The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1926-04-14
SUNS RELATION
TO WEATHER is
BEING Sol. we'd
Astronomers Find Chief
FIuctuation Lies in
Violet Rays.
By David DietZ,
NEA tSerUfce Writer

MT. WILSON, Cal, April H.
A discovery just made at the Mt.
Wilson observatory here may prove
to be one OF the most important
facts so far brought to light in
helping scientists solve the puzzle
Of the connection between the sun
and the weather.
1t had been previously pointed out
through the work Of Dr. c. G. Alb
bot that the amount Of energy sent
out by the sun varied from day to
day. And it has been assumed that
the ultimate cause Of fluctuations
in the weather must lie in these
fluctuations.
The problem, however, is to dis
cover just what the connection IS
and how it works.
Now, DR.. Edison Petit Of the Mt.
Wilson observatory here has made
an important advance in the attack
on this problem by showing that
the chief fluctuation in the energy
radiated by the sun lies in the in
visible but highly active ultraviolet
rays.
Two observing stations, one In
California ana one in Chile, OPP
Grated by the Smithsonian Institu-
ton under the general direction OF
DR.. Abbot, measure the total amount
of energy radiated by the sun, heat
or infra-red rays, light rays and
ultraviolet rays. DR.. Abbot is now
IL I'll 70 c.te
ton to do similar work.
DR.. Petit arranged his apparatus.
however, so that it would measure
only certain definite parts OF the
suns energy.
He covered a telescope lens with
a thin gold film. AS a result only
the green light of the sun came
through it. Then he focused this
light on a thermocouple, a device
for measuring energy, and connected
that to a recording instrument. Next
he arranged a quartz lens covered
with a thin silver film. This has
the property of allowing only the
ultraviolet light to get through. This
was measured and recorded in the
same way.
THE records show that the green
light from the sun is practically con-
slant from day to day." DIR. Petit
told me. "On the other hand, they
show violent fluctuations in the
ultraviolet light
From June, 1924, to November,
1925. the amount of ultraviolet light
given off by the sun increased SO
per cent. Then from November to
December, 1t fell off 20 per cent. 1t
has remained in tho neighborhood
of the December figure since But
there are constant daily fluctuations
in the amount of ultra violet light.
Now DR.. Abbot has found that
the total amount Of energy given off
by the sun varies from day to day.
1t must be therefore, that this vari-
alton Is due to the fluctuations in
the ultraviolet light"
This discovery Of DR.. Pettit's is an
important clew for meteorologists
who hope to learn the connection
between the sun and the weather. 1t
means, Of course, that it is highly
important that work be done to find
out just what effect the ultraviolet
radiation of the sun has on the earth
and it's atmosphere.
DR.. Pettit's work is part Of a. gen-
eral program for studying the sun
at Mt. Wilson. This program is the
most extensive in the world.
The Mt. Wilson astronomers feel
that before the connection between
the sun and the weather can be
worked out, we must know about
the sun itself. Consequently, they
are centering their attention on the
sun.
DIR. George r. Hale, honorary dI-
rector Of the observatory; DR..
Charles e. st. John, president of
the solar section Of the international
Astronomical Union, and other
members of the staff, are devoting
their chief energies to this task
There are many problems, to be-
solved yet. For example, the corona
or silvery halo about the sun which
becomes visible at the time of to-
tai eclipse, is still a mystery to as
tronomers. Connections between the
shape OF the corona and the number
of spots on the sun have been noted,
but the exact cause and nature OF
the corona is still unknown.