270 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1959 
lite perturbations unquestionably related to the 27-day solar rotation, 
to specific solar flares, and to geomagnetic activity. 
The sun—tThe sun, generator and moderator of the physical forces 
affecting the earth, became a primary focus of attention. More than 
100 patrols maintained watch upon it nearly every minute of the IGY, 
and 30 or more observatories, including 7 in the United States, photo- 
graphed the sun at 3-minute intervals, comprising in effect an unprece- 
dented motion-picture study. A notable achievement was the new 
order of fineness achieved in the photography of the granulation of 
the sun’s surface, employing a combination of telescope and automatic 
sun pointer from a balloon at 80,000 feet. Thus we have the most 
detailed solar record in history, and for the first time an almost com- 
plete record of hydrogen gas flares, the influence of which upon the 
earth’s ionosphere ranks among the most dramatic events in solar- 
terrestrial relationships. Sudden effects, caused by the bursts of 
ultraviolet light and soft X-rays, are seen in magnetic recordings, 
fadeouts of shortwave radio, enhancement of atmospherics (radio 
static), and reductions in cosmic radio noise level. 
The sun cooperated notably by achieving the highest level of activity 
ever known. On Christmas Day of 1957 the greatest number of sun- 
spots occurred since Galileo first reported them in 1612. Flares 
abounded. From this fabulous record a drastically modified concept 
of sun-earth relationships and of the conditions of interplanetary 
space has been derived. 
Many sources of solar radiation were identified. Remarkably fine 
and detailed photographs showed the ultraviolet ight source to be in 
patches closely associated with calcium plages (flocculi or clouds). 
Solar hydrogen flares are identified as a source of gamma radiation. 
Radio emissions of thermal generation were confirmed from coronal 
regions at much lower temperatures than previously believed possible. 
Radio noise emissions, noted to be associated with optical flares and 
energetic proton flux, await full explanation. Balloon measurements 
during eclipses have indicated the corona to be the source of X-rays, 
possibly an important factor in the causes of radio blackouts—the 
most widely known and troublesome of solar effects. Strong X-ray 
flux was discovered at 60,000 to 90,000 feet during auroral displays 
accompanying ionospheric disturbances. 
The magnetic fields of the sun are perhaps the most important prob- 
lem in solar physics, since therein can be found the forces that acceler- 
ate the solar particles affecting space and our upper atmosphere. A 
main magnetic field of minor intensity exists, with the property of 
puzzling polarity reversals that are presumed to be associated with 
the dynamic conditions of solar material. Intense local fields accom- 
pany sunspots and flares, and correlations between changes of field 
