CAUSES OF AURORAE

New Zealand Herald, Volume LXXV, Issue 23089, 14 July 1938, Page 16

CAUSES OF AURORAE

ABTRONOMICAL LECTURE Causes and olfects of the aurorae which periodically appear in the skies were ({escribed by Dr. D. Brown in a lecture to a meeting of the Auckland Astronomical Society, held at the University College last night. Dr. Brown said it was known that aurorae wore caused by electrical particles shot out from the sun, and that these affected by the earth's magnetic field, because they were the cause of some magnetic storms. The exact nature of the electrons which formed aurorae, and what it was that held them together in transit toward the earch, had not beon discovered, he added. Dr. Brown said thero were two types of aurorae, One occurred during daylight hetween 200 and 000 miles from the earth, and usually extended over several thousand miles, The other, observed after dark, was always under 200 miles from the earth, and was more or less local in character. From recognised records kei>t over a period of 20 years, it was shown that the closest an aurorH occurred in relation to the earth wns 55 miles distant, and that the highest one was 025 miles away. The most common aurorae occurred at a maximum distance of about 06 miles.