SUNSHINE TO COME.

Ashburton Guardian, Volume XLVII, Issue 10806, 29 December 1926, Page 6

SUNSHINE TO COME.

RADIATION AND TEMPERATURE.

The interior <w the sun must nave <a temperature of -70,000,000 degrees Fahr. at tlie centre, which gradually decreases until it is only about 10,000 degrees at the surface.- That this is necessary to keep the sun at the size it is at present, and to prevent the gravitating mass of the outer part from collapsing to the centre, is the opinion of Professor A. S. Eddington, professor of astronomy at Cambridge University, stated iu a series of lectures at King's College, of the University of London. Professor Eddington is quoted by "Science Service's Daily Science News Bulletin" (Washington) as saying that as a result of this conclusion "no source of energy is of any avail unless it leberates heat in the deep interior of a star." This, he 1 believes, effectively disposes of the idea that the sun receives its energy from meteors falling into it from outer space. "Clearly," lie states, "you cannot maintain a tem-perature-gradient by supplying heat at the bottom end. If this year the sun encountered a swarm of meteors, which bombarded it with enough energy to furnish a year's supply of radiation, that would not add a year, or even a day, to the life of the.sun; its internal readjustments would go oni unaffected. All that would happen would be that the sun would give us twice the normal amount of radiation this year." We read: "The theory once proposed that the sun is gradually contracting, and so releases the energy which forms the heat, is also untenable, because with such a theory the sun cannot be more than 46,000,000 years old. Physical and geological evidence seems to be conclusive that the age of the earth—reckoned from a period which by no means goes back to its beginnings as a planet—is muchr greater. The age of the older rocks found from their uran-ium-lead ratio is generally put at 1,200,000,000 years." . Astronomical facts also support these ideas of the age, of the solar system, and so we seem to require a time-scale which, will allow at least 10,000,000,000 years for the age of the sun; certainly w© cannot abate our demands below. 1,000,000,000 years. Since we cannot very well imagine 'an extraneous l source of heat able to release itself at the centre of the star, the idea of a star picking up its energy as it goes along seems to be definitely ruled out. It follows that the star contains hidden within it the energy which has to last the rest of its life. But energy cannot be successfully hidden: it betrays itself because it has (or because it is) mass. How | much of the 'Sum total of the energy I of the sun is capable of being converted into radiation we do not know, but if it is all available, there is enough to maintain the sun's radiation Tab the present rate for 15,000,000,000,000 years. To put the argument in an- | other form, the heat emitted by the [ sun each year has a mass of 120,000,-1 000,000,000 tons; and if this loss of mass continued there would be no mass I left at the end of 15,000,000,000,000 years.' Since all the- other possibilities ' are eliminated, Professor Eddington supposes that the source of energy must be in the protons and electrons, • charges of positive and negative electricity, of which the atoms are composed. We have' to suppost that a proton and electron/ run together, their electric charges cancel, and nothing is left but a splash in the ether, which spreads out as an electro-magnetio wave carrying off x the energy. He admits the difficulty of some of these ideas, for apparently at a temperature of 70,000,000 degrees the energy is liberated so copiously that he asks, "can we suppose that energy issues freely from matter at 70,000,000 degrees as steam issues from water at 212 de-!| grees. I think that physicists would j be hard put to it to reconcile such ex- I traordinary behaviour with any ac-1 cepted principles, yet that is what the j astronnomieal observations taken at its j face value seem to insist." |