The Comet of 1884.

Waikato Times, Volume XXII, Issue 1839, 19 April 1884, Page 5 (Supplement)

The Comet of 1884.

[By E. P. Whitworth.]

Another comet is now engaging the attention of the astronomical world, and a few words on these mysterious wanderers in infinite and incomprehensible space, generally, and our coming visitor in particular, may not prove uninteresting ; especially if couched in popular language, so as to be easily understood by the general reader. Daring the visit of the comet of last year, much was written, and much appeared in the newspapers on the subject; but most of what did appear was from the pens of professional or amateur astronomers, and was not clearly intelligible, except to those who had, at the very least, a smattering of knowledge of the subject. A comet, according to the meaning of the term, is a hairy star. The word is derived from the Latin cometa ; or the Greek chometes from chome, coma, signifiying hair. But little is known of the nature, formation, or constitution of these errant stars ; yet, although theix movements through trackless space is of a totally different character to that of the planets round our sun, or of the fixed stars round the central sun of our solar system, still they obey certain prescribed rules which enable us, or rather enable astronomers, to calculate and f oretel with something like certainty, the lime and place of their re-appearance. Opinions of learned men differ with regard to the constitution of comets; some considering them as mere concentrations of subtle tenuous ether, vapour, or gas, while others believe them to be opaque, spherical, solid bodies — like our planets — or in fact, like our earth, only accompanied in every case by a train or tail of rarer matter, which varies somewhat in form and dimension in each instance, and enables us easily to distinguish one comet from another.

That the comets we see, belong to our own solar system, is certain, inasmuch as they perform their revolutions in elliptical orbits round our sun ; which ia, in faot, the focus, though not the centre of their orbits. It; is only during the period when a comet is approaching and receding from its perihelion — that is to say — when it is in that part of its orbit or path nearest the sun, that it is visible to us. After it has passed that, it departs into unknown regions, and disappears. If the human mind could bear the strain, if the human intellect could even only faintly and feebly grapple with the idea of the infinitude of time and space, if the human brain could conceive the meaning of the higher notation, of say, the third, fourth, fifth, or sixth powers of millions, it would be a curious matter of contemplation to reflect, or rather to speculate, on the numbers of miles one of these nomads of the heavens has travelled during its, let us say, billions of years of existence. The bare thought, the utter vastness and absolute incomprehensibility of the subject teaches us how insignificant in the scheme of creation is man and his little span of threescore and ten. In common terms, comets are described as tailed, bearded, or hairy, and at one time when they were looked upon as supernatural visitors sent to presage famine, pestilence, and death, it was thought that these various forms in which they appeared were their proper, normal, and unvarying shapes, having different prophetic msanings. But it is now known that these terms are to be used only in reference to the appearance of their attendant light, as they are observed in different positions in respect to the sun Thus when the comet is in one particular position in the heavens as regards the sun, the luminous train in which it is enveloped appears like a long streaming tail, which, as in the case of last year's comet, extends more or less across the firmament, and diverges or extends in breadth according to its length. Again, when the comet and sun are opposite, that is to say, when the earth is between them, the pomet, to us, appears as if immersed in its train, the light lo iking like a fringe or border of phosphorescent hair surround its body, and obtaining for it the popular and significant name of a blazing star. The comet now under consideration is confidently said to be the same as appeared seventy-two years since, or in 1812, when on July 29 Lh of that year it was first seen by M. Pons at Marseilles. It was also afterwards seen by Wisniewsky, the Russian astronomer, at NovoTchercask, a town on -the Eiver Don, in the Don Cossack territory of South Eussia, and is known amongst astronomers as the Pons comet. At the time of its appearance, it did not, although visible to the naked eye for about a week, create much general concern, as it was neither very large nor very bright. But it was viewed with great interest by astronomers and scientific men, who were enabled, by closely watching its movements, to prognosticate the period of iU leappearance. This time they fixed approximately at 72 years, aud that period navmg nearly elapsed, and the comet having been seen in Washington, U.S.A., in September l?,st, Mr. Ellery referred to it so long since as Nov. 15, as being about to make its appearance in i Australia and other part 3 of the Southern hemisphere toward the end o£ December, identifying it, as he did with the comet already named, and which is due about that time. As a matter of fact it will be above the horizon befoio that time, but as it will set with the sun until after the middle of the month, it will be invisible on account of the solar rays. The comet will reach ita perihelion sometime in January, and will, in all probability, be a striking object in the heavens, although there is no reason to balieve that it will afford anything like the resplendent phenomenonal spectacle afforded by that of la&t year. At present it cannot be stated with any degree of certainty what the precise track of the comet will be, nor as a matter of fact, i 3 it definitely known that it is Pon3 7 comet at all. Still, in view of the nearness of the periodicity, as set down by the great celebrated discoverer and observer Encke, there is, in the minds of European and American, and it may be added, our own astronomers, little, if any, doubt on the subject. It will, no doubt, be remembered by many of our readers, that when the comet of 1882 first showed itself in the heavens, it was prognosticated by some astronomers that, judging from its course, it would in all probability reappear about the end of the following jear, that it is to say, the year 1883, and not a little consternation was caused by the further propheoy that the chances were in favor of its either falling into the sun, and thereby burning up our planet in an excess of fervent heat, or that it would envelope up in its train, and either suffocate us by mephitic vapor, shrivel us up, or drown us by means of watery storm and tempest. It is unnecessary to say that none of these events have occurred, and it may be well to explain that according to Mr. Ellery, tho track apparently pursued by that comet waa due only to a disturbance in Ife orbit, caused by its" comparatively close proximity to the sun during its perihelion, the real orbit into which it reverted as it receded from its focus being one which carried it off so far into the remote realms of space as to prevent ita revisiting us for a period of not less than 3000 years.