The Sun's Heat.
How it is Maintained—How Lokg it is Likeit to Last. r How is the heat of the sun maintained? How long has it lasted? How long will > it continue P Two theories are adranced. The first that the heat is caused by THE PLANETS FAILING INTO THE BVX. From its present orbit, by which it appears that Jupiter would maintain the son's present expenditure of energy for 32,254 year 9, and Mercury for six years and 219 days, and that the collapse of all the planets upon the sun would generate sufficient heat te maintain its supply for nearly 46,000 years; and after estimating that matter equal to only about one onehundredth part of the mass of the earth, falling annually upon the solar surface, would maintain its radiation indefinitely, Professor Young thinks it improbable, from astronomical reasons, that any such quantity of matter can be supposed to reach the sun. So large a quantity of matter would necessitate a vastly greater quantity circulating around the sun, between it and the planet Mercury. But if there were near the sun meteoric matter equalling,, for example, the mass of the earth, it ought to produce an observable., effect on the motions of Mercury; and no such effect has yet been made. Astronomers, therefore, failing to find a full explanation of the cause of solar energy in this hypothesis, hare adopted a second one, which is that THE SUN'S DIAMETER IS SIOWIiT COX* TEACTING, And that the gaseous mass is gradually liquefying and becoming solid. The conclusion is drawn that if this theory be correct there must come a time when there will be no solar heat, as there has also been a time when it began. How far forward is the end, how far backward the beginning ? Newcomb is authority for the statement that with its present radiation the sun will shrink to half its present diameter in about 5,000,000 years. Beduced to this size, and eight times as dense as now, it will cease to be mainly gaseous, and its temperature would begin to fall. Henoe Newcomb assigns as the term during which the sun can supply heat enough to support life on the earth, as we know life, a period of ]0,000,000 years. The writer somewhat more confidently casts bis eye backward, and concludes that the sun cannot hare been emitting heat at the present rate for more than 18,000,000 years, if its heat had been generated in the manner described. The possibility of collision with wandering stars, and the suggestion of ways as yet unconceiTed of for restoring wasted energy, are followed by the statement that " the present order of things appears to be limited in either direction by terminal catastrophes which are vailed in clouds as yet impenetrable."
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Thames Star, Volume XII, Issue 3834, 12 April 1881, Page 1
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464The Sun's Heat. Thames Star, Volume XII, Issue 3834, 12 April 1881, Page 1
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