THE UNIVERSE.

Hawera Star, Volume XLVIII, 5 July 1924, Page 13

THE UNIVERSE.

SOME IDEA OF ITS EXTENT. ASTRONOMERS REVISE THEIR ESTIMATE. A nebula so small that it is invisible to the naked eye, and so far away that it takes a million light years for its rays to reach the earth, has caused astronomers to revise their estimates of the size of the universe, according to the Abbe Moreux, the French scientist, who is a frequent contributor to the Petit Journal. Writing on the subject the learned Abbe calls attention to the fact that new estimates of the extent of the universe must be based upon the foundation laid down by an American, Horrow Shapley, of Mount Wilson Observatory, who in 1918 discovered that rays from the most distant star cluster of the Milky Way take 200,00'J years to reach the earth. Since then, says Moreux, Shapley lias gone further afield. (

“I do not believe,” he writes, “that there exists'Tn the whole domain of astronomy, vast as it is. a more absorbing s tudy than that of the nebulae, the name which the astronomers have given to those little milky spots or patches with which the sky is scattered.

“Formerly, before the invention of the telescope, the ancients used to include in their records —restricted it is true —all objects which appeared nebulous to the naked eye but since glasses have provided the means whereby the savants have been able to scrutinise the heavens a distinction has had to bo made. To-day confusion is barely possible; clusters of stars and nebulae are of quite a different nature. “For certain, objects, all instruments employed have been useless to determine them. The nebulae proper are but huge masses of gas in process of condensations, and each day by means of photography our investigations seem to multiply them immeasurably. At the. time of William Hersehel, the known nurqber of nebulae was little more - than 2000, whereas the great, telescopes of the nineteenth century could distinguish as many as 120,000. It is not too much to say that it is possible, by means of the famous mirror which is used at Mount ,\Yilson, in America, to bring this number up to a mil lion , either by direct vision or by photographic procedure.

“Such, a prodigality is surely enough to convinde even the doubters that the field of astronomy is practically unlimited, and in spite of the discoveries of which jnankind is proud, there still remains a. vast horizon to be explored, and which is much greater than our timid investigations had caused us to suppose. We' shall leave aside the question, interesting though, it he, of origin, constitution, and evolution of the nebulae. There is too much mystery still, and even our .greatest scientists must hesitate, before such formidable enigmas. ■“Where do we come from? From a nebula, originally round, said Laplace. But, why is it that those which we see, the least advanced in their evolution, never take this form ? The greater part of them are of a spiral shape,, with two, distinct branches It is also quite possible that the nebula of which this world is the issue was at the beginning, that is to say some milliards of years ago, of a like constitution. This question of spiral nebulae, is one which is greatly interesting to savants. In passing, over these speculations, for which our minds are not yet ripe, we come to a subject which is more accessible. Where are the nebulae ?

“UntiJ now, the greater part of astronomers, those who devote themselves to science, not romance, have admitted that all objects affected by our instruments were enclosed within a space clearly determined, and which is none other than the Milky Way. this immense formation, which represents in our eyes our universe, is said to contain not only about two million stars, but also all the stellar groups and all the nebulae. In fact, we have been convinced for some time that certain nebulae, such as Orion, or Aiidromede, form an integral part of the Milky Way. This is because we have been able to measure the distances. For the lesser nebulae the distances were unknown. and so the doubt has been permissible. “Some astronomers have supposed, as did Herschel at one time, that the apparent smallness of the nebulae and their feeble light were on account of the immense distances of these mysterious objects which one likens to a different universe than ours, and comparable to our Milky Wav. These conclusions appeared all the more legitimate when about ten years ago, according to the specialists in stellar matters, one could only attribute to our Milky Way some thousands of light years in diameter. Newcomb, in particular, said that a luminous ray, which moved at a speed of 300,000 kilometres a second, would take. a maximum c£ 15,000 to 16,000 years to cross our universe. So, generally speaking, the star clusters and nebulae appeared much further away. But, by applying relatively new methods for determining distance, Horrow Shapley, of Mount Wilson, definitely established in 1918 that our Milky Way showed much greater dimensions; in fac-t, no 1 fewer than 300,000 light years,

and the furthest away star-cluster which was examined took 200.000 years to reach us. It also appeared that the elements of our Milky Way were accessible to our instruments. There were still a few doubts, but these were left to the future to clear a wav.

“Although our .stellar period of AOO kilometres was a rarity, it was discovered that for many of the lessor spiral nebulae the speed was something like 1200 kilometres a second. This seemed to us as foreign to mu’ universe, represented by the Milky Way. Imt it v. as by no means the opinion of Khapley. This is rather a piquant remark to make, but it is the same astronomer who now brilliantly demonstrate.'; the inanity of his iirb. aifii inai.ion. “There exists an extremely small nebula in the heavens. It is invisible to the naked eye. and has been registered in the catalogue-.of I.)rover under the number of 6822. This obioot of sixteenth greatness looks like a reduction of those largo white patches known under the, name of .Magellan multitudes, and which shim.' on the edge of the Austral Milky Way. Through the telescope it looks like a lot of bilk? clusters mixed with many lesser nebulae, and as the stars which are visible in this limited rich! arc ha rely of the eighteenth greatness it w.is inferred that tins nesi m nebulae us.; an immense distamo away, Lai whether the dislaiice was greater i ban t hat of |he cluster at 226. 61)0 light years it is not possible to say. So simpler Ivor! to take up tins intoro c diug problem, ami

what i.lo on think ho. has discovered;' The celestial ohieel which answers to the number 6822 in the now catalogue of nebulae is to be found at a million of light years; that is to ray. the luminous ray which reaches ns at this moment when we arc contemplating this nebula lias been travelling for a million years. It is, therefore, not part of our

21 ilk v May, winch e call ear on i verse. It is apart I join ;l. and. like it. no doubt, travels across 1-lie vast nhv-sos of the heavens. Where is it going to:' Where are we going;:' Mv-terv ~f space! flow small we fee! in the fae<oi such ere a t pro!>!ems!“