The Iola register. [volume] (Iola, Allen County, Kansas) 1875-1902, 1883-10-26
IMPROBABLE, But NOT IMPOSSI.
RLE.

III the Earth should Run Into Another
worid-Wonderful Stars Whose Blaze
May Have Been Caused by Coilision-Lit.
tie Danger from Comets.
The universe of space is, IN one sense.
full and crowded. EVERYWHERE our tel.
Escapes find stars; and for every one
we see there are probably hundreds. and
even thousands, too faint or small OF
far away TO reach our senses And of
this countless host of worlds not one is
at rest, but all are rushing through
space, free and unbridled, with yeloci.
ties far exceeding anything in the range
of our terrestrial experience Our swift
est cannon shot takes more than three
seconds to go a mile, but the stars and
planets seldom move slower than five
miles second, and some of them &c
two hundred. The veriest snail among
them would overhaul rifle ball in the
same sort of way that the rifle ball
would oyertake receding freight train.
Is there not, then, danger of collisions?
Have such collisions ever occurred, and,
If SO, with what consequences?
Now, in the first place, it is only in a
sense, and rather a Pickwickian one,
that space can be called crowded. True,
stars are to be seen in every direction;
but this is because our vision reaches so
unimaginably far. If we restrict our
consideration to bodies of respectable
magnitude-a hundred miles in diam
eter, for instance--we hit rather to
say that space, instead of being crowd
ed. is almost inconceivably empty. Be-
tween any star or planet and its nearest
neighbor lie usually desolate distances
of millions, or even millions of millions.
OF miles. If We assume, what is prob
ably an underestimate. that the region
commanded by our telescopes is so vast
that light takes thousand years in
coming to us from its outer confines,
and, further, that the number of its
stars is a thousand millions Qhe num-
her visible with our largest telescopes
is usually estimated at about s:xty
Inillions), then we find that the
average distance from star to
star must be about nine millions
of millions of miles. This is not quite
half the actual distance from the sun to
our nearest stellar neighbor "a Centau-
ri }, according to the received value of
Its parallaN; but it is distance which
quite deties the power of human COM
prehension. If two stars ut such dis
tance were rushing straight toward
each other with speed of ten miles 4
second, it would require nearly thirty
thousand years to bring them together.
Represent the sun, as in Sir John Her.
-schel familiar illustration, BY globe
Two feet in diameter, so that oranges,
cherries, peas and pins heads would
stanh for tho HitSnran+ -,
tances ranging from eighty feet to two
miles, then, on that scale. a Centauri
would be eight thousand miles away.
Obviously, there is plenty of elbow room
in the universe, and the chance of two
stars accidentally jostling each other is
far less than that OF the collision of two
bullets in mid-air over a battlefield.
Still the possibility remains.
There is a prevalent impression that
the immunity from collision between
the heavenly bodies depends mainly on
their being held in orderly orbits by
central attractions; and it is true that
their orbital constraints make it quite
impossible for the planets to collide
with each other, or even to- approach
each other very closely. But a very
impressive picture is sometimes drawn
of what would happen if the earth, for
instance, should sometime free herself
from the bonds of gravitation-how she
would fly off into space (Which is true.
of course). and soon dash herself to
pieces against some other wandering
world (Which is not true at all. or
at least not probabie). Most likely, if
graviiation were suddenly to cease, the
earth would travel for millions, not of
years, but of ages, without ever en-
-countering anything more important
than meteors, such as are now contn-
ually falling upon her surface. And
these metcoric encounters, even, would
probably be far less frequent than at
present, since there is reason to suppose
that such bodies are much more nu-
merous in the neighborhood of the sun.
and of other great stars than in the rest
of space.
Evidently, however, the attractions
between a wandering star and others
lying near its path must considerably
increase the chances of collision, though.
not to so great an extent as perhaps
might be supposed. A body entering
our system at distance from the sun
-one hundred times as great as the
radios OF the earth's orbit, and moving
with no more than the velocity natural |
TO comet at that distance (about 2s i
miles per second), would not strike the |
sun unless its path We're directed within |
Hess than half degree (23.4 sec.) of
the sun center; and if its velocity |
were greater. the aim would have to be |
still more accurate to score a hit IL |
bodies were shot into space at random |
from the position and with the velocity |
indicated, only about one in e;ghty-six |
thousand would hit the sun. Were il |
not for the suns attraction. however. |
the proportion would be twenty thou |
sand times smaller still-only one in
seventeen hundred millions.
1t is obvious, therefore, that encount-
ers between heavenly bodies Of consider
able magnitude must be extremely rare.
There is not in all the astronomical
record a single certain instance of such
an occurrence. And yet il may conf
IDENTIFY be asserted that some time or
other in the past such events musA have
happened, and some time in the future
will happen again, simply for the rea-
son that, in sufficient length of time,
the most improbable things, if only not
impossible, are sure to come to pass.
Now, il IS almost certain that the stellar
motions are not such as to render col
ilsions impossible; the planets. it is true,
as has been said before, can never run
into each other, because of the size and
nature OF their orbits. but, so far as can
now De aseertained, nothing of the sort
holds good for the motions of the stars.