Evening star., 1938-11-22

Milky Way Clouds
Move Like Moons
Around Galaxy
Dr.. Gomow Soys They
Were Torn Out Of Mass
Spreading in Space
By THOMAS r. HENRY.

BY THOMAS r. HENRY.
Two satellite star clouds, revolving
around the 10000, ,0o0, ,oO0-s star Milky
Way galaxy as the moon revolves
about the earth, were described at
George Washington University last
night by DR.. George Gamow, pro-
fessor Of theoretical physics.
These titanic galactic moons"
each consisting of millions Of stars
averaging about the size of the sun,
are the two Clouds of Magellan first
observed by the Spanish explorer
and seen only in the Southern
Hemisphere.
Measurements of their distances,
DR.. Gamow said, show clearly that
they are outside the vast star con-
glomeration of which the solar sys-
tenn Is an infinitesimal part.
Light, moving at close to 100000
miles a second, requires about 5000
years to cross the great gulf of
emptiness between them and the
farthest edge of the Milky Way. It
requires 10000 years, however, to
come from the great spiral nebulae
in the constellation of Andromeda,
the next nearest object In space.
The average distance of similar OBJ
jects outside the galaxy Is 1000, 900
light years.
Torn Out Of Milky Way.
The nearness and small size of
the Clouds of Magellan, DR.. Gamow
said, together with spectroscope
observations which show that they
are moving in q roughly circular
path around the lens-shaped Milky
Way system, prove that they are
satellites torn out of the mass of
the greater star cloud in some great
catastrophe just as the moon was
torn out of the earth. This catas-
trophe may have been the close ap-
proach OF another galaxy so that it
exerted a tremendous gravitational
pull or a disbalance in the mutual
gravitational attractions between
the billions Of stars thmselves.
The two clouds of stars are not
arranged In any definite pattern.
Eventually, he explained, it NAV be
the fate of the whole galaxy to split
up into such formless masses. It
is now, he said, one member of a
family OF nine with six neighbors
besides the Clouds of Magellan
within distances of less than 100 900
light years.
Calculations based on the most
recent observations, said DR.. Ga
NOW, who is one Of the worlds fore
most mathematical physicists, show
that the whole universe represented
by millions Of galaxies scattered
through billions of light years of
space, came into existence rela-
lively very recently and is not much
older than the earth itself. Most
OF the galaxies are moving away
from each other very rapidly and
the further away tthey are the
faster they are moving. The most
remote yet observed Is about 5OO,-
100000 light years away and its
speed Of outward motion is about
one-tenth the speed OF light.
Space Expands.
The most logical explanation of
this outward motion, DR.. Gamow
said, is that it is not an actual
movement of the distant galaxies
themselves, but the expansion of the
space in which they are enclosed.
It then can be calculated from the
observed speeds that all the galaxies
must have started from approxi-
mately a common point not more
than two billion years ago. The
start of this expansion can be con-
sidered the beginning of time" it.
self, DR.. Gamow said.
In the beginning, he explained,
there must have been one unim-
aginably great, dense cloud Of gas,
probably of spherical form, which
occupied all the space that existed.
Within this mass q process started
which he calls "gravitational in
stability" Ordinarily every particle
and comglomeration of particles in
a mass exerts a gravitational attrac-
ton on every other particle so that
the whole is held together. But in
such an enormously large mass, he
said, it can be calculated that there
would be variations in the density
of different parts such that the
balance Of attractions finally would
be broken and the whole would
break up into millions Of pieces.
This, he believes, is what hap
pened. The pieces shot out, pushing
the limits of space before them as
they went, in states of rapid revolu-
tion. This resulted in the throwing
of octopus-like arms out of the
central mass Of luminous gas. The
content of these arms cooled down
and CONCEALED into the individual
stars. Eventually all of the gas goes
into such arms to form streams of
stars constantly moving past each
other.
This, DR.. Gamow said, appears to
be the present status of the Milky
Way galaxy and approximately 60
per cent of those which have been
observed. They are about halfway
along in their evolution towards a
completed star system, patternless
conglomeration of stars. About 2
per cent of the galaxies observed are
in this state.
About half the material in the
Milky Way galaxy, DR.. Gamow said,
is in the form of great clouds of dust
which blacken great CULTS of the
heavens so that no stars are visible
behind them. This dust, he be-
lieves, eventually will be pulled to-
gether into new stars so that the
Milky Way galaxy may be twice its
present size when it settles down to
enjoy ripe old age.