WITHIN FIVE YEARS

Taranaki Daily News, 1 December 1934, Page 13 (Supplement)

WITHIN FIVE YEARS

ASTRONOMICAL PROGRESS

(By

the Rev. B. Dudley, F.R.A.S.)

Probably no branch of science has made so much advance during. recent years as astronomy. Most of the important discoveries which have been made have resulted in the widening of our stellar horizons. We have learned that the universe is a much vaster affair than was dreamed of by astronomers of last century. Within the past five years some interesting developments have taken place. In 1930 Dr. C. G. Abbot, secretary of the Smithsonian Institute, Washington, announced success in forecasting solar radiation variations and weather changes. It will be remembered that the National Geographical Society assisted in the carrying out of research upon which these forecasts' were based, even providing the funds required for the erection and maintenance of the solar observatory at Mount Brukkaros, South-west Africa. Should such forecasting become regularly possible it will be of valuable commercial advantage, as anyone can see. Quite recently, too, stations were planned to be built at Cambridge (England), Zurich, Florence, Italy, Beyrouth, Syria, Kodaikanal, South India, Canberra (Australia), Wellington (New Zealand) and other places for the purpose of undertaking a world-wide scientific agency with a view to the collation of facts and data relating to the solar atmosphere. A good deal depends upon a more perfect understanding of its activities. So far this ambitious enterprise has not been carried out on anything like a large scale. . About four years ago It was intimated on excellent authority that there are something like 30 million spiral nebulae within the reach of telescopic power. This means that there exist at least this number or universes other than our own, and more or less comparable with it, although, in the matter of size, our universe, or nebula as contained within the coils of the Milky Way, has the advantage over most of them. The only other having dimensions on such a scale as our own galactic system is the. one in the consellation of Andromeda. The 200-inch telescope in process of being erected is likely, it is thought, to reveal many millions more of these wonderful spirals. Incidentally, it may be stated, too, that our own galaxy is now known to contain about thirty thousand million gtsrs. These distinct nebulae have _ lately been studied from another point of view, and the result is that their speed has been ascertained to be eleven thousand miles per second on the average. There is, however, some possibility of error here. That movement in the spectroscope which indicates the rate of speed of these bodies, and known as the “red shift,” may or may not be altogether a function of velocity. Perhaps the 200inch mirror will help to determine whether there are other undiscovered factors in causing the shift. The third largest telescope in the world is undergoing construction at the Michigan University. Its speculum, 86J inches in diameter, has already been cast and was the work of the well-known Cornish glass works. Its thickness is nearly 17 inches at the outer edge, and the disc weighs 3J tons. It is interesting to note that, while the pouring of this mass of glass was completed in about four hours on April, S last, three months was required to cool it. Greenwich Observatory has just improved its’ equipment in the direction of replacing the old transit circle instrument J built by Sir George Airy in 1851, by a new 36-inch reflecting telescope fitted with a first rate spectroscopic apparatus. Such attachment will be invaluable to this instrument. The dome in which the telescope is to be housed is the gift of Mr. William Johnston Yapp. Greenwich does not, owing to its atmosphere, lend itself to work with the greatest possible telescopes; but the experts there know to make the best use of those of smaller range. It Is not more than five years since Sir Arthur Eddington stated that the universe is actually exploding, the galaxies scattering apart at an unimaginable speed. The rate of recession of the nebulae, as computed by him, has since been found to accord closely to Hubble’s determination of nebular velocity, mathematical calculations and actual observation thus agreeing very remarkably. Since Eddington’s announcement it has been suggested that perhaps the universe is subject to a process of alternate expansion and contraction, and that at the present time it is in one of its expansional phases. If so, it will be the privilege of astronomers in the remote future to announce the speed of contraction, when the universe will be found shrinking at such a tremendous rate as to create the impression that it is collapsing upon itself. By that time, however, the general public will have become so used to these movements as to accept them as common-place. Like the beating of the heart—systole, diastole the changes may mean the healthy maintenance of the stellar scheme. Only, in this case, one heart-beat will last for countless millions of years! In 1931 it was discovered that in the larger of the clouds of Magellan is a super-monster star whose light is variable in such manner or degree that it alternates in brilliancy from being 12,000 times as luminous as the sun to being 30,000 times as bright, the entire cycle of variability taking place within about four weeks. In the same or suer ceeding year it was made known that this “cloud” (nubecula major) also contains 214,000 stars, each of which is a hundred times more bright than the sun. It was also intimated that it possesses a gaseous nebula whose brightness is equal to fifteen million suns. Readers who are acquainted with the methods employed in the determination of the velocity of light will appreciate the new means adopted three or four years ago by which the calculations should be more exact than any previously used. A paragraph relating to this matter, taken from an American pub* lication runs: “Four days before his death, Dr. A. A. Michelson dictated from his sick bed the outline of the scientific paper which eventually will announce to the scientific world the most precise value of the velocity of light ever obtained. His experiments were made with a mile-long tube located near Santa Ana,. California. The tube is three feet in diameter and of a welded structure. Dr. F. G. Pease, his associate, announced that the result of the experiment is about the same as that obtained by Dr. Michelson’s experiment on Mount Wilson ; namely, 299,796 kilometres, or 186,285 miles, per B. Lyot, of Paris, announced in 1930 his conclusions respecting the surface of the moon, that it is covered with a thin layer of volcanic ash, and that Mercury and Mars appear to have a similar surface. If this, be correct, it is of greater importance than seems at first. Good reasons have recently been discovered for the suspicion that had been entertained for some years past that our stellar system, bounded by the Milky Way, is in a state of rotation, and that its period is about 150 million years.