Stars and Sun

Dr. Charles Greeley Abbot, of the Smithsonian Institution who last Spring made scientific history with his measurements of the sun's heat (TIME, May 5), has now, from the Mt. Wilson observatory, analyzed the heat of nine other great stars--Rigel, Vega, Sirius, Procyon, Capella, Aldebaran, Betelgeuse, Alpha Herculis, Beta Pegasi. He employs the Nichols radiometer, a delicate instrument worked by heat, like the little vanes revolved by sunlight in optician's windows. The stars' light is broken up by the spectroscope into their respective spectra or color bands, the heat in the different parts of which can be measured. These stars represent all the main types, from blue to red.

It was expected that the heat from stars of the same color type would be greatest in the same parts of their spectra, but surprising differences were found. Vega and Sirius are both blue-white stars, but the maximum heat of Vega is much farther toward the violet than that of Sirius. Rigel (blue) shows two maxima, one of which is in the infrared rays, invisible to the human eye. The apparatus detects differences of a hundred-millionth of a degree of heat. That is not enough, say the astronomers. It must be sharpened to a thousand-millionth, and many fainter stars of every type must be examined. Most of these big stars are found to be at least twice as hot as the sun. The present findings are so far significant, at least, that they increase our knowledge of the physical nature of the stars.

The sun strike has been arbitrated, Dr. Abbot now reports. The four per cent, diminution noted since last year has returned to normalcy, and more sun spots are now appearing. A new cycle of spots is beginning in the solar latitudes farthest from the sun's equator, according to observations by Professor G. H. Peters, of the U. S. Naval Observatory. The number and size of spots will gradually increase for about eleven years, until a maximum is reached, when they will again fall off. Electrical disturbances are commonly associated with sun spot increase.

Dr. Abbot and all the Government meteorologists have foresworn longrange weather predictions. The maximum they can risk their reputations on is 48 hours. They will not commit themselves as to the coming season, but many an amateur weather prophet is predicting a long, hard Winter.