Nelson Evening Mail. SATURDAY, JULY 24, 1909. THE SUN & THE SUN SPOTS. IS THE EARTH AFFECTED?

Nelson Evening Mail, Volume XLIII, Issue XLIII, 24 July 1909, Page 2

Nelson Evening Mail. SATURDAY, JULY 24, 1909. THE SUN & THE SUN SPOTS. IS THE EARTH AFFECTED?

ACCORDING to Mr Clement Wragge, there is a. huge storm, estimated to be about 30,000 miles in diameter, raging in the sun. He further goes on to state, as reported in last Thursday's "Mail," that seismic, magnetic, and other disturbances may be expected 'n various parts of the world. Mr vVragge is saying a good deal, and his prediction is hardly ia accordance with the vie-ys held by many scientific men both in England and on the Continent. It Is not necessary to dwell upon the importance of the sun to the earth, which without his light and warmth would be a 'black uninhabitable void, but itss interesting in the face of Mr Wragge's' remarks, and also because of the attention that is -sow being devoted to. the sun by eminent setentists, to review as fully as can bo done in the course of a 6hort article, man's knowledge of this great star, and to touch briefly upon oom? of the latest conclusions that have been based .ipon the known facts. To those who have not devoted any at--.e»t<on.to astronomy it seems incredible tlut mirti can actually measure the size of the sun * but this has been done ,and it has been found that the diameter of the sun is 865,000 miles. Y-efr this bare statement of tho dimensions of the great globe fails to awaken an adequate idea of its vastness. Astronomers give this example: If a rialway were laid round the sun, and an express train moving 60 -nilse ar. hour were started, it wonld have to travel night and day for five yeers without intermission bofore the journ.-'y waß accomplished. When compared with the earth, thfl stupendous size of the (tun becomes more apparent. If his gio-be .were cpt up into one miiibn parts each of thtse parts would appreciably exceed the bulk of the earth. Everybody knows that the actual dietnnsa of the sun from "the earth is about 92,700,000 miles. This number Ls beyond comprehension. It is said that if it were to be counted it would be necessary to count as quickly as possible fo.- threo days' and three i nights before one million was completed ; I yet this would have to be repeated near* I ly 93 times before <ijl the miles between I the earth and the sua h»d ljt.en counted. ( • »<•»»» i It is well known that many 1 of the "myriad host of stars* i which stud the sky at night 1 aro each one a mighty sun, actually ri* t vailing, and in .many cases surpassing, t the splendour of the earth's luminary. \ But it is not as a star that the sun a has to bo dealt with. To the earth his t proximity gives him an importance in- e calculably transcending that of all the r other stars. To. the unaided eye the euri t appears to be aflat circle. Now the firßt t questions that need to be dealt with are 1; — is the globe a solid mass, or is it t: liquid or gaseous? Through ihe -tele- y scope it is seen that the surface of the r sun is not generally uninterrupted. There E are here and there oa the surface small b

dark spots called sun-spots. These spots vary both as to thoir size and as to ( number. When photographed tliese re- ; semble small black holes with a. dark central part, and a lighter margin. Various theories have h^en propounded/! as to the nature of these curious Matures, and one of the early suppositions was that thev were merely objects situ- < ated between the earth and the sun ana ( thus projected on the sun as a background. This has been proved to be . false, for wheh the sun is watched tor a - few days it is seen that these spots vary in size and seem to mova towards the edge of the surface. This is a most . important . fact, for besides indicating : that these spots really exist upon the sun itself, it proves conclusively that tho sun revolves round on its axis similarly as does tbe earth. By carefully watching th-ase spots for a succession ot days, ard for prolonged periods, astronomers have discovered the exact time it takes a spot to travel across the surface of the sun. On the 2nd March 1627, the skilful astronomer Scheiner observed a spot on the edgo of the sun. •He watched it carefully for a number of days, and on the 14th it approached the other side. It has. also been noticed that when the spots disappear at the edge of the sun, they remain invisible for twelve or rhirtecn days, md then o.ften re-appear at the other edge. It is therefore obvious that tbe spots must- move round th9 back of the . win in about the same time that they occupy in crossing his face. Further inquiries on this subject have enabled the movements of the spots to be measured with accuracy, and it has been phown that each spot accomplishes a complete revolution around the sun in about twenty-five days and five hours. Sometimes a little longer is taken. But by no means are these the only mo /ements of th-.se spots. They are always appearing and difeppearin". Thus, it has been concluded, there is evidence that the sun for the most part is not a solid mass — is not even a liquid mass — but that the sun, as far as astronomers can tell, consists mainly of matter in the gaseous or vaporous condition. There is another feature, and it points to an intimate connection between the phenomena of sun spots and the purely terrestrial phenomena of magnetism. It has boen noticed that the occurrence of the maximum of sun-spots occurs simultaneously with an unusual amount of disturbance of the magnetic needls. Another mysterious law governs the sun spots. Their number fluctuates from year to year, but it ssoms that the epochs of maximum sun spots succeed each other with a certain degre© ot regularity. Observations of sun spots for nearly three centuries show that tho recurrence of a maximum takes plaM, ou an averago, every eleven years. Another Important feature of the sun is the corona, which are the great masses of flamo that fringe the sun. It will be remembered that these were specially., dealt with a few Saturday's ago when the expected eclipse of the sun next year was being dealt with in these columns. Tho great streamers are invisible to the naked eye, except when a total eclipse occurs, and the moon completely covers up the sun. Sir Robert Ball, referring to the corona in one of his valued works, remarks that all indications point to the surface of the sun as tn'eseit q{ fhe most frightful storms and tempests, in' whuilj the winds sweep the incandescent vapours" furiously along. The valopjty at }yl)i.ch, some of these flames have been known tp sKp.ojfup E^s Leen calculated at 200,009 mji.es an 'hour, which when worked out has been, founc! to be more than 100 times as grait fi§ that of the swiftest bullet that was ever fired from a rifle. It is interesting to ncte that the earth intercepts only the merest i. action of the light and heat of the sun. Asronomers put it down as less than' the one 2,000,000,000th ■p.srj, of the whole. Recent observations liave " proved that the storms aro very powerful magnejic; disturbances. Whether the magnetic dislai-.b.-j-iec is the cau=6 of the sun-spots or is m£r,ejj- -issneiated with them, is at present uuk-jo-wii, bs.t • here is no doubt whatever that tliero if; n powerful magnetic disturbance connected with the sun spots. Ei-jhtcon months ago it w^s found that the magnetic disturbances on ill" earth did not occur whenever there were a numbey of sun-spots, but only .when the spots h»<J a particular relative position with regard to tlio earth. It would appear therefore that tie influence of the sun-fc|>ots is not widely dispersed, but is contracted jind given out in csrlain definite directions. Joyless tho earth happens to be in that particular direction it does not feal any influence from the sun-spots. Up to the present — but important developments are rapidly occurring— it js the belief thai, the disturbances merely cause magnetic disturb? ances on the earth, and are not responr sible for any seismic action. Space does not permit reference to tho amazing results that have been achieved by means of the spectroscope, and thix must form th6 subject of a future article. The "scienee" of predicting earthquakes is a pretty sure occupation, considering that 400 occur every year.