ASTRONOMICAL NOTES FOR JUNE.

Wairarapa Age, Volume XXXII, Issue 3205, 3 June 1909, Page 3

ASTRONOMICAL NOTES FOR JUNE.

(By the Rev. K W. Fairclough. F.R.A.S.) On the 22nd the sun enters Cancer and winter begins, and the earth will soon be at her greatest distance from the sun. On the 4th the moon will be eclipsed, but the shadow will probably be off before she rises here. On the 17th there will be an annular eclipse of the sun, but as the central line of the eclipse will sweep over the North Pole we need not look for it in New Zealand.

On the 7th Mercury and Venus will be in conjunction and may be possibly detected soon after sunset. Venus will be a little south of the new moon on the 19th. During 1908, 117 minor planets were discovered. Dr Metcalf, of Taunton. U.S.A., secured 46. The practical English claim only one! Four of these bodies are now known to cross the orbit of Jupiter. It is regarded as settled that the fluctuations in the brightness of Eros, one of the planetoids passing between the earth and M*rs, depends on the phase angle. Jupiter's eighth moon, owing to its great distance frcm the planet, is regarded as of doubtful stability, and this adds to its scientific interest. It was proved during the year that the matter forming comets tails increases in the velocity of its out-. rush as it gets further from the nucleus. This may be taken to demonstrate a repelling force acting opposite to gravity. The force is probably light itself acting on matter divided into extremely fine particles. The discovery of variable stars goes on at a great rate. Last year no less that 171 were discovered. The President of the R.A.S., Mr H. F. Newall, in is retiring address advocated the theory that the sun is fed by matter being constantly captured and drawn in. The sun's outI .put of heat is 130,000 horse-power per square meter. On the theory of this heat being drawn from the interior of the sun by the rising of heated gas to the surface, there would be required a lawyer of gas 1.230 feet thick (at our atmospheric pressure) per second. This layer would have to rise, give off all its h*at, and get out of the way for the next layer in one second. As against this difficult supposition he suggested an indraught of meteoric matter at the rate of 4,000 million tons per second. The quantity seems large, but even the little earth would supply material for 50,000 years at that rate. The increase of the sun's mass would, of course, accelerate the earth and other planets in their orbits. But our year would be shortened by only one thousandth of a second and the change could not be detected during the time in which exact observations have been made. The study of ancient eclipses leaves an unexplained discrepancy in the moon's motions/and he thinks an increase in the attractive power of the sun would afford a solution. An intelligent reader of Croll's "Climate and Time," a work on the general theory, asks (1) What is the ! cause of the fluctuations in the eccentricity of the earth's orbit? (2) iWhy does ttie major axis remain unchanged? (1) The fluctuation is •due to the perturbation of the planets. From time to time the placets are grouped so as to have a special pull on the earth. In very long periods these pulls are ofien repeated, and the form of the orbit is changed. But there is that limit. I When the eccentricity has reached a I maximum of about fourteen millions [ of miles the pulls begin to operate as ' a corrective, and the orbit slowly ■ returns towards the circular form as iit is doing now. There is, however, | a limit on this side also, and the orbit never becomes absolutely circular'. 1 (2) The major axis of the orbit, that ! is the line joining the nearest and furthest points through the sun's ' centre, must remain constant. It ' is the one unalterable element in a ' planetary orbit. If it were to ! change the balance between the ! planet's mean victory and the sun's attriaction would be disturbed and the length of the year altered. As it is, when the orbit ovals and narrows the sun may be regarded as sliding down the major axis nearer to one end of the ellipse. One part of the orbit is then traversed by the planet at a greater speed that before; but another part is traversed at a reduced speed and the year remains the same. Some time ago we discussed a few of the aspects of the partial impact theory, but we left off with the actual collision. Now the most amazing thing about a blaze star is the rapidity with which it fades. That the new star should appear in the sky and within a few days be so bright as to be seen in daylight is very remarkable.- Supposing a faint telescopic Htar to have been there prior to the outbreaks, 'the increase of lustre would still be something like a hundred thousand-fold. But there may have been no luminous star there at all, and yet in a few days the most spendid body known in the universe appears. This is truly astonishing, but it is only a commonplace thing beside what follows. In seventeen months this splendid luminary has sunk into invisibility! We refer heie to Tycho's star of 1572 There have, however, been many others, and though they were not so splendid, they may, owing to greater distance, have been equalled or exceeded by Tycho's. But nothing is known of their dstance except that it is of the stellar order. There is no doubt that many of these objects have exceeded the splendour of the sun thousands of times. Yet, though suns shine for millions of years, these temporary ( stars begin to fade rapidly after a week or two [and BJon disapfear. Nothing in the whole heavens calls so loudly to human intelligence for an explanation, and we know of no answer that can compare for simI'pl'city and probability 'with that | offered by Professor Bickerton. He supposes a partial collision to have taken place between two bodies, possibly dark and cold, but sunlike in mass. These bodies, each with a velocity of several hundreds of miles per second, meet, clip a contionent out of each other and pass on. The two clips stop each other's motion and turn the work. or motion into heat. Here then you have a vast mass of matter, say, equal to the sun, with an energy of ! heat not only sufficien to turn it all

into vapour, but into unimaginably hot vapour—superheated and explosive beyond arithmetic. The outrush of the explosion may be at the rate of, say, a million miles an hour m every direction. In four days globes of gas would fill the erbit of the earth, ion twenty days it would fill that of Jupiter. Of course the outrush will be gradually slowed down by the nebula's own;gravit> that of the two parent bodies, which would be speedily overtaken and enveloped. Still the energy of, the explosion would be so tremendous that the centrifugal rush would not be speedily arrested. The expansion would continue for many months at a diminishing rate. Now it will be obvious that for the first few days this new born nebula will increase in splendour as seen from a great distance; for its luminous surface is growing rapidly. That would account for the amazing rise of a blaze star Beyond a certain point the expansion would be at the expense of the surface luminosity. The process began by turning work, or motion, into heat. Now the process continues by turning the heat I back into work, or motion. The \ work represented in expanding the original dense mass into a nebula with a diameter of many thousand millions of miles is very great, and it is borrowed from the store of heat. This accounts for a decline in lustre. Besides that, the nebul a has become unthinkably tenuous, and though still very hot, has no longer a sunlike surface. This expansion of the exploded clips from the impacting bodies therefore explains the swift rise in the luminosity of a temporary sta r , and the more gradual, but still rapid, decline of the light. These are' the things that cried aloud Jfor explanation, and they seem to have an explanation here, so simple and clear that it is of itself a kind of proof. Proofs of another sort are, however, not wanting. The evidence of the spectrascope is not inconsistent with the theory, and in several particulars seem to support it. In one of two cases a globular nebular has been detected in the place where the star shone and disappeared. That is a very assuring fact. Then there are multitudes of double stars—stars revolving round their cantre of gravity and so close together that only powerful telescopes can separate them. These, Professor Bickerton says, tell a story of a kiss and a wedding: Gin a body meet a body, •Flying thro' the sky; Gin a body kiss ahody, Need a body fly? But variable stars, of which there are thousands, and especially those which are found in pairs, are claimed by our theorist as stars wounded by impact, and with one side brighter than the other. ; We have stated the case roughly, and for the popular reader. For the renfinements, the physics and chemistry of the great explosion, the reader is referred to the ingenious chapters on "Selective Maticular Escape" in the professor's works. The explanation of the rise and decline of the blaze star gives the present writer considerable mental satisfaction but he is full of obstacles as regards some of other parts of the theory. They will keep till next month.