WHAT IS GOING ON INSIDE OLD SOL?

Manawatu Times, Volume 61, Issue 273, 18 November 1936, Page 16

WHAT IS GOING ON INSIDE OLD SOL?

ITERALLY “tearing the cover ofl the ball” in an attempt to see what’s inside, Sir Arthur Stanley Eddington, famed British astronomer, introduced some 2500 distinguished guests of Harvard Tercentenary exercises to the world within the sun, a super-heated realm of 10,000,000 degrees centigrade. Here atoms, electrons and x-rays frolic at hide and seek and travel with the speed of light.

Sir Arthur’s talk was one of those rare semi-technical addresses given by a man who ranks with Dr. Albert Einslfcm and Dr. Max Planck as a leader in cosmological theories. He attempted what no other natural scientist would dare to do—to give a detailed account of the merry-go-round of fragmentary atoms as they are thought to be frantically being built up and torn down in the interior of the sun.

‘ How,” ho declared, “we can see moro or less what is happening at 10,000,000 degrees centigrade (18,-000,000 degrees Fahrenheit) in the solar interior. Crowded together within a euLic centimeter there are more than a quadrillion atoms, twice as many free electrons and 20,000 trillion x-rays.

“The x-rays arc travelling with tne speed of light, and the electrons at 10.C00 miles a second. Most of the atoms are hydrogen atoms or, rather, since they have lost their astellite electrons, simply protons travelling at 300 miles ’ a 's'econd. Here and there there will be heavier atoms, such as iron, lumbering along at 40 miles a second. • “I have told you the speeds and the state of congestion of the road, and 1 will leave you to imagine the colli-

THE SUN TORN APART

Astronomer’s Address

v.ons. Small wonder if the atoms aro found with their garb of electrons badly lorn, or even stripped nakod.” The stripped atoms aro pictured as continually capturing free electrons, and so to speak, repairing their dress; but scarcely has the captured electron settled wdien an x-ray bears down on it and explodes it away. “This is not a fanciful picture,” explains Sir Arthur, “these are phenomena which have been found happening in the laboratory when wo use xrays of-the same wave-length and electrons of the same speed as in the sun. There is no need to go b,eyond the limits of terrestrial experiment to discover what is happening to the population, and all tho calculations have an experimental basis.”

The electrons are rushing violently hither and thither, but on the whole they do not get any farther forward, for gravitation pulls them back and keeps tho material of the star in equilibrium. The x-rays, however, gradually lead outwards. They are subject to gravilation, according to Sir Arthur, but because of their velocity of 180,000 miles a second, they have sufficient speed to escape from any star.

“It is just the same- as in the theory of planetary atmospheres, where gravitation is sufficient to retain the heavier constituents, but the lightest atoms have sufficient velocity to escape. The planet thus loses the lightest gases; and in the same way, tho star loses (or radiates) photons of radiation.

“I should explain that, although these photons are X-rays in the interior of the star, they are transformed down to longer wave-length in passing through the last few thousand kilometres of comparatively cool matter, so that it is in the form of light and heat waves that they finally escape.

“So you may picture a photon radiation, barging first one way then another, like a man in a rioting mob—absorbed like an atom and flung out again in a new direction. In this way a photon in the sun will wander aimlessly round in the interior for a million years or more until, just by accident,' it finds itself at the exit of the maze —shoots through—and makes a bee-line across space to the Oakridge reflector where Professor Shapley photographs it. “Having first ascertained the particulars about the population that I have

, been describing, we can apply the laws (based, on laboratory experiment) which determine the amount of obstruction offered by atoms and electrons to the passage of X-rays, and so find how' many photons leak out into space per second. We can compare this result with observation —that is to say, we can see whether Professor Shapley catches as marry of them with liis telescope as (according to our calculation) he ought to catch—in short, whether the star is actually as bright as our calculation makes it.

‘‘ln the last lew years we have found a complication in the calculation which 1 must now explain. At an earlier stage we had to ask the physicist to supply a formula giving the temperature of a gas when the pressure and density are known. Not unreasonably he will object—“you have trot given me enough information. What is the gasp oxygen? iron vapour? mercury vapour? or what? We cannot say—.”

The Eddington lecture was the climax of a day in -which eight specialists in nrany fields of knowledge spoke on factors determining “Human Behaviour. “ liis only explanation of the source of the tremendous energy being radiated by the sun and stars was that the fuel sources are to be fouud within the atoms liberated, by the tremendous temperature? and tremendous pressures. According to Sir James Jeans, a fellow natural scientist and countryman of Sir Arthur, there is sufficient energy locked up within a chunk of coal the sizo of a bowl of peas to run all the steamships on the Atlantic for sixmonths.