Astronomical discovery

“ Nowhere in All The Annals of Astronomy Do We Find Such an Important Occasion; and Scarcely Is It Possible To Imagine a More Important Opportunity for Pointing Out, As Emphatically As Possible, the Importance Of That Problem, As at the Moment When Every Hope of Re-discovering, Among the Innumerable Little Stars of Heaven, That Mite of a Planet Which Had Been Lost To Sight for Nearly a Year, Depended Entirely on an Approximate Knowledge Of Its Orbit, Which Must Be Deduced From Those Scanty Observations. ”

“ In reviewing various types of astronomical discovery I have laid some stress upon the fact that they are, generally speaking, far from being accidental in character. A new planet does not “swim into our ken,” at any rate not usually, but is found only after diligent search, and then only by an investigator of acute vision, or other special qualifications. ”

“ Many of these are millions of times as great as the comparatively small fire-mist that would have evolved into our solar system.
A question has sometimes been asked as to the most important discovery in astronomy which has been made in the century that has just closed. If, by the most important discovery, we mean that which has most widely extended our knowledge of the Universe, I do not think there need be much hesitation in stating the answer. ”

“ It fortunately happens that astrophysical research is now at the very apex of its development, founded as it is upon many centuries of astronomical investigation, rejuvenated by the introduction into the observatory of all the modern devices of the physicist, and strengthened with instruments of truly extraordinary range and power. These instruments bring within reach experiments that are in progress on some minute region of the sun's disk, or in some star too distant even to be glimpsed with ordinary telescopes. ”

“ It will thus be evident that Herr Schwabe had the courage to enter upon a line of investigation which others had practically condemned as likely to lead nowhere, and that his discovery was quite contrary to expectation. It is a lesson to us that not even the most unlikely line of work is to be despised; for the outcome of Schwabe’s work was the first step in the whole series of discoveries which have gradually built up the modern science of Solar Physics, which occupies so deservedly large a part of the energies of, for instance, the great observatory attached to the University of Chicago. ”

“ Although the history of astronomy is the record of brilliant discoveries—of the labours of Copernicus, and of Kepler—of the telescopic achievements of Galileo, and the splendid theory of Newton—of the refined discovery of the aberration of light—of many other imperishable triumphs of intellect—yet this achievement of the organist at the Octagon Chapel occupies a totally different position from any other. There never before had been any historic record of the discovery of one of the bodies of the particular system to which the earth belongs. ”

“ It is even probable that space contains many darkened orbs, stars that may have risen in constellations to adorn the skies of prehistoric time—now cold, unseen, unknown. So far from dealing with an unvarying universe, it is safe to say that sidereal astronomy can advance only by the discovery of change. Observational science watches with untiring industry, and night hides few celestial events from the ardent scrutiny of astronomers. ”

“ It accordingly appeared that a planet possessing the mass which he had assigned, and moving in the orbit which his calculations had indicated, must indeed exist, though no eye had ever beheld any such body. Here was, indeed, an astonishing result. The mathematician sitting at his desk, by studying the observations which had been supplied to him of one planet, is able to discover the existence of another planet, and even to assign the very position which it must occupy, ere ever the telescope is invoked for its discovery. ”

“ Herschel’s achievement. It is a common experience in astronomy that an observer may fail to notice in a general scrutiny some phenomenon which he can see perfectly well when his attention is directed to it: when a man has made a discovery and others are told what to look for, they often see it so easily that they are filled with amazement and chagrin that they never saw it before. ”

“ The celestial sphere, therefore, as we now possess it, is not simply a collection of unmeaning names, associated with a group of stars in no way connected with them, which have been imposed at various epochs by capricious imagination, but in most instances, if not in all, they embody a history, which, if we could trace it, would probably lead us to astronomical facts, indicating the where and the when of their first introduction ”

“ For the present we must say decidedly that no case has been made out for paying serious attention to the influence of sun-spots on weather. Nevertheless, putting all this aside, there is quite enough of first-rate importance in the sequel to Schwabe’s discovery.
Let us review the facts in order. Most of us, though we may not have had the advantage of seeing an actual sun-spot through a telescope, have seen drawings or photographs of spots. ”

“ CHAPTER I URANUS AND EROS
Popular view of discovery.
Discovery is expected from an astronomer. The lay mind scarcely thinks of a naturalist nowadays discovering new animals, or of a chemist as finding new elements save on rare occasions; but it does think of the astronomer as making discoveries. The popular imagination pictures him spending the whole night in watching the skies from a high tower through a long telescope, occasionally rewarded by the finding of something new, without much mental effort. ”

“ The science is concerned with the heavenly bodies. The earth on which we live is, to all intents and purposes, one of these bodies, and, so far as its relations to the heavens are concerned, must be included in astronomy. The processes of measuring great portions of the earth, and of determining geographical positions, require both astronomical observations proper, and determinations made with instruments similar to those of astronomy. Hence geodesy may be regarded as a branch of practical astronomy. (S. N.)
History of Astronomy. ”

“ At certain times some of them approach near enough to the earth to merit the attention of those astronomers who are specially interested in determining the dimensions of the solar system. The observations are of such a nature that they can be made with considerable precision; they can also be multiplied to any extent that may be desired. Some of these little bodies have consequently a great astronomical future, inasmuch as they seem destined to indicate the true distance from the earth to the sun more accurately than Venus or than Mars. ”

“ To review a piece of history of this kind and note the mistakes of such men is certainly comforting, and need not in any way lessen our admiration. In the case of the investigators themselves, much may be set down to excitement in the presence of a possible discovery. Professor Sampson has provided us with a small but typical instance of this fact. When Adams had carried through all his computations for finding Neptune, and was approaching the actual place of the planet, he, “who could carry through fabulous computations without error,” for the first time wrote down a wrong figure. ”

“ There was a system of numbering in existence as well as of naming, but it was unadvisable to attach even a number to a planet until it was quite certain that the discovery was new, for otherwise there might be gaps created in what should be a continuous series by spurious discoveries being struck out. ”

“ A few years ago, when christening celestial formations was more in fashion than it is now, a man simply had to use a telescope for an evening or two on Mars or the moon, and spice the relation of his seeings with something in the way of novelty, when his name would be pretty certainly attached to an object and hung in the heavens for all time! ”

“ There is a tradition that, similarly, when the mighty Newton was approaching the completion of his calculations to verify the Law of Gravitation, his excitement was so great that he was compelled to assign to a friend the task of finishing them.
Finally, we may remark how the history of the discovery of Neptune again illustrates the difficulty of formulating any general principles for guiding scientific work. Sometimes it is well to follow the slightest clue, however imperfectly understood; at other times we shall do better to refuse such guidance. ”

“ The great mass of astronomical observations are almost exclusively of European origin, those which in later times have been made in other parts of the earth, are of a special character—they refer for the most part to the stars and are not numerous enough to furnish any general view, but here the question is of establishing a universal astronomy available for the whole earth, which, founded on the actual type of the phenomena, will become the result of science. ”

“ Astronomers who make a specialty of solar physics have, especially in this country, so many other duties, and their view is so often interrupted by clouds, that a continuous record of the spots on the sun and the changes they undergo is hardly possible. Perhaps one of the most interesting and useful pieces of astronomical work which an amateur can perform will consist of a record of the origin and changes of form of the solar spots and faculae. ”

“ Astronomy was long the leader among the sciences, and as such gave to the world trigonometry, in part logarithms, and Newton's dynamics. But though astronomical progress has by no means ceased, the accelerated growth of other sciences—first physics, then chemistry, and of late biology—has rendered it less conspicuous. The continued importance of astronomy is, however, well illustrated by the marvelous results of spectrum analysis, while to-day the study of nebulae and of the physics of the sun possesses the highest interest. ”

“ This eminent astronomer finds that stars with measurable proper motions—and therefore in all probability relatively near the earth—have mostly spectra of the solar type, and seem to cluster round “a point adjacent to the sun, in total disregard to the position of the Milky Way,” and that stars with little or no proper motion collect round the galactic plain. ”

“ Remark that in this case no peculiar appearance in the star suggested that it might be a comet or planet, as in the case of the discovery of Uranus. We are not unfair in ascribing the discovery to pure accident, although we must not forget that a careless observer might easily have missed it. ”

“ This splendid display concentrated the attention of astronomers on the theory of the movements of the little objects by which the display was produced. For the definite discovery of the track in which these bodies revolve, we are indebted to the labours of Professor Adams, who, by a brilliant piece of mathematical work, completed the edifice whose foundations had been laid by Professor Newton, of Yale, and other astronomers.
Meteors revolve around the sun in a vast swarm, every individual member of which pursues an orbit in accordance with the well-known laws of Kepler. ”

“ Several peoples who reached a high stage of civilisation at an early period claim to have made important progress in astronomy. Greek traditions assign considerable astronomical knowledge to Egyptian priests who lived some thousands of years B.C., and some of the peculiarities of the pyramids which were built at some such period are at any rate plausibly interpreted as evidence of pretty accurate astronomical observations ”

“ The Royal Observatory at Greenwich has always been, and is now, better equipped in some respects than any other observatory, as might be expected from its deservedly great reputation; but to possess the largest existing telescope has never been one of its ambitions. The instruments in which it takes most pride are remarkable for their steadiness and accuracy rather than for their size;not having suitable telescope at Greenwich and at that time the best telescope possessed by the observatory was not, in Airy’s opinion, large enough to detect the planet with certainty. ”

“ But the progress of investigation has changed all this, and has brought physical and natural science back to a position nearer to that of the old cosmogonies. Physical astronomy has shown that the constant emission of heat and light from the sun and other stars must have had a beginning, and is hurrying on toward an end, that the earth and its satellite the moon are receding from each other, and that even the spinning of our globe on its - 5 - axis is diminishing in rapidity. ”

“ How many of us are there who would cheerfully allow an astronomer to enter our house at any hour of the night to make observations in the coal-cellar! It says much, not only for Bradley’s fame, but for his personal attractiveness, that he should have secured this permission, and that there should be no record of any friction during these fifteen years. At the end of the whole series of nineteen years his conclusions were abundantly verified, and his second great discovery of nutation was established. ”

“ This question had indeed been asked even before the discovery of Uranus, by Bode, a young astronomer of Berlin; and for fifteen years he kept steadily in view this idea of finding a planet to fill the vacant interval. The search would be a very arduous one, involving a careful scrutiny, not perhaps of the whole heavens, but of a considerable portion of it along the Zodiac; too great for one would-be discoverer single-handed;Search for it. but in September 1800 Bode succeeded in organising a band of six German astronomers (including himself) for the purpose of conducting this search. ”