The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1890-05-15

strong hundred-pounder quits the gun
with speed of about four hundred |
yards per second; now, if this velocity |
could be kept up, it would require no |
fewer than ten million years before the |
ball could reach Sirius! Again, take |
the sw1ftest form of velocity of which |
we have any knowledge, light, which |
travels at the rate of nearly two hun
dred thousand miles per second, or about |
twelve million miles minute, yet the |
distance of Sirius is so vast that it takes |
nearly twenty years for it's light to |
reach US; so that if Sirius was suddenly |
to become extinct, we should not be ac-
quainted with the fact till twenty years
hence.
Now, the work the astronomer has to |
do in order to calculate these distances
is one of the greatest problems he has
to solve, and the manner of his investi-
cation may not be out of place. BY way
| of illustration, take room having two
windows looking in the same direction:
now stand at one window and select a
certain object, say tree, and notice the
position in which it stands in relation
to its surroundings; then look from the
| other window at the same object, and
| you will find that its surroundings have
slightly changed; they have apparently
shifted their position, owing to your
having observed them from a different
point of view. This is precisely what
an astronomer does to determine the
distance of star; the earth in her wide
circuit round the sun is in winter on
the opposite side of the sun to what she
was in summer, and consequently the
earth'S distance from the sun being
| about ninety-one million miles, we see
the stars from two different points of
view, one hundred and eighty millions
of miles apart. But vast as is this base
line, any change in the position of
star is, with one or two exceptions, al
together inappreciable, and Sirius
stands barely within the limits of any
approximate estimation. In fact, this
star, viewed from the two extremes of
the earth's orbit, shows a displacement
of position equal to about the five
thousandth part of the moons diameter,
so that it is almost impossible for as
tronomers to determine the distance or
dimensions of Sirius by this means.
Bright as the Dog-star appears to the
naked eye, in the telescope it appears as
a mere point of light; and even in the
largest telescopes constructed, though
it's light is greatly increased, definite
disc or outline, as is seen in the planets,
is quite undiscernible; for if the power
of telescope was sufficient to ''raise a
disc on the star, it would be almost an
impossibility to distinguish it, owing to
its great brillianey; for as Sir William
Herschel tells us, when Sirius was about
to enter the field of view of his forty
feet reflector, 1.-THE light resembled that
/. which announces the approach Of sun
rise;" and when the star was in the field
of view sit appeared in all the splendor
of the rising sun, so that it was impos-
sible to behold it without pain to the
eye"
| Now, if astronomers could measure
, the disc of Sirius, they could from that
! determine its distance and measure its
, dimensions; but as no outline is appreci-
} able, they resort to comparing the light
: received from this star with that which
5 we receive from the sun, and by this
| means they are able to form some con-
: clusion as to its probable size. After
the most careful comparison of the
, light of Sirius, the sun and other stars,
; astronomers agree in fixing the volume
( of Sirius as exceeding our sun nearly
, five thousand times, and his diameter
j, as exceeding our suns seventeen times,
+ SO that the diameter of this giant orb is
! probably no less than over fourteen mil
: lions of miles!"
= To the philosophers and scientists Of
' the last century, it must have appeared
= incredible that at any future time scien
r tifc discoveries would have enabled us
: to tell with certainly the composition o.
t the stars. Yet during the last fifty
{ wears the science of spectrum analysis
: has so far advanced, as to give us unde
r niable proof of the existence OF certain
t elements in the sun and also in the
V stars similar to those with which we art
t acquainted on earth As DIR. Higgins
It SAYS: 'We now need not teach our chill
G dren that little couplet Twinkle
y twinkle, little star, how wonder wha
d you arep because we really know; w
# have in the place of wonder, knowl
b edge.' Of this method of ascerta1nlnI
J. the composition of distant body by 1t
r light, it is sufficient here to remark tina
4 it is due to the fact that, when ray o
IS light has by means of the spectroscop
/" passed through glass prism, it i
e spread out into broad band comprising
It all the colors of the rainbow. Thi
i, band or spectrum is in the case OF tn
i sun and other similar bodies crossed D.
IS a number of fine dark lines, which col
If respond to the various elements presen
It in their constitution. Now, if certai
IS gases, such as hydrogen or sodium, b
sr burnt and their spectra examined, line
70 similar to those in the suns spectrum
1t will bo found; and if the two are CON
,e pared, the presence or absence OF sue
N elements in the sun may be inferred
ar BY this means of spectrum analysis
s; has been found that the sun contains
Of large number of terrestrial elements, II
n cluding hydrogen, iron, sodium, magn'
st stun, zinc, lithium, copper, oxygen an
,e many others; of these, the first fol
"a mentioned have been discovered