CORONA OF THE SUN

New Zealand Herald, Volume LXXI, Issue 21698, 13 January 1934, Page 7 (Supplement)

CORONA OF THE SUN

BIG PROPORTION OF OXYGEN The sun's corona is largely oxygen. Perhaps the most important astronomical discovery in recent years was announced from the research laboratories of the Harvard Observatory. Coronium is the term which has been used for the last 60 years for explaining the pearly whiteness of the sun's corona, visible only during a total eclipse, says the Christian Science Monitor. More than a year has passed since the last total eclipse, and the first information of major importance was announced when Dr. Donald H. Menzel, of Harvard, and Dr. Joseph C. Boyce, of Massachusetts Institute of Technology, made known that the element most prominent in the corona, previously called coronium for want of knowledge as to its exact nature, is oxygen.

The nnouncement of the discovery was made on a regulation observatory announcement card, the brief technical paragraph scarcely portraying the excitement and enthusiasm displayed by observatory officials. For a long time astronomers have sought to learn the nature of the corona. It was previously believed to be made up of some element not known on earth, causing the mysterious pearly light only about one-half as bright as that of full moon. The sun's corona has been photographed as extending more than 10,000,000 miles beyond the surface, and gravity is computed to be 27 times more powerful on the sun than it is on the earth. If the oxygen which makes up the corona were atmospheric in nature, the resulting pressure would be unthinkable. Though this is viewed as a great step forward, there are still many problems to be solved.

Dr. Menzel and Dr. Boyce have found that " analysis of the coronal spectrum reveals that the frequency difference between coronal lines agrees with the difference between two known high energy states of the neutral oxygen atom, which suggests that the lines are produced by combination with a higher energy state." Interpreting the announcement, it is noted that Dr. Menzel and Dr. Boyce have made the first important step in the unravelling of an astronomical mystery that has existed since the first observations of the corona spectra more than 60 years ago.

The radiations from the corona have been attributed to coronium much as the light of nebulae was long attributed to the hypothetical " nebulium." A few years ago this was solved by the discovery that the highly-ionised oxygen and nitrogen were responsible for its radiation. Also in recent years the mysterious light of the aurora has been assigned to ionised ozygen. The present analysis identified three of the strongest coronal lines with the neutral ozygen atoms in the high solar atmosphere, these atoms being in a very peculiar state of excitation. It is probable that after this important start other coronal lines will soon be interpreted.

" WRITING " ON THE SKY Sky-writing at 20,000 ft. with " frozen " smoke is the latest advertising scheme in England. High-speed aeroplanes, capable of climbing to this height, can write at about twice the speed as at lower levels, and also crosscurrents are lacking, which caused the message to be smeared before it could be completed at lower altitudes. The pilots four miles up wear electricallyheated suits, but the low temperatures improve their writing, since the smoke is half-frozen. At night the advertising is continued by means of searchlights on tall buildings, which projtct coloured patterns against the clouds above.