Evening star., 1947-04-28
e
The sun has a weekly heartbeat.


The sun has a weekly heartbeat.
Once every 66456 days, precisely
its radiation of heat and light into
space, upon which the life of the
earth depends, ebbs or rises by ap-
proximately one two-hundredth part
This heartbeat, which may play a
vital role in various physical phe-
nomena on earth, is so feeble that
it never has been observed before.
The discovery was reported to the
National Academy of Sciences,
meeting here today, by DR.. Charles
G. Abbot, former secretary of the
Smithsonian Institution. It resulted
from an intensive statistical analy-
sis of measurements of daily varia-
tions in solar radiation for IS years
made at the Smithsonian Observa-
tory on the summit of Mount Mon
tezuma in Chile.
The heart beat, DR.. Abbot says, is
reflected in temperatures on earth
and may eventually prove of value
in weather forecasting, although the
mechanism of the reflection is ex-
tremely complicated. The time
period of temperature fluctuations is
almost precisely the same, but is not
necessarily parallel in time. =
In Class by Itself.
This radiation fuctuation places
the sun in class entirely by itself
he explained, and the necessary
observations are so delicate that it
probably never will be possible to
find out whether any other stars
behave in the same way. Many
variable stars are known in the
Milky Way system. All of them are
from 100 to 100000 times brighter
than the sun and their fluctuations
are relatively enormous, so that they
easily can be observed from the
earth. The variations are known to
be due to expansions and contrac-
tions in the orbs of the stars them
selves, like the rising and falling of
the chest in breathing.
This explanation, DR.. Abbot said
is impossible for the solar heart
beat
The temperature effects on earth,
as shown by United States Weather
Bureau records, often are quite pro-
nounced, he explained and cannot
be accounted or by actual increases
or decreases in the heat received
from the sun. -
The earth. however, is surrounded
by continuous sheet of the rare
gas, ozone, form of oxygen, at an
altitude of about 40 miles. 1t plays
an important part in shielding the
surface from the deadly ultraviolet
radiation of the sun and in keeping
the heat of the earth itself from
being radiated into outer space. The
thickness of this ozone layer, how
ever, is largely determined by the
amount of the solar radiation OF
invisible ultraviolet light.
Cosmic Ray Storms Aid Study.
The most probable hypothesis is
that the apparently minute varia-
tons due to the suns heartbeat are
quite large in the ultraviolet region
OF the suns spectrum with corre-
spondingly great effects on the
ozone layer. This would account for
the temperature differences but
science has 10 way now of knowing
whether it actually happens.
Three great cosmic ray storms in
the past 10 years. each of which
lasted several hours and we're cb-
served simultaneously in different
parts of the earth except at the
equator, may serve as the basis for
IA new theory of the origin CT these
mysterious radiatiens. reaching in
ltensities of several billion or more
Ielectron volts, which lombard the
earth from outer space, the academy
was told by DR.. Scott e. Forbusi1
of the Carnegie Institution of Wash
ington.
Each Of these storms was accom-