In a recent interview with the CRIMSON, Dr. Theodore E. Sterne, Princeton '28, research associate of the Harvard Observatory, reviewed the most important theories now held by astronomers in regard to the source of the sun's energy, and explained his own theory which has recently been accepted as the most promising. The number of calories the sun loses per second may be represented by the figure 1 followed by 26 ciphers. It has long been a moot question as to where this energy comes from, and a study of possible sources has brought forth several theories.

Perhaps the first important theory was the belief that the sun was a burning body such as a piece of coal. However, a mass of chemicals as large as the sun could not react for longer than 10,000 years.

Hale, an American astronomer, believed that the sun was contracting. Contraction is knows to be a source of energy.

Sir James Jeans, an Englishmar, supported the obviously non-disputable be-let that the interior of the sun was composed of highly radio-active elements that are not known to exist on the earth.

Einstein's law states that if a gram of matter could be turned into energy it would yield 2 (followed by 13 ciphers) calories. Sir Arthur Eddington has used this fact to show that the energy of the sun may be derived from the annihilation of matter. Although this theory has not been entirely disapproved, it is doubtful whether matter can be destroyed so easily.

Dr. Sterne has advanced a step further and has shown that if the sun's temperature were 1000 million degrees or more, all matter existing on it would be, not explosive, but quite passive. In this case transmutations of the elements would be in equilibrium rather than tending to go to completion. Dr. Sterne believes that according for 1 (followed by 11 ciphers) years. This would involve compression or cooling or both, and may be compared to what goes on in a gasoline engine when the temperature is sufficiently high to permit equilibrium taking place.

The Sterne theory has recently been partly confirmed by showing that temperatures of twenty or thirty million degress are low enough to cause the stars to be explosive.