Evening star., 1954-12-17
Millions of Big Stors
Scattered in Galaxy
Supereionts Are 1000
Times Brighter Than Sun

Supergiant stars from $4,000 TO
100000 times brighter than the sun
are landmarks in the greater Cloud
of Magellan, visible in the Southern
Hemisphere.
This has just been reported to the
National Academy Of Sciences by Drs.
Harlow Shapley and Virginia NJ. Nail
of Harvard. The two Clouds Of Magsl-
Ian. one considerably smaller than the
other, are known to be aggregations
of millions of stars Of all sorts situated
over q vast gulf of empty space from
the million -billion-star Milky Way
galaxy Of which the solar system is
part.
They are, however, the nearest OF
the galaxies, or other universeS. and
belong, together with the Milky Way
system, among eight or ten located IN
this neighborhood of space. Within
both, despite the enormous distance, 1t
is not difficult to distinguish individual
bright stars. Both are quite small gall
axies, compared with our own or most
of the others in the local group.
10000 Light Years.
Light from the large cloud at q
speed of about 10000 miles second
requires 10000 years to reach the
earth, DR.. Shapley pointed out. The
nearest galaxy beyond is at distance
of more than TOO. 900 light years.
The Harvard astronomers have been
concentrating on the large cloud in
order to learn something of the "anat-
omy of galaxies." This is impossible
e. Nuox
tenn is concerned for the forest is
hidden by the trees" More closely
parallel galaxies are too far away.
The supergiant stars are among the
more notable findings. Dr.. Shapley said.
and apparently represent something
unknown in the Milky Way system.
Some of these are reddish in color.
vary somewhat in brightness from time
to time, and have an average radiation
$4,000 times that of the sun. These
are Pickering candles, however, COM
pared with the supergiant blues, ap-
parently extremely hot from their color.
which emit constantly about 100000
times the suns radiation.
Around the borders of the Milky Way
system are the so-called globular clus-
ters. They belong to the system and
their movements are controlled by 1t,
although they are at vast distance
from its center. Each of these clusters.
it has been determined. consists of
tens of thousands of all sorts Of stars.
some giants and the majority ordinary
celestial objects such as the sun. Yet
when distance is taken into considera-
ton. DR.. Shapley said, none of these
he
of single great blue stars in the large
cloud.
This galaxy seems peculiar sort,
the Harvard astronomer pointed out.
The majority of those now known are
so-called "spirals," with arms of stars
around central nucleus, like the spring
of a watch This is the form Of the
Milky Way galaxy, which seems quite
typical.
No Nucleus.
The large cloud seems to have no
nucleus. Instead. the telescope reveals,
a thick bar of stars runs through its
center. Scattered along this bar DR..
Shapley and his associates have identi-
fed more than 800 of the type of stars
known as cepheid variableS, whose lu-
minosity goes up and down in regular
periods. Within the Milky Way system.
it has been determined, the length OF
these periods varies with the intrinsic
brightness of the star. Thus the
cepheids are the most commonly used
"yardsticks of the heavens" for the
determination of vast distances. The
variables in the large cloud seem to
follow the same schedules. They are
throwing much light on the structure
of the galaxy.
Further light on the anatomy of the
great star aggregation, DR.. Shapley said.
is expected when the great radio tele-
scopes now set up in Australia are able
to detect radio waves from clouds OF
hydrogen gas which surround the gal
axy and also probably are TO be found
inside it.