RADIUM AND THE SUN.

New Zealand Times, Volume XXVII, Issue 5731, 28 October 1905, Page 10

RADIUM AND THE SUN.

In tho early days of electric lighting an exhibition was held at the Crystal Palace, where admiring crowds flocked to view the varied manifestations of the nevr wonder. The building had become

r. veritable fairy palace, ablaze with a pure soft light, displayed in every form from, tins tiny glow-lamps, needing among fountains and turning thrur spray into silver, to the powerful arclamps which transformed tho blackness of night into the broad white light of day. But much more. Hero and there tho currents were diverted into other channels, and made to perform a multitude of different offices. . Machinery of all kinds was put in motion. Heating, cooking, photography, and a hundred arts were carried on by tho agency of ono and the same subtle power. And when all this varied display had been examined, tho visitor was conducted to tho basement, whore the solemn furnaces wore aglow, and tho a.ir quivered with sullen heat. And then the thought came homo how the little world of varied wonder and beauty overhead was simply the outcome and adaptation cf that common form of energy which gleamed through tho furnace doom. Hightly considered ono could see hero in miniature a presentment of what is taking place in the great world without. The wholo machinery of life, and all that pertains to lifo on our planet, is but the outcome of ono grand source of energy. Wo gather the fruits of the earth to sustain our being, Wo behold and revel in tho light of heaven, wo bask in tho gonial warmth of summer, and gather round tho blazing logs on winter nights. We feast our eyes on tho beauties of Nature—tho verdant fields and forests, the waterfalls, tho cloud-forms in tho blue vault above. By tho magic power cf steam wo speed across the breadth of continents and traverse tho wide ocean by tho aid of tho winds of heaven. And then when we pause to consider wo trace tho source of all simply to that great fumaco fire, tho sun, which hourly manifests his might in those and a thousand other ways. Hero too science has shown us how wo may look through a chink in that mighty furnacc-door, and catch a glimpse of what is taking place within. Let us follow a little way. along the path of discovery, and in imagination approach our great luminary. His mean distance from us we know accurately enough to bo about ninety-two million miles; but what is a. million? How can wo get an idea of it? If a courtyard twenty-eight yards square were paved with halfpence, about a million halfpence would bo lying there. Listen to a clock ticking seconds. You would havo to listen on day and night for cloven days and a half before it would liavo ticked out a million.

But perhaps wo may bo able to think of a bettor example. In walking a milo you 1 take about two thousand paces, and so in n five-mile walk, i. 0., in an hour or so. if you wont on counting your footfalls, they would have reached ton thousand. Continue this a hundred times over, i.e., walk all the way from Hlydo Park’ Corner to the market-place at Inverness, and you will have made a million paces. But once again, imagine that at each pace, instead of going a short yard you were enabled to make a giant stride of a whole mile; then by tho time that a.s an ordinary man you have reached Inverness you would as a giant have nearly reached tho moon. Yet oven so, try and conceive it, you would have mado but a ono day’s march out of a year’s journey towards reaching the sun.

Lord Grimthorpe, neglecting the sun’s pull on tho earth, mado the following interesting calculation—“lf tho carta were a cannon hall shot at the sun from its present distance with tho velocity it now travels with, and tho moment of explosion telegraphed to the sun, they would get tho telegram in about five minutes and eeo the earth coming in eight minutes, and would have nearly two months to prepare for the blow which they would receive about fifteen years before they heard the original explosion.”

But if his vast distance is hard to conceive, his monster size is perhaps yet more difficult to realise. In diameter more than a hundred time that of our earth, in bulk more ban a million times. Wo sometimes ego a huge ring or halo round tho moon occupying a space in tho heavens so largo that ninety moons’ breadths would but just suffice to span it. Yet tho body of tho sun would fill ell that spaco cro wo had approached within two million of him. Onco on his apparent surface, were wo permitted to travel thereon and with the speed of an express train, it would require five whole years of continuous journeying before wo could make tho circuit of his orb. Or, to take another calculation, were our own earth to begin expanding, its shell would have to widen out on all sides until ifc had reached the moon, and as far again into space beyond, before its dimensions equalled those of the sun. But it is when w© come to try and form a conception of his might thatonr imagination is taxed to tho utmost. The mere sheer pull of his gigantic mass is so tremendous that could a man bo placed upon the sun ho would bo instantly crushed by his own weight as by a burden of tons. A consideration of the heat he emits is equally overwhelming. If we could imagine nearly a ton of coal an hour burning on every square foot of the sums surface eternally. then wo should have a conception of the sun’s radiant heat. Or look at tho same thin" as Professor Young ha.s put it. “If/tho sun were tO'Comc as near us as tho moon, tho solid earth would melt like wax.”

Many speculations have been advanced to account for tho of the sun’s heat, but an earlier question seems to arise. Is that heat being fully maintained, or is it declining, and is the sun speeding on towards that ultimate stage already readied, as wo have reason to suppose, by many other stars whoso fires havo died down and their light gone out for ever? Thai is in every way probable, yet there is no direct proof of such a fact; history can point to no indication of the kind. Winter frosts do not- seem to have been less severe in ancient history than today. Two thousand odd years ago the Carthaginian generals found tho Alpine snows as impassable as now. Only a few degrees southward of the British Isles the vines grow luxuriantly, and but a little further south, the sugar canes. Hero and there, as in sheltered nooks of Cornwall or the tho aloe and tho palm will flourish on British soil; but wo havo no evidence in all history that these forms of vegetation could establish themselves cleewhero in our islands. Even though we go back to geological ages we havo no certain revelations, save that the earth was once hotter #*ith internal fires, and that alterations of tropical .and Arctic ages camo and went in obedience to alterations in our path around the sun.

On tho other hand, wore the sun merely a body cooling down, in space without fresh accession of heat, we must hare long since found evidence of

this, and it has been stated that were tho sun composed of any conceivable fuel in combustion, then that sun which, say, looked down on the Pharaohs would ore now havo nearly died down to darkness. Various theories have been proposed to account for the constant renewal of tho sun’s heat, cue cf which, in spite of recent discoveries, demands our close attention. It lias been suggested that tho impact or fall of matter on the sun might re.Aoie its heat, and this becomes plausible when calculation shows that in the neighbourhood of. the sun. a body falling through a single inch would acquire a velocity cf hundreds of miles pior hour. Then, again, the conception of an indraught of matter on the sun gains on tho imagination when, as sometimes happens, we catch .a. glimpse of that striking phenomenon in the sky known an tho Zodiacal Light, a nebulous, cone of liglit somewhat resembling tho Milky Way, which, starting from that point of tho heavens where the civil has just set, or where it is just about to rise, tapers upwards in tho sky, forming in reality a vast lens-shaped mass, lying in the piano of tho planets, extending from close in upon the sun to perhaps as far as our own orbit, and commonMp supposed to consist of meteoric matter. Again, meteorites are constantly falling on our earth, a fact V'hich might stem to lend further corroboration to this theory, oul ythat it, is really here where tho objection t oft begins. to como in. For mathematical reasoning shows that if tho sun is merely refreshed by falling matter, then wo on earth ought to be molested to such an extent that it would not bo safe for u.s to go abroad without somo form of meteoric umbrella. Moreover, Venus, and yet rncu-o Mercury, being still more in the storm, ought to give somo evidence of actual pertubation therefrom. Speculation on somo such lines as those was all that astronomers had to bo content will only a shor while ago, and wo can now look at what they had been able o learn from actual observation. Among tho earliest objects to arrest their attention wore tho spots which at regular periods of about eleven years appear on tho sun’s surface, ehief,ly on two zones, fairly corresponding in position with tho belts on the earth where the trade winds blow. When definition is particularly good the entire surface wears’ a mottled or corrupated appearance, as of bright cluods separated by minute interstices or pores. These clouds havo been fancifully compared to rice-grains or willow leaves, and give tho idea, of being suspended over a darker atmosphere within; while a spot suggests a vaster rift among these clouds, often vast enough indeed to allow of a body as largo as our earth falling clear through its aperture.

When an aeronaut has ascended in broad day, say a couple of miles above the eart ,hit often happens that the view below will fill in with cloud, in which case its upper surface is of dazzling brightness; and if an opening should present itself allowing empty space below, this appears dark hy contrast, and such an aperture may, by way of illustration,, bo compared to a spot on tho sun’s face or photosphere. The strange shapes and curious changes in the spots are beyond all wonder, and ono chief spot in a group will sometimes rush forward, leaving its smaller companions many thousand miles in the lurch. The evidence of all this, and of tho fact that tho sun’s density as a whole is far less than that of our earth, gees to prove that his outer surface as presented to us is composed of intensely luminous gases which are being swept along by solar tempests of inconceivable fury. A further evidence of those terrific storms is afforded by outbursts resembling tongues of red flame, mainly composed of incandescent liydrogen, .‘-con to bo playing around the limb at the time of a total solar eclipse. These appearances termed .Solar Prominences, are thrown outwards into space to heights of our loftiest mountains; and reaching those supremo altitudes in an interval of time to bo measured by minutes only. But astronomers had seen and noted other of tho sun’s belongings. It is at tho time o fa total solar eclipse, when tho bright surface of the sun is shielded by the dark body of the moon, that tho ethereal inexplicable glory called tho Corona is scon. This wondrous appendage which has puzzled observers of all times remains still in mystery. A story is told of a learned professor who. while examining a class in astronomy, asked one of his pupils the simple question, "What is tho Corona?” Upon which the individual appealed to, being at a loss, fell hack o na reply, the like of wide hwo have all hoard before .—“Ho had known, but was very sorry ho could not recollect just then.” This evoked from hiso senior tho ironical rejoinder, “What an incomparable lose to Science! To think that only ono'man in all the world has known what the Corona is, and that lie has forgotten it 1”

Its wonder is in keeping with its rarity. Were a man already grown old to have devoted the whole of his life to witnessing every available solar eclipse, all the fleeting opportunities of observing the Corona added together would probably not reach half an ho'ur. It has been supposed that the Corona may havo an electric origin, and alters its form and appearance through a cycle of years corresponding with that of a sun-spot period; and it is at least certain that the outbreak of sun-spots is closely connected with magnetic disturbances. Extending outside tho Corona arc systems of long rays which stretch away far into space, and those rays, in accordance with recent researches made by Mr E. W. Maunder, are now conceived to be visible manifestations of magnetic influence which emanate from areas of disturbance on the sun’s surface, and strike the distant earth “like streams from a fireman’s hose.”

But, as may be supposed, it was by aid of the spectroscope that astronomers bad gathered the most important information as to the nature and condition of tho actual elements which constitute the sun’s being. Applying the instrument to one of these spots it at once reported that those mysterious caverns are regions of comparative coolness, and, moreover, that tho vapours within grow denser as greater depths are explored, and that below all is some white-hot solid or liquid, shining through luminous vapour. There seems to have been little else discovered or discoverable, save that the elements thus far found in the sun were for the most part, but not quite entirely, those known on our own earth.

"With the acquisition of so much positive knowledge it had reasonably been supposed that the constitution of the sun had in the main been analysed. But tho aspect of this perplexing problem lias undergone a radical change within the last two years. The latest discovery of science has altered our conception of many problems, and of this among the number. This last discovery is of Radium, and of other substances radium-like activity an activity which to our senses appears eternal. For radium is considered to go on producing heat practically for ever. One of pur greatest

] astronomers and mathematicians gives j as his opinion rhat “wo have no right I to assume tha tthe sun is incapable of I giving out energy to a degree at least 1 comparable with that width it would j do if made entirely of radium.” j What a thought have we here! If ' the sun wore all radium, or composed of j matter behaving like radium, what then? Is it conceivable that any source of energy is tcmal ? To our almost certain knowledge suns that now arc dead and cold Ho strewn through space; others shine feebly and Hull red like heated iron which is cooling and sea.sing Ho glow. Look on far enough into the unknown future, and will it become literally and lastingly true that the sun shall bo darkened, and tho moon not give her light? What then? To the eye of the universe ono small star will havo censed to shine! Surely wo cannot rest content with this thought. Lot us rather quote tho eloquent and prophetic words of Sir Oliver Lodge: “Tho atoms arc crumbling an ddocayijig. Must they not also bo forming an (looming to tho birth? This last we do not- know as yot. It is tho next thing to bo looked for. Decay only without birth and culraintion cannot bo tho last word. This discovery may not come in our time, but Science is'still rapidly growing, and it may. We now know things which have been hidden from tho wise and prudent of all time. Surely somewhere there must bo i'oy at seeing man thus entering into his heritage, and realising those primal truths concerning his material environment whereof ho has been living in ignorance all those thousands of years.”—“Leisure Hour.”