Star Heat

There being no more comets or eclipses scheduled for this summer, Dr. Charles G. Abbot, assistant secretary of the Smithsonian Institution, left Washington last week for Mount Wilson, Calif, (near Los Angeles), to pursue what has been his special study for many years, the heat of stars. Dr. Abbot has climbed the world's most arid mountains to study the sun's heat. Subordinates of his are at present sitting in an extinct South African crater continuing this work, an immediate purpose of which is to facilitate long-range weather prediction. But far more difficult to measure than the sun's heat, and of more abstruse scientific value, is the heat of stars many light years/- away.

From star heat may be calculated star ages, star diameters, star compositions. Star heat is undiminished by billions of miles of passage through universal vacancy, but when the radiations enter Earth's heavy atmosphere they are dispersed, feebled and as difficult to detect and measure as a whisper in a hurricane. Star heat is best studied at altitudes where Earth's atmosphere is rare. To rare-aired Mount Wilson, therefore, went Dr. Abbot, where he can introduce starlight reflected from the 100-inch Carnegie Institute sky-reflector into his newest and finest radiometer--an instrument so delicate that a part of it is constructed of flies' wings; an instrument ten times as sensitive as Dr. Abbot's last radiometer, with which, "if the Earth were flat and the atmosphere perfectly transparent, it would have been possible to have measured in California the heat of a match struck on the Mississippi River."

/-One light year equals approximately 5,765,696,000,000 miles--the distance light can travel through air in one year.