San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1891-11-09
SHALL WE BURN UP.
The Suns Envelope Is Our Protector
from Such a Fate.

There appears to be no doubt that
the radiative energy OF the sun is in
creased when the spots break out
upon It's surface, and it seems reason
able to conclude that the earth must
experience greater degree of that at
such times. YET singularly enough,
the best observations bearing up
on this question indicate
just the contrary condition of
things. 1t has been found III India
that the mean temperature in lower
instead of higher during the maxi
mum periods of the sun spots. Such
result must be brought about by
| terrestrial conditions which are able
in some way to reverse the effect of
| increased radiations from the sun.
| But very great increase in the solar
heat could hardly be neutraliZed in
that way. II, then, the sun at GER
tain times suddenly p0urs forth an
extraordinary gush of heat, the earth
must take the consequences. The
whole subject becomes particularly
| significant In view OF modern dis
| cOveTles concerning the nature
| and constitution Of such bodies as the
sun. If not in name at least in prac-
| tlCe, there exists science of cOmpar'
alive solar physics. All the suns of
space are made to contribute to cur
knowledge. Our own sun falls into
a special class, and is found To be |
sharply differen tiated in many parti- !
culars from the stars that do not be- !
long in the same category with itself. |
Even the ancients knew, or at least |
surmised, that the stars are suns,
but 1t remained for the astronomers
of our day to Onstrate that there
is great variety of Guns. |
Still, through all the variations
there runs family likeness |
and an evident identity Of |
ultimate constitution and destiny.
So the different classes of suns merge !
into one another by almost insensible |
graduatiOns. There is also evidence |
that SUBS pass from one class to an
other, either as the result OF progress
i've development or in consequence of
the sudden outbreak of trans torming |
forces. The last Iact is Of supreme |
interest to the inhabitants of a planet
which, like the earth, depends for
its prosperity, and even tor its very
existence, upon a solar orb that is
liable to stupendOus changes. The
periodical outbreak OF sun spots in
cycle of about eleven years, alone
suffices to place the sun in the large
and continually increasing list of the
so called variable stars; and the wide
difference in Il intensity of these
outbreaks at different times indicates
that We can not count upon the |
changes in the suns radiative energy !
as We do upon such comparatively |
regular variations as those of the sea-
sons, which are capable of geometri-
cal calculation. So long az the
amount OF the change is small, and it |
has been during the period covered by
human history, no serious results
are to be apprehended but there is
no absolute certainty that the change
may not suddenly become destruct-
lively great. Such an event is i'm
probable, but not impossible. Not
only the sudden apparitiOns of new
stars, but the enormous changes of
brilliancy that many well known va
riable stars undergo, furnish evidence
of the potential capacity OF q sun to
burst forth, upon suitable ProvOca-
ton, with an overwhelming energy of
radiation, in the face of which no
planetary life could survive.
The sun is surrounded with what,
from our point OF view, might be |
termed protective envelope, or at
mosphere, which absOrbs, as the
spectroscope shows, large part of the |
radiations proceeding from the tire.
mendous inner core of the solar globe. |
Other stars possess a singular absorp- |
tive envelope, and in consequence are |
ranked in the same class with the |
IT, -, -. e
more effective in producing absOrp- |
ton than is the case with |
the sun, and such ars seem |
to be smOldering and sinking |
toward extinction, though in some |
cases they OCCASIONALLY flare up with |
furious Outbursts, as though strug-
CLING against impending fate. But |
by far the greatest mum Der of the |
stars appear to be less etfeCtuslly |
blanketed with absorbing vapOrs |
than the sun is. Sirius, for instance,
the brightest star visible to US, and |
Vega, one of the most brilliant orna-
ments of the mid summer evening s,
shine with splendor and intensity |
Of radiation far exceeding the SUMS, |
independently of the greatest size. |
Sirius, for instance, pours out seventy |
or eighty times as much light |
as the sun, although recent esti-
mates of its mass show that it is per- |
haps not more than four times as |
heavy. The intensity Of Sirious' radi. |
alton must then be many times great |
er than that of the sun, in conse-
quence of the absence of an absorptive |
atmosphere capable of stopping a |
large share of its rays. Life. bearing |
planets could not possibly circulate |
around Sirius at distances proper.
tionate to the earth's distance from |
the sun; and if the curtain that |