The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1873-07-12
THE STAR SIRIUS.

The apparent orbit of Sirius, the dog
STAR" to whose ascendancy the heat of
hydrophobia at this season have from time
immemorial been attributed, is at the pres
emit time 30 near to that of the sun that
the star is invisible to US. But although
absent from our nightly field of stellar OBJ
servation, we are continually reminded, by
the thermometer and otherwise, of the sup
posed influence of this body; and a few
considerations of its peculiarities will not,
therefore, be out of place.
Of the enormous distance of Sirius and
the other stars, no adequate conception
can be formed but here statistics come to
our aid. 1t has been demonstrated that, if
our sun was removed to the distance of the
nearest 50 called fixed star, it would assume
the apparent size of a star of the second
magnitude. But Sirius is many times as
far from our earth as the nearest fixed
star, and its immense separation may be
formulated by stating that it is 1855
times the radius of the earths orbit away
from cur planet. This radius equals 3d.
400, 900 miles, and the result of the calcu-
lation astounds us with its magnitude, and
leads us to still further establishment It the
distance of the multitudinous bodies of
pebuln which, when congregated millions
together, scarcely suffice, in some instances
to render the aggregation visible to the un-
aided eye.
Such is the enormous mass of the star
Sirius that it has frequently been supposed
to be the centre of the universe, as far as
our powers of research can reach. 1t is
certainly possible that our whole solar sys-
tenn is revolving around this one particular
star, but it's obviously increasing distance
points out the deduction that the orbit of
the system is an eccentric one, and that its
center is still travelling away from that
part of the heavens with which we are
familiar. Of the rate at which Sirius is
leaving us behind, it is sufficient to give
the results of the best astronomical obser-
walton. Mr.. Higgins, whose discoveries
with tho spectroscope have done much to
make us familiar with the enormous pow
ers of that invaluable instrument, has found
by watching the hydrogen line given by
this star that its displacement equals l $50
of an inch towards the red end of the spec
trum, and he deduces fran this fact that
the refrangibility of the light of Sirius is
much diminished, as the red are the least
refrangible of all the eolered rays, and this
is complete proof that Sirius is receding
from the earth. Then the question arises
At what rate is this retrograde melton TAX
ing place? Computation from the spec
trum gives it at about Al miles per second;
but at the time in question, the earth was,
by its own revolution, receding from Sirius
at the rate of 10 miles per second, and the
motion of our whole solar system accounts
reduces Sirius retrograde speed to about
24J miles per second. Further modifying
this figure by the result of Sirius TRAVERSE
motion, we arrive at 90 miles per second, or
900, 900, 900 miles per year.
| What result does this enormous increase
of distance have upon this star, so we'll
known to us in the wiltry heavens? Sirius
is the fiery red Sothis Of the Egyptians, and
Seneca described it as being redder than
Mars. But in these days it shines with a
perfectly white light, and it was so even in
the days of the Danish astronomer Tycho
Brahe. Its rapid recession is thus causing
constantly varying change in its color
Whether any further mutation in its aspect
will take place during the lives Of our now
living observers, it would, perhaps be pre-
sumptuous to predict and as to what color
it will next assume we have no guide. At
it's present rate of travel, it will take 80, 900
years to double its distance, and as it is now
a star of the first magnitude, almost an in
finity of time must elapse before it is no
longer accessible to the instruments of
modern astronomers.
However we must believe the effect OF
the ascendancy of the dog star to be a mere
event with the hot weather of summer is
mere coincidence, and dogs are affected by
rabies and men by sun-stroke without
regard to the position of Sirius in the
heavens. Indeed, the so called dog days
according to the almanac, are over before
the star rises with the sun, and thus are
twenty days too early to be justified by the
theory that caused the ancients to describe
them as the cGniculares. There is no doubt,
therefore, that the effects Of summer heat
will continue long after the power Of Sirius
in our skies is considerably diminished !;
and the dog days must certainly be consid-
cred as curious tradition, only important
so far as it throws light on thecondition of
learning among the ancients.