So in the case of our sun, the danger of an outburst such as has affected the stars in the Northern Crown and Cygnus is small enough when we estimate it by comparing the number of such accidents with the total number of stars, but vanishes almost into nothingness when we note that no insulated star like our sun seems hitherto to have undergone one of these tremendous catastrophes.
But as regards the fate of worlds circling round suns which have suffered in this way, we can form but one opinion. Beyond all doubt, if such worlds existed and were inhabited when their central orb blazed forth with many hundred times its former lustre, all life must have perished from their surface. We may believe, as many do, that no conditions are too unlike those we are familiar with on earth to render life impossible; that the creatures subsisting in a world exposed to the most fiery heat or to the most intense cold are adapted as perfectly to the conditions under which they subsist as we are to the circumstances of terrestrial life. But even adopting this view, though it seems to accord ill with what we know of our own earth,—where life ceases towards the polar and over large tracts of the equatorial regions,—we could not believe that creatures thus adapted to the conditions prevailing around them could endure an entire change of those conditions. With the accessions of heat in the stars in Cygnus and the Crown, such change must inevitably have taken place. Therefore, as I think, we must regard the catastrophes affecting those remote suns as assuredly involving "The End of many Worlds."
Note.—What is stated in the latter portion of this chapter applies now only to the star in the Northern Crown; for the star in Cygnus has not faded into a small star, but into a small nebula! For the further history of this star, the reader is referred to my forthcoming treatise entitled, "Pleasant Ways in Science."
VI.
THE AURORA BOREALIS.
Among the objects in view, when the recent Polar expedition was fitted out, was the hope that during the winter of 1875-76 the scientific observers who accompanied the expedition might be able to study the Aurora Borealis under unusually favourable conditions. This hope was, as most of my readers doubtless know, disappointed. Few auroras were seen, and those seen were not remarkable either for brilliancy or for beauty of colour. Yet in the very disappointment of the hope which had been entertained on this subject there was very significant evidence respecting the aurora, as will presently be shown. The quiescence, at that time, of the forces which produce the auroral streamers had its meaning, and a very strange one.
The aurora is one of those phenomena of nature which are characterized by exceeding beauty, and sometimes by an imposing grandeur, but are unaccompanied by any danger, and indeed, so far as can be determined, by any influence whatever upon the conditions which affect our well-being. Comparing the aurora with a phenomenon akin to it in origin—lightning—we find in this respect the most marked contrast. Both phenomena are caused by electrical discharges; both are exceedingly beautiful. It is doubtful which is the more imposing so far as visible effects are concerned. When the auroral crown is fully formed, and the vault of heaven is covered with the auroral banners, waving hither and thither silently, now fading from view, anon glowing with more intense splendour, the mind is not less impressed with a sense of the wondrous powers which surround us than when, as the forked lightnings leap from the thundercloud, the whole heavens glow with violet light, and then sink suddenly into darkness. The solemn stillness of the auroral display is as impressive in its kind as the crashing peal of the thunderbolt. But there is a striking contrast between the feelings with which we regard the safe splendours of the aurora and the terrible glory of the lightning flash. One display we contemplate with the calmness engendered by absolute security; the other—no matter how little the fear of death may affect the reason—cannot be regarded without exciting the consciousness of danger. We witness in safety, so far as itself is concerned, the flash whose light illuminates the cloud masses above and around us, but for aught we know it may be the last we shall ever see, since no man killed by lightning ever saw the flash which brought his death.