Evening star., 1934-07-29
BY THOMAS r. HENRY.

universe.
There may be literally billions of
planets like the earth capable of sup
porting life.
This radical position is taken by
two leading astronomers this week,
both advancing entirely different hy-
pothesis to support their contentious.
OF late years astronomers have held,
almost without exception, that this
solar system was one of the very few
in creation and possibly UNIQUE. They
based their contention on the hypo-
thesis that it was formed by the col
lision Of the sun and some passing
star, with the result that part of the
suns substance was torn loose and
distributed in orbits around 1t. The
new hypothesis show at least two
other ways in which it might have
happened.
Whether other stars have planets
is impossible of observational verifica-
ton. The most powerful telescope
imaginable could not detect the
largest planet Of the nearest star.
Hypothesis Is Advanced
BY DIR. Gustaf Stromberg.
The first of these new hypotheses
Is advanced by DR.. Gustaf StromEerg
of the staff of the Carnegie Insti-
tuition of Washington. 1t makes the
formation of planetary system a
special case of the same series of
phenomena which may be responsible
for the present structure of the uni
verse itself.
He goes back to the day of immense
masses of gas, no further apart than
their own diameters and pulled in
various directions by their attrac-
tions upon each other. They were
the beginnings of the spiral nebu-
lac" of today--one Of which is the
Milky Way system. of which most
visible stars are part. There were
no stars then-just loose particles of
gas.
These monStrouS gas clouds fire.
quently bumped into each other"
with the result that they were given
circular motions. Then, with the
complicated interactionS Of gravity,
centrifugal force and the increasing
viscosity. or "stickiness," of the gas
toward the center Of revolving cloud,
the particles began to conglomerate
into masses. These masses would be
thicker, bigger and denser toward the
center of a gas cloud. The smaller
and lighter ones would be formed
toward the borders.
This is approximately the picture
actually obtained of galactic system.
DR.. StrOmberg argues that, at a later
stage planetary system would be
formed in the same way, for each
star in the beginning is a small model
r the whole galactic system of which
1t forms a part.
Every star in its early stage of
development" he says, must be sur
rounded by a huge atmosphere in
which, under proper conditions, smaller
condensations may be formed. These
would. at later stage, be identified
with planets moving in circles about
the sun. At a very early stage in the
development OF stars encounters of
the type here considered were prob
ably rather frequent. AS a conse-
quence planetary systems like the sun
would be fairly frequent"
X
Same Conclusion Reached
BY Prof Dinsmore Alter.
The same conclusion is reached
from an entirely different starting
point by Prof. DinSmore Alter Of the
University of Kansas.
His starting point is the sun itself
ATn = nK-Nn nd
hotter than at present. 1t had an
immense radiation pressure" which
was shooting vast quantities OF atoms
into space around it. When these got
far enough away. with constantly
decreasing velocities, the attraction
tending to draw them together became
sufficient to overcome the speed OF
outward motion tending to keep them
apart. Finally collection zone was
/ reached. A few atoms would combine.
Such a combination attracted more
atoms until finally a body of planetary
size was reached.
This body, in turn. would exert q
tidal force on the sun, pulling more
and more of its substance into space.
But in the meantime the radiation
push Of the parent body would have
| decreased with the loss Of heat. 1t
would be shooting out the atoms with
| less force The collecting zone
would be moved nearer. There
another planet would BE- formed,
bigger than the first one because Of
the greater amount OF material
brought out by the tidal pull.
Then the process would be re-
peated stiu larger planet would
| De formed still nearer the sun. Thus
| Il would continue until the decrease
| Of the suns radiation pressure had
| reached a critical point where the
amount Of particles it was able 70
shoot out began to decrease. Then
| the new planets would grow smaller.
This is almost precisely the pic
ture actually presented by the solar
system-an increase IN size from Nep-