Evening star., 1939-05-06
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BY Thomas r. Henri.

TI0 Sso0y .,.5
BY Thomas r. Henry.
A new fundamental time division-the
1896 year sunspot cycle-has Just been
introduced by H. Helm Clayton, Smith
sonian Institution collaboration, in q re-
port on mathematical analysis of solar
activity just issued by the institution.
BY means Of it, Mr.. Clayton shows, he
can make fairly accurate predictions not
only Of the times Of recurrence Of maxi
mum and minimum numbers Of these
titanic whirlwinds in the suns atmo-
sphere Of fire, but also their amplitude at
different occurrences.
The great cycle in turn is split into
eight component cycles. These might be
likened to eight seasons" on the sun, due
to some unknown factors in its own
physical constitution. Sunspots are at
tracing constantly more and more at
tention because of their known and sus-
pected correlations with conditions on
earth. They are known to effect the
earth's magnetic field, and consequently
radio transmission. They are strongly
suspected Of exercising q dominant in
huence over weather.
Up to the present, however, means Of
predicting them have been quite unsat-
isfactory. 1t has long been known that
there is a basic sunspot cycle, during
which the spots increase from minimum
to maximum numbers and back to mini
mum again, which repeats itself approxi-
mately every " years. This, however, is
only an average. In the past $50 years
it has been as short as years and as
long as 13 years. Nobody has been able
to predict with any confidence when
cycle would repeat itself.
1t also has been impossible to predict
very accurately the amplitude OF either
minima or maxima. At some of the II.
year occurrences the sun has been far
stormier than at others. 1t has lust
passed through one of the most tempes-
tuous periods known since sunspots have
been under observation and now is on its
way back toward fair weather" once
more.
The trouble has been that the 11-year
cycle is just an approximation. 1t is
made up, as has been demonstrated sew
eral times in the past and notably
through the researches of DR.. Charles G.
Abbot, secretary of the Smithsonian In
stitution, of several constituent cycles
The maxima and minima Of several Of
these cycles tend to come together ap-
proximately every II years. These minor
cycles are Of varying length and am
plitude. They appear at first to be mex
tricably confused. The minimum of one
may occur at the maximum of another,
reducing its normal amplitude. Or two
or more maxima may occur together,
raising the amplitude far above normal
The problem has been first to compute
the normal lengths and amplitudes of
these cycles and then determine the
points of their concurrences.
This has involved very laborious sta
tistical procedures. Mr.. Clayton has
analyzed the yearly sunspot data since
1893, or as long as entirely reliable rec
ords have been kept. He finds a con-
slant recurrence Of eight cycles-one OF
which Is the basic period which he recall
culates at almost precisely 11.17 years.
The others are 556. 812, 894, 993, IL,
1489 and 1886 years, respectively. All
are very nearly submultiples Of the
fundamental period of 1886 years, a
period in which all their concurrences
will have taken place. This, then, be-
comes the major sunspot period, and the
one upon which predictions must be
based.
Mr.. Clayton tested the predictive VAL
ue of his work by projecting his theo-
retical sunSpot curve forward from 1880,
and comparing it with the actual maxi
ma and minima and their amplitudes.
Except for one maximum, that of 1928 it
fitted almost perfectly. Projected into
the future it shows that the sun already
Is on its way toward sunspot minimum
to be expected about 1945, after which it
will rise to a new maximum. but
slightly lower one than that through
which the solar system has just passed,
in 1949.
There is still the possibility, Mr.. Clay.
ton points out, OF uncovering new perio-
dicities in the complex statistical tangle
and these would be expected to bring
the theoretical curve closer to the actual
one. 1t is all convincing evidence, he be-
lieves, that these solar tempests cannot
be considered as irregular explosions in
the sun occurring with a randomness
which cannot be predicted, but that their
frequency is governed by definite laws,
however complex these may be.
Mr.. Clayton also advances some tenta-
tive correlations between solar activity
and atmospheric pressure, particularly in
high latitudes.
poCSo ~