Evening star., 1936-12-09

by very large distances of the order
OF tens Of millions of times the di-
ameter of star.
Our sun is member of one OF
these galaxies-the Milky Way. 1t
Is known from star counts in various
directions that the Milky Way or gall
axy Is roughly lens shaped. with a
diameter of perhaps 100,0 900 light years
and a maximum thickness Of some
thing like one-fifth to one-tenth Of
this. The sun Is at a considerable
distance from the center but not very
far from the median plane of the
system. Knowing the distances and
directions of other galaxies, it be-
comes possible to construct a scale
model Of that part of the universe
about which We are best informed.
Galaxies in Cluster.
"These neighbors. together with our
Milky Way, appear to constitute a
small cluster of galaXies, IL in num-
ber, the individuals of which are
considerably nearer together than is
the rule in the surrounding space;
in fact a moderate gap appears to
exist between this group snd the other
nearby systems. Studies of the de-
tails of nearby systems help us under
stand distant systems and especially
our own system, while studies of our
own system clear up problems which
arise in the study of our neighbors.
The conclusion follows that almost
our entire success in the exploration
Of extra-galactic space has been due
to the fortunate circumstance that our
own galaxy is member of small
group or cluster of galaxies
The new knowledge about absorb
ing material in the spaces Of our
GALAXY has contributed to this pic
ture Of the local group of nebulae, and
Of the universe as a whole, princi-
pally by reducing the inferred i'm
portance of our own system. At one
time the Milky Way system was con-
sidered large enough to contain all
the nebulae. When these were de-
termined TO be independent external
systems Of stars, the Milky Way still
held the predominant place, being
thought to be perhaps five times as
large in diameter as the next largest
similar system. With the dimensions
OF our own galaxy revised on the basis
Of absorption to about half the previ-
GUS size, and the diameters Of other
galaxies found to be larger than were
formerly measured, our own place in
space Is not nearly so unique as We
formerly had good reason to believe"
This picture of the universe is the
result Of observations Of spiral nebulae
with the 100-inch telescope at the
Mount Wilson Observatory of the Car
negie Institution of Washington, with
which it is possible to penetrate about
500, 100000 light years Of space.
New Fields for Telescope.
.Somtime in 1910, if all goes well, it
may be possible to "see' twice as far
approximately 100000, ,000, ,0o0, ,O00,-
100000 miles-and at events which
we're happening 1,000,000,000 years
ego. Such is the theoretical possi-
bility of the new 200-inch telescope
weight TOO tons, cost $4,000 ,00o-which
now is being set up on Mount Palo-
mar, near Pasadena, Calf, in a CO.
operative project of the Rockefeller
Foundation, the Carnegie Institution
Of Washington and the California In
stitute Of Technology.
Progress made to date in the prof.
ect was described in lecture before
the Carnegie Institution here last
night by DR.. John A. Anderson. ply
sicist of the Carnegie staff, who has
been the executive officer and taken
. leading part in the planning and
construction of the titanic eye.
The night the great telescope is
first trained on the sky is likely to be
O notable date in history, for then 1t
will be possible to look twice as far
and see eight times as much Of crea-
ton as has been possible in the past