What Makes the Sun Hot

Last year Cornell University's brilliant, Alsatian-born atomic theorist, Professor Hans Albrecht Bethe, trotted out a plausible explanation of how the sun converts hydrogen into radiant energy, and so keeps on shining (TIME, Feb. 27, 1939). At temperatures above 15,000,000DEG C. (the sun's internal temperature is calculated at 20,000,000DEG C.), Dr. Bethe found that hydrogen atoms would attack carbon. The carbon would be transmitted into other forms, but after a series of six separate atomic conversions, it would reappear, while hydrogen atoms (of which the sun has enough to last some 12,000,000,000 years) would be consumed, leaving helium as ash. One cycle would take about 52,000,000 years, but there would be enough cycles going on all the time to keep the sun hot. Though Dr. Bethe carefully observed mathematical flying rules, he calculated all this in the blue sky of pure theory.

Last week, at a meeting of the American Physical Society in Washington, Dr. Bethe told how he and others had brought his sun theory down to earth, in laboratory experiments which actually accomplished the atomic interactions he figured out. Though nothing remotely near the sun's internal temperature can be produced on earth, electric energy can be substituted for heat energy to bring atomic particles up to high speed. Three of the six steps in the solar cycle were duplicated by Bethe and a co-worker at Cornell. A fourth was managed by two physicists at England's Cambridge. Then the Bethe team at Cornell performed the fifth and sixth steps. The experiments indicated that the theory should be corrected at one point--a complete solar cycle, instead of covering 52,000,000 years, should require only about 6,500,000 years.

This file is automatically generated by a robot program, so reader's discretion is required.