Evening star., 1951-10-22
Big Mt. PuIomor Lens
Probes Stor's S Spectre
Chemistry of NebuIue Nay
Answer Some Busic Problems
By Thomas R. Henry

Chemistry of the far-flung planetary
nebulae, which may give answers to
some fundamental problems of the
universe, now is being investigated with
the 200-inch telescope, largest in the
world, on Mount Palomar, Calf.
These objects are extremely rarefied
clouds Of gas surrounding, in every case,
a very hot star from which presumably
the gas has been elected. They belong
to the Milky Way system, thus being dis
tinguished from the extra -galactic nebu-
lac which are of comparable size to the
Milky Way itself. are far distant in space,
and constitute separate 'universeS."
The question of the chemical COM
position of stars, it is emphasized by
DR.. Ira S. Bowen, director of the Mount
Palomar Observatory, operated jointly
by the California Institute of Technology
and the Carnegie Institution of WASH
ington, is of increasing practical signifi-
canoe because of the advances in nuclear
physics of the so-called atomic age.
Transformation of Hydrogen.
I'VE already know" DR.. Bowen says,
''that the energy radiated by the sun
and most of the stars comes from the
transformation of hydrogen into helium
in their very hot cores. (This is the
mechanism Of the proposed H bomb)
But none of the mechanisms now in OPP
Grafton in the stellar interiors provides
a means for creating the heavier ele-
ments. It is therefore of interest to
know whether all stars have the same
relative abundance Of these heavier ele-
ments. Determination Of this may throw
light on their origin"
A substantial number Of exposures,
often of several nights duration. already
have been taken of the spectra of group
of planetary nebulae. These spectra are
being used for the study Of the chemical
composition of the gases and for an
analysis of the internal motions of the
gaseous envelopes. From such studies it
may be possible to determine points at
which the heavier elements make their
appearance.
Attention of the Mount Palomar as
tronomers also is being concentrated on
a type of stars known as "long- period
red variables" These are large, relative
ly cool stars, the intensity of whose light
undergoes considerable variation over
periods of years. In the past fairly salts
factory spectra have been obtained when
these stars were at their maximum of
brightness. With the new telescope SINH
lar information can be obtained when
they are at the minimum. Thus it will
be possible to determine changes in the
distribution of elements as star wanes
and wakes.
Quest of Basic Material.
The major work of the observatory.
however, remains that Of determining
the physical structure of the universe
itself through study Of the distribution
of the extra-galactic nebulae. the aggre-
cations Of billions of stars comparable
to the Milky Way galaxy which lie in far
depths of space. These appear to be NOV
ing outwards from the position Of the
earth at speeds which increase with dis
tance, giving rise to the theory of an ex-
ploding universe. Already with the new
telescope. it is announced through the
National Geographic Society which is
cooperating in the survey Of the far
heavens Dr. Milton L. Humanson of the
Mount Palomar staff has found objects
moving outwards at speed one-fifth
that of light. or approximately 10000
miles second.