly no angle form
ed, and thus the old scientists had to
assume the star to be at infinity.-
PittSburg Dispatch.