Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1883-10-26
Astrono 0 nj al Collisions.

There is prevalent impression writes
Prof. Young in the North Anlerican Re
VieU, that the immunity from collision
between the heavenly bodies depends
mainly on their being held in orderly or
bits by central action and it is true that
their orbital restraints make it quite i'm
possible for the planets to collide with
each other, or even to approach each 9TH
er very closely. But very impressive
picture is sometimes drawn of what would
happen if the earth, for instance, should
some time 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 probable.) Most likely, if
gravitation were suddenly to cease, the
earth would travel for millions, not of
years but OF ages, without ever encoun-
tering anything moro important than me-
teors, such as are now continually fall
ing upon her surface. And these meteor
ic encounters even, would probably be
far less frequent than at present, sine,
there is reason to suppose that such bod
les are much more numerous in the neigh
borhood OF the sun and of other great
stars than in the rest Of space. Evident
ly, however, the attractions between n
wandering star and others lying near its
path must considerably increase the
chances of collision, thought not to so
great an extent as perhaps might be sup
posed. A body entering our system at a
distance from the sun 100 times rs great
as the radius of the carth's orbit, and
moving with no more than the velocity
| N at ttrn1 t. IN Of - thot 1iutnnnn Ial
two and two-third miles per second, J
would not strike the sun unless its path
We're directed within less than half de-
gree (23. .4) of the suns centre and if its
velocity wele greater, the aim would have
to be still more accurate to score hit.
If bodies were shot into space at random
from the position and with the velocity
indicated, only about one in eighty. six
thousand woul,l hit the sun. Were it not
for the suns attratIon, however, the pro-
portion would be twenty thousand times
smaller still-only one in seventeen hun
dred millions. 1t is obvious, therefore,
that encounters between heavenly bodies
of considerable magnitude must be cx-
tremely rare. There is not in all the as
of such au occurrence. And yet it may
Dc ubotItttl llltt illllt OT
other in the past such events must have
happened, and some time in the future
will happen again, simply for the reason
that, in n sufficient length of time, the
most improbable things, if only not i'm.
possible are sure to come to pass. Now,
it is almost certain that the stellar mo.
tions are not such as to render collisions
impossible +; the planets, it is true, as has
been said before, can never run into eacL
other, because Of the size and nature OF
their orbits, but, SO far as can now be as.
certained, nothing of the sort holds good
for the motions of the stars. We already
know enough about some of their social
ed proper motions" to bequite sure that
as fact, they are not travelling in any
simple curves, around any common cen
tire, and also that some stars are flying
through space with such velocites that nc
attraction, such as can reasonablybe sup
posed to act i'll the premises, can contro
them. Nor does theory, any more thar
observation, indicate structure of the
stellar universe at all analogous to that o.
the planetary system. Among the stari
there is no central dominance and no i'm
perial power, but we have to do with
republic of comparatively free and indie
pendent members