Stars
HEAT OF. The heat of nine great stars-namely, Rigel, Vega, Sirius, Procyon, Capella, Aldebaran, Betelguese, Alpha Herculis, Beta Pegasi-was analyzed from the Mount Wilson Observatory, by Dr. Charles G. Abbot of the Smithsonian Institution. He is the same scientist who previously had succeeded in measuring the heat of the sun. In making his measurements he uses the Nichols radiometer, a delicate instrument worked by heat. The light from the stars is broken up by the spectroscope into their respective spectra and the heat in the different parts of these can then be measured. The stars measured will present all of the principal types, from blue to red. Some of the expectations-such as, for instance, that the heat from stars of the same color type would be greatest in the same parts of the spectra-were not realized and surprising differences were found. Although the apparatus used detects differences of a hundred millionth of a degree of heat, astronomers claim that this is not sufficient but that it must be sharpened to a thousand millionth, and to a must be examined. Most of the big stars that many fainter stars of all types measured were found to be at least twice as hot as the sun. The principal sig. nificance of these new measurements is that they have increased greatly our knowledge of the physical nature of stars.