Evening star., 1951-05-23
Milky Way Galaxy Seen
Like Spring of q Watch
Observations at U. Of Virginia
Show Winding or Unwinding
By Thomos R. Henry


The Milky Way galaxy Is like the
spring Of q watch.
Is it unwinding or winding up around
the forever invisible nucleus, somewhere
in the direction Of the constellation Of
Sagittarius in the northern heavens?
This is a problem on which DR.. A. N.
Vyssotsky, astronomer Of the Leander
Mccormick observatory Of the Univer-
sity Of Virginia. now is throwing some
light by nightly observations from
mountain top near Charlottesville.
He is not yet able to give definite
answer, because the problem gets more
and more complicated as the number
of observations increase. The McCor-
mick observatory astronomers. however.
have fixed rather definitely the position
of the sun and It's planets near the outer
edge Of one OF the spiral arms of the
snake-like coil about 10000 light years
from the invisible center.
Dust Hinders Studies.
The galaxy OF about hundred billion
stars, of which the sun Is a fairly aver
age example, is about 100 900 light years
in diameter. Its center, presumably
closely packed aggregation of stars, is
closed to observation because Of an enor-
nous dust cloud through which little
light penetrates, making impossible the
observation of individual objects. There
are thinner aggregationS Of dust, inter-
spersed with relatively few stars, be-
tween the arms of the spiral. This makes
inescapable the conclusion that the stars
are arranged in coil, instead Of being
distributed uniformly through galactic
space.
This picture Of the galaxy as a spiral
is relatively recent. It is based primarily
on the appearance Of the nearest ex-
ternal galaxieS, close to million light
years distant, which are Of about the
same size. They are too far away to
observe the direction Of motion OF In
dividual stars within their arms.
It has long been recognized that the
sun and its system Of planets Is not far
from the outer edge Of the galaxy. In
the direction away from the invisible
center there the stars thin out rapidly
to ring of clusters Of stars, like the
edge Of a watch casing, which apparently
are not part Of the spiral itself.
For many years the University Of
Virginia astronomers have been en-
gagged in an intensive study Of relatively
nearby stars-that is objects within q
distance Of 10 to Is light years and
bright enough to be visible with the
Mccormick observatory telescope. II
there could be a precise determination
Of the direction in which this local
system 1s moving. the determination Of
whether the watch Of the heavens il
running down or being wound up would
be relatively simple.
Motion All Of Its Own.
But unfortunately, it seems. this
system has a motion all its own which
is quite apart from the spiral motion.
1t also Is revolving around q center.
Within this rotation there are still other
movements. such as the revolution Of
the planets around the sun and the
complex movements Of the sun itself.
The object of DR.. Vyssotsky's obser-
vations is to determine the peculiar
motions of the sun itself and then SUBJ
tract them from the revolution Of the
local system. Then it will be possible
to determine the direction of the sys-
TENS motion within the spiral arm Of
which it forms a part.
On the solution Of this problem de-
pends an accurate picture Of the fate
of the universe and its age, on which
there now is wide disagreement. The
preponderance Of evidence is that the
Milky Way galaxy is winding up around
the center-a process which presumably
would require billion years or more.
But. it is pointed out. there are some
observations which seem to indicate
a directly opposite direction Of move
ment.