Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1882-08-23
THE BoUEDARIgs OF ASTRONOMY.

The star sweeps along through our sys-
tenn with stupendous velocity. Now there
can be no doubt that if the star were per-
manently to retain this velocity it would
IN the course of time travel right across our
system, and, after leaving our system,
would retreat into the depths of infinite
space. Is there any power adequate to re.
call this star from the voyage to infinity
We know of none, unless it be the atlrac-
ton Of the stars or other bodies of our
sidereal system. It therefore becomes Q
matter OF calculation to determine whether
the attraction of all the material bodies of
our sidereal system could be adequate, even
with universal gravitation, to recall body
winch seems bent ON leaving that system
with velocity of ECO miles per second.
Ihls interesting problem has been discussed
by Professor NeNcomb, whose calcu-
latlons We shall here follow. In
the hrst place, we require to make
some estimates of the dimensions
OF the sidereal system, in order
To see whether it seems likely that this
star can ever be recalled. The number of
stars may be taken at 100, DOC, 900, which
is PROBABLY double as many as the number
we can zee with our beat telescopes. The
masses OF the stars may be taken as on
the average five times as great as the MAS
OF the Gun. The distribution of the stars
is suggested by the constitution of the
milky way One hundred million stars
are presumed to be disposed in fat circu-
lar layer OF zach dimensions that ray of
hgDt woald require 30, 900 years to ira.
verse one diameter. Assuming the ordi-
nary law OF Grar-tslioc, 1t is now easy to
compute the efficiency OF such an arrange.
ment IN attempting to recall moving star.
Inc Wnoie question turns on certain crit.
cal velocity OF % miles second. Ii star
darted through The system we have
Just been considering with a velocity less
than twenty-five miles a second, then,
after thas star had moved for GER
tam distance, the attractive power of
the system would gradually bend the
path OF the star round, and force the star
to return to the system. If, therefore. the
yelocltles CT the stars were under no cir
cumstances more than 25 miles second,
then, supposing the system to have the
character we have described, that system
might be always the same. The stars
might be in incessant motion, but they
must always remain in the vicinity of our
present system: and our whole sidereal
system might be an isolated object
IN space, just as our solar system is an
isolated object in the extent of the
sldereal system, We have, however, seen
that for one star at all events the
velocity Is no lees than 200 miles second.
II this star dash through the system,
then the attractions of all the bodies
IN the system will unite in one
grand effort to recall the wanderer.
This attraction must, to some extent,
be Acknowledged the speed of the
wanderer must gradually diminish as
he recedes into space but that
speed will never be lessened sufficiently to
bring the star back again. As the star re-
treats further and further, the potency of
the attraction will decrease, hut, owing to
the velocity of the star being over % miles
a second, the attraction can never over.
come the velocity; so that the star seems
destined to escape. This calculation is,
of course, founded on our assumption as to
the total mass of the stars and other bodies
which form our siGereal system. That
was founded on a liberal, indeed a
very liberal, Interpretation OF the evidence
which our telescopes have afforded. But
Il may still fall short of the truth. There
may be more than hundred million stars
u cnr system their AVERAGE weight may
be more than five times the weight
OF our sun. But unless the assumption we
have made is enormously short of the truth,
cur inference cannot be challenged. -TProf.
Ball In the Contemporary Review.