THE NEAREST STAR.

Star (Christchurch), Issue 7233, 21 October 1901, Page 2

THE NEAREST STAR.

SOME INTERESTING ASTRONOMICAL INFORMATION. Under the heading of " Glories of Southern Skies," the '"Leisure Hour " has an in- : t'eresting article on the stars of the south. It refers to the brighter of the two stars of the familiar "pointers," Alpha Centauri: — In the skies of the Southern Hemisphere there are numerous constellations, clusters of -stars, nebula?, and, other celestial objects that aie never seen in Europe, as they are always below the horizon- in latitudes far north of the Equator. Many of\ these objects are of surpassing splendour, and the brighter skies of southern regions enable them to be seen witi much greater distinctness, and with far greater frequency, than similar objects are seen in the mistladen atmorphere cf Great Britain. So far as is at present known, the nearest fixed star in the whole heavens is Alpha Centauri, a brilliant double star in the constellation of Centaurus, not far from the well-known Southern Cross. The most magnificent cluster of stars in the visible universe is that known as Omega Csntauri, also in the constellation cf Centaurus. The large and small Magellan Clcuds are wholly dissimilar frcm anything visible in Europe; whilst the nebula round Eta Argus, in the constellation r-.f Argo, the glorious Southern Cross, and the splesdid portions of the Milky Way that include and surround these constellations, render the whole region very striking and deeply interesting. Let us first deal with, the star Alpha Centauri, situated frcm our system by the enormous distance- of twenty-five billions of I miles. Suppose we adopt a scale for the model of a, million miles to the inch. Take : a marble rather under an inch in diameter !to represent the sun. A grain of coarss sand cr a pin's head placed about 7it Bin from the marble would represent the earth:; then. Alpha Centauri, on the earn? scale-, 1 would bs represented by aftc-tber such taarble placed at a tlistarca of 59*5- miles. If the marble representing the sun in the model is placed in London, the marble representing the star would have to be placed in Aberdeen ! If this is the scale for the nearest star, what are we to say of the most distant ones that leave their images on sensitive photographic plates in star cameras after many hours of exposure? .Seme of these stars are considered to be many thousands of time* more distant. T:ie magnificent cluster of stars known as OnK^a Centauri is faintly seen in *c.uth-ern-skies with the naked eye. When viewed through a powerful telescope, it is found to consist of about 6400 stars, of !ibcut the fo.urth magnitude,- forming almost a blaze of light in the centre. It is beyond all doubt the richest and the largest object of its kind in the heavens. Some idea of the vast distance- that separates this cluster of suns from us may be formed' from the fuct that the united light cf the 6400 stars shines in the sky with i:o greater light than a single star of 'the font h magnitude would do. Large m;:ii'i>e-rs of i'nscomponent stars in this cluster arc variable, upwards cf one hundred of these vaiying in brightness in short period 1 ?' of under twenty-four 'hours. This globuhu* cluster of suns is a universe in itself, and the conclusion seems to bs that worldis revolving round these suns would have perpetual tlayligM. The blaa& of light to the inhabitants of these worlds would hide all external systems, so that here we have the strange anomaly that an excess of light may hide more than it reveals. Id is difficult to imagine the complicated' conditions of light and heat which would obtain -on worlds circling round individual tuns of the associated group of suns forming these globular clusters, and the climatic conditions that would result from 'the occasional close proximity oi other pubs of the group. The Magellanic Clouds are remarkable objects in the southern sky. forming two bright *.pots, roughly circular, of milky light, looking liks patches of the Milky Way, but. are not in any way connected with the Galaxy. The larger cloud, or Nubecula Major, occupies, a &paie in the heavens about two hundrsd times ths apparent size of the- full moon. A good telesccpe shows that ir consists of about two hundred clusters and nebula, besides many thousands of erais. Mr jßusssll, the* Government Astronomer ar Sydney, says: — '"The whole of this great cloud is a complex spiral nebula., with two centres, if fl may *v express k." This q-.iral character was fii>t noticed by him on some photographs taken in 1890, and tlie discovery is a vci-y reiiitukable one. and 1 corroborates Sir John Hsischel's ejattms-nt made long ago. "that the Nubecula? aii to b? rtjjaiied ;is systems ;iii gti.tiis. and which have no analogues i:i ihe .Yo-duui Hemisphere. The btit known spiral ntbula iv the heavens is the wry rem-arkable one in ih-e cor.stellatidii of Canu* Ve-n<itici. or Tiie Greyhound?:, and iheae are oiher spiral xwbula> in i..iier parts of the s!:y. In this instance, however. -,v«j have the whole- of the gi-sat ■Magellan Cloud, with its swarms of uabulse and clusters, formin* a gigantic spiral of ittsli. #