The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1882-01-04


[Richard A. Proctor in Youths Companion.l
During the Winter months one star can be
seen to the right of the glorious Orion, but low
er down, which shines more splendidly than
any other star in the heayens-though not
quite equal in brightness to either of the two
planets, Jupiter and Venus. 1t is Sirius. the
Dog-Star, and has in all ages excited the admi-
ration of all observers 1t is supposed by some
that this splendid star has changed its color
during the last 1000 years, for ancient Greek
and Roman writers spoke of it as red star,
and Seneca even said that Sirius was ruddier
than Mars. But most probably the red light
referred to by those older writers was simply
that occasional flashing of red light from the
star which you can see whenever Sirius is close
to the horizon, when, as Tennyson writes,-
sthe fiery Sirius alters hue
And bickeIs into red and emerald,
When you have learned what Sirius really is
you will see how unlikely it is that be can have
changed in color within 1000 years-a period
which seems long to us but is really as nothing
in the lifetime of star,
Bat what is Sirius? Does the telescope, which
seems to bring far objects near, tell US anything
about him, as it does about Jupiter, Saturn
and other planets? The telescope scarcely tells
us anything. The largest yet made by man
only shows Sirius as a very bright star. Sir
William Herschel tells US that when his great
telescope with its four-feet mirror was turned
toward Sirius, the approach OF the star to the
field of view reminded him of the approach OF
daybreak But when the star was fairly in
view il showed no globe like that of the sun.
1t was still mere star, though, Of course, very
much brighter than any star III the sky And
it is pretty certain that men will never be able
to make a telescope which will show the real
body of this splendid star
Yet, for all this, we know quite well what
Sirius is. He is a sun like ours, only very
much larger. He lies about eight hundred
thousand times farther from us than the sun;
and we know that if the sun were set eight
hundred times farther away than he is, he
would only look like star, and not very
bright star, either. In fact, he would only
lust be fairly visible on dark and clear night.
He would be very faint indeed compared with
Sirius, shining with only one two-hundredth
part of that stars light. Now, this does not
exactly tell us how large Sirius is, because his
great brightness may be partly due to the
greater splendor of his surface. A square inch
OF iron at white heat gives out much more
light than a square inch of iron at red beat,
and yet is not larger. So it may be that though
the surface of Sirius gives out SO much more
light than the surface of the sun, it may yet
not be much larger.
Still il seems reasonable to suppose that a
sun which is SO much more resplendent than
our own has much greater surface. / do not
think we shall be very far wrong if we suppose
that the surface of Sirius is not more than
twice as lustrous as that of our sun. Now, in
order that you may see how large Sirius is
00u1narH1 with the Orlat earth which
live, may mention that the planet Jupiter is
the giant of the solar system, exceeding our
earth in size even more, but not much more
than the sun exceeds Jupiter. Suppose that
Jupiter is represented by ball one inch in di-
smeter, then the earth on which we live would
be represented by ball rather less than
tenth OF an inch in diameter, the sun by ball
some 10 inches in diameter; and Sirius by
globe nearly three yards in diameter according
TO the small size / have given him, but more
than five and one-haif yards in diameter ac-
cording to Sir John Herschel's estimate.
There is yet another way of forming an idea
OF the vast size of that globe which yet, owing
to its enormous distance, looks like a bright
point in our skies. The moon travels at dis
lance from the earth of nearly 100000 miles, SO
that the entire span of the moons orbit is
about 4S0, 900 miles. Now the diameter of the
sun is about $4,000 miles. So that if the earth
were set at the centre of the sun, and the moon
travelling at its present distance from her, the
the globe Of the sun.
1t may seem surprising, but yet it is true,
that although astronomers have not been able
TO see, still less to measure, the globe OF Sirius
they have yet learned what it is made of-at
any rate they know some of its materials. For
instance, they know quite certainly that there
Is iron in it lin the form Of gas) and sodium and
magnesium, and there are also enormous guam
titles OF the gas called hydrogen. How this
has been learned could not very we'll explain
hoI 1lxy hot fI,a fu1u oe %ha
light OF Sirius has shown that part of the light
given out by his glowing orb is cut off by GER
tain vapor-much as part of the suns light is
cut off by vapor in our own air when the sun
is rising or setting; and just as the ruddy color
OF the sun at that time shows him to be shin
ing through the vapor of water in the air, SO
do certain peculiarities in the light of Sirius
show that that light has passed through the
vspor OF iron, s. dunn, magnesium and hydro
gen.
1t has been learned also that Sirius is rush
ing through space at the rate of from 20 to 30
miles in every second of time. He carries
along with him, no doubt, all the worlds which
travel around his globe But it must not be
supposed that this rapid motion changes his
place among the stars in way we can easily
recognize. On the contrary, SO enormous is
this suns distance that his change of place can
only be detected by means of very powerful
telescopes, or else after long periods of time.
And this leads me to consider singular dis
Gus sun. OF course it is to be supposed that
Sirius, like our sun, has family of
worlds travelling round him. This set OBJ
servers looking for any companion body which
might travel round Sirius For they saw that
any such body, to explain the movements of
Sirius, must be very large, though OF course
they expected only to find it much fainter than
Sirius himself. However, for long time they
could find no such companion. At last q fine
telescope with glass 49, inches in diameter,
made by the celebrated optician Alvin Clarke
of Cambridge, Mass, showed a faint star close
by Sirius,-that is, seemingly close, for in re-
atty it was found to be at the very least 1000
millions OF miles from him. Later the French
astronomer Goldschmidt, with much smaller
telescope, claimed to have detected five other
companion stars and 1 was recently told by
Prof. Pritchett of Glasgow, Mo-, that with
fine Pinch telescope by Alvin Clarke, he had
seen two of these. He could not understand,
however, how Goldschmidt could have seen
them with a smaller telescope, as they were
among the faintest stars he had been able to
detect with his powerful instrument. If these
companion stars are really worlds attending
Sirius and shining only by reflected light, they
must be enormous bodies. The system of Siri-
us must in that case as far surpass in size and
magnitcence the system travelling round our
san as the sun himself is surpassed in glory
and 10 might by the splendid sun we call the
Dog star.