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Page 63
But we have had, within a few years, fine opportunities [Page 224]
to study, with improved instruments, two new stars; On the evening
of May 12th, 1866, a star of the second magnitude was observed in
the Northern Crown, where no star above the fifth magnitude had been
twenty-four hours before. In Argelander's chart a star of the tenth
magnitude occupies the place. May 13th it had declined to the third
magnitude, May 16th to the fourth, May 17th to the fifth, May 19th
to the seventh, May 31st to the ninth, and has since diminished to
the tenth. The spectroscope showed it to be a star in the usual
condition; but through the usual colored spectrum, crossed with
bright lines, shone four bright lines, two of which indicated
glowing hydrogen. Here was plenty of proof that an unusual amount of
this gas had given this sun its sudden flame. As the hydrogen burned
out the star grew dim.
Two theories immediately presented themselves: First, that vast
volumes had been liberated from within the orb by some sudden breaking
up of the doors of its great deeps; or, second, this star had
precipitated upon itself, by attraction, some other sun or planet,
the force of whose impact had been changed into heat.
Though we see the liberated hydrogen of our sun burst up with sudden
flame, it can hardly be supposed that enough could be liberated
at once to increase the light and heat one hundred-fold.
In regard to the second theory, it is capable of proof that two
suns half as large as ours, moving at a velocity of four hundred
and seventy-six miles per second, would evolve heat enough to supply
the radiation of our sun for fifty million years. How could it be
possible for a sun like this newly blazing orb to cool off to such a
[Page 225] degree in a month? Besides, there would not be one chance
in a thousand for two orbs to come directly together. They would
revolve about each other till a kind of grazing contact of grinding
worlds would slowly kindle the ultimate heat.
It is far more likely that this star encountered an enormous stream
of meteoric bodies, or perhaps absorbed a whole comet, that laid
its million leagues of tail as fuel on the central fire. Only let
it be remembered that the fuel is far more force than substance.
Allusion has already been made to the sudden brightening of our
sun on the first day of September, 1859. That was caused, no doubt,
by the fall of large meteors, following in the train of the comet
of 1843, or some other comet. What the effect would have been, had
the whole mass of the comet been absorbed, cannot be imagined.
Another new star lately appeared in Cygnus, near the famous star
61--the first star in the northern hemisphere whose distance was
determined. It was first seen November 24th, 1876, as a third magnitude
star of a yellow color. By December 2d it had sunk to the fourth
magnitude, and changed to a greenish color. It had then three bright
hydrogen lines, the strong double sodium line, and others, which
made, it strongly resemble the spectrum of the chromosphere of our
sun. An entirely different result appeared in the fading of these
two stars. In the case of the star in the Crown, the extraordinary
light was the first to fade, leaving the usual stellar spectrum. In
the case of the star in Cygnus, the part of the spectrum belonging
to stellar light was the first to fade, leaving the bright lines;
that is, the gas of one gave way to regular starlight, and the
starlight [Page 226] of the other having faded, the regular light of
the glowing gas continued. By some strange oversight, no one studied
the star again for six months. In September and November, 1877, the
light of this star was found to be blue, and not to be starlight at
all. It had no rainbow spectrum, only one kind of rays, and hence
only one color. Its sole spectroscopic line is believed to be that
of glowing nitrogen gas. We have then, probably, in the star of
1876, a body shining by a feeble and undiscernible light, surrounded
by a discernible immensity of light of nitrogen gas. This is its
usual condition; but if a flight of meteors should raise the heat of
the central body so as to outshine the nebulous envelope, we should
have the conditions we discovered in November, 1876. But a rapid
cooling dissipates the observable light of all colors, and leaves
only the glowing gas of one color.
_Movements of Stars._
We call the stars _fixed_, but motion and life are necessary to all
things. Besides the motion in the line of sight described already,
there is motion in every other conceivable direction. We knew Sirius
moved before we had found the cause. We know that our sun moves
back and forth in his easy bed one-half his vast diameter, as the
larger planets combine their influence on one side or the other.
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