Myths and Marvels of Astronomy

Let us now imagine that gradually, by becoming more closely observant than they had been, by combining together to make more complete observations, and above all by preserving the records of observations made by successive generations, these creatures began to obtain clearer ideas respecting their world and the surrounding regions of space. They would find evidence that the fruit on which they lived had not been formed precisely as they knew it, but had undergone processes of development. The distressing discovery would be made that this development could not possibly have taken place in a few seconds, but must have required many hours, nay, even several of those enormous periods called by us days.

This, however, would only be the beginning of their troubles. Gradually the more advanced thinkers and the closest observers would perceive that not only had their world undergone processes of development, but that its entire mass had been formed by such processes—that in fact it had not been created at all, in the sense in which they had understood the word, but had grown. This would be very dreadful to these creatures, because they would not readily be able to dispossess their minds of the notion that they were the most important beings in the universe, their domain of space coextensive with the universe, the duration of their world coextensive with time.

But passing over the difficulties thus arising, and the persecution and abuse to which those would be subjected who maintained the dangerous doctrine that their fruit home had been developed, not created, let us consider how these creatures would regard the question of other worlds than their own. At first they would naturally be unwilling to admit the possibility that other worlds as important as their own could exist. But if after a time they found reason to believe that their world was only one of several belonging to a certain tree system, the idea would occur to them, and would gradually come to be regarded as something more than probable, that those other fruit worlds, like their own, might be the abode of living creatures. And probably at first, while as yet the development of their own world was little understood, they would conceive the notion that all the fruits, large or small, upon their tree system were in the same condition as their own, and either inhabited by similar races or at least in the same full vigour of life-bearing existence. But so soon as they recognised the law of development of their own world, and the relation between such development and their own requirements, they would form a different opinion, if they found that only during certain stages of their world's existence life could exist upon it. If, for instance, they perceived that their fruit world must once have been so bitter and harsh in texture that no creatures in the least degree like themselves could have lived upon it, and that it was passing slowly but surely through processes by which it would become one day dry and shrivelled and unable to support living creatures, they would be apt, if their reasoning powers were fairly developed, to inquire whether other fruits which they saw around them on their tree system were either in the former or in the latter condition. If they found reason to believe certain fruits were in one or other of these stages, they would regard such fruits as not yet the abode of life or as past the life-supporting era. It seems probable even that another idea would suggest itself to some among their bolder thinkers. Recognising in their own world in several instances what to their ideas resembled absolute waste of material or of force, it might appear to them quite possible that some, perhaps even a large proportion, of the fruits upon their tree were not only not supporting life at the particular epoch of observation, but never had supported life and never would—that, through some cause or other, life would never appear upon such fruits even when they were excellently fitted for the support of life. They might even conceive that some among the fruits of their tree had failed or would fail to come to the full perfection of fruit life.

Looking beyond their own tree—that is, the tree to which their own fruit world belonged—they would perceive other trees, though their visual powers might not enable them to know whether such trees bore fruit, whether they were in other respects like their own, whether those which seemed larger or smaller were really so, or owed their apparent largeness to nearness, or their apparent smallness to great distance. They would be apt perhaps to generalise a little too daringly respecting these remote tree systems, concluding too confidently that a shrub or a flower was a tree system like their own, or that a great tree, every branch of which was far larger than their entire tree system, belonged to the same order and bore similar fruit. They might mistake, also, in forgetting the probable fact that as every fruit in their own tree system had its own period of life, very brief compared with the entire existence of the fruit, so every tree might have its own fruit-bearing season. Thus, contemplating a tree which they supposed to be like their own in its nature, they might say, 'Yonder is a tree system crowded with fruits, each the abode of many myriads of creatures like ourselves:' whereas in reality the tree might be utterly unlike their own, might not yet have reached or might long since have passed the fruit-bearing stage, might when in that stage bear fruit utterly unlike any they could even imagine, and each such fruit during its brief life-bearing condition might be inhabited by living beings utterly unlike any creatures they could conceive.

Yet again, we can very well imagine that the inhabitants of our fruit world, though they might daringly overleap the narrow limits of space and time within which their actual life or the life of their race was cast, though they might learn to recognise the development of their own world and of others like it, even from the very blossom, would be utterly unable to conceive the possibility that the tree itself to which their world belonged had developed by slow processes of growth from a time when it was less even than their own relatively minute home.

Still less would it seem credible to them, or even conceivable, that the whole forest region to which they belonged, containing many orders of trees differing altogether from their own tree system, besides plants and shrubs, and flowers and herbs (forms of vegetation of whose use they could form no just conception whatever), had itself grown; that once the entire forest domain had been under vast masses of water—the substance which occasionally visited their world in the form of small drops; that such changes were but minute local phenomena of a world infinitely higher in order than their own; that that world in turn was but one of the least of the worlds forming a yet higher system; and so on ad infinitum. Such ideas would seem to them not merely inconceivable, but many degrees beyond the widest conceptions of space and time which they could regard as admissible.

Our position differs only in degree, not in kind, from that of these imagined creatures, and the reasoning which we perceive (though they could not) to be just for such creatures is just for us also. It was perfectly natural that before men recognised the evidences of development in the structure of our earth they should regard the earth and all things upon the earth and visible from the earth as formed by special creative acts precisely as we see them now. But so soon as they perceived that the earth is undergoing processes of development and has undergone such processes in the past, it was reasonable, though at first painful, to conclude that on this point they had been mistaken. Yet as we recognise the absurdity of the supposition that, because fruits and trees grow, and were not made in a single instant as we know them, therefore there is no Supreme Being, so may we justly reject as absurd the same argument, enlarged in scale, employed to induce the conclusion that because planets and solar systems have been developed to their present condition, and were not created in their present form, therefore there is no Creator, no God. I do not know that the argument ever has been used in this form; but it has been used to show that those who believe in the development of worlds and systems must of necessity be atheists, an even more mischievous conclusion than the other; for none who had not examined the subject would be likely to adopt the former conclusion, but many might be willing to believe that a number of their fellow-men hold obnoxious tenets, without inquiring closely or at all into the reasoning on which the assertion had been based.

But it is more important to notice how our views respecting other worlds should be affected by those circumstances in the evidence we have, which correspond with the features of the evidence on which the imagined inhabitants of the fruit world would form their opinion. It was natural that when men first began to reason about themselves and their home they should reject the idea of other worlds like ours, and perhaps it was equally natural that when first the idea was entertained that the planets may be worlds like ours, men should conceive that all those worlds are in the same condition as ours. But it would be, or rather it is, as unreasonable for men to maintain such an opinion now, when the laws of planetary development are understood, when the various dimensions of the planets are known, and when the shortness of the life-supporting period of a planet's existence compared with the entire duration of the planet has been clearly recognised, as it would be for the imagined inhabitants of a small fruit on a tree to suppose that all the other fruits on the tree, though some manifestly far less advanced in development and others far more advanced than their own, were the abode of the same forms of life, though these forms were seen to require those conditions, and no other, corresponding to the stage of development through which their own world was passing.

Viewing the universe of suns and worlds in the manner here suggested, we should adopt a theory of other worlds which would hold a position intermediate between the Brewsterian and the Whewellite theories. (It is not on this account that I advocate it, let me remark in passing, but simply because it accords with the evidence, which is not the case with the others.) Rejecting on the one hand the theory of the plurality of worlds in the sense implying that all existing worlds are inhabited, and on the other hand the theory of but one world, we should accept a theory which might be entitled the Paucity of Worlds, only that relative not absolute paucity must be understood. It is absolutely certain that this theory is the correct one, if we admit two postulates, neither of which can be reasonably questioned—viz., first, that the life-bearing era of any world is short compared with the entire duration of that world; and secondly, that there can have been no cause which set all the worlds in existence, not simultaneously, which would be amazing enough, but (which would be infinitely more surprising) in such a way that after passing each through its time of preparation, longer for the large worlds and shorter for the small worlds, they all reached at the same time the life-bearing era. But quite apart from this antecedent probability, amounting as it does to absolute certainty if these two highly probably postulates are admitted, we have the actual evidence of the planets we can examine—that evidence proving incontestably, as I have shown elsewhere, that such planets as Jupiter and Saturn are still in the state of preparation, still so intensely hot that no form of life could possibly exist upon them, and that such bodies as our moon have long since passed the life-bearing stage, and are to all intents and purposes defunct.

But may we not go farther? Recognising in our own world, in many instances, what to our ideas resembles waste—waste seeds, waste lives, waste races, waste regions, waste forces—recognising superfluity and superabundance in all the processes and in all the works of nature, should it not appear at least possible that some, perhaps even a large proportion, of the worlds in the multitudinous systems peopling space, are not only not now supporting life, but never have supported life and never will? Does this idea differ in kind, however largely to our feeble conceptions it may seem to differ in degree, from the idea of the imagined creatures on a fruit, that some or even many fruits excellently fitted for the support of life might not subserve that purpose? And as those creatures might conceive (as we know) that some fruits, even many, fail to come to the full perfection of fruit life, may not we without irreverence conceive (as higher beings than ourselves may know) that a planet or a sun may fail in the making? We cannot say that in such a case there would be a waste or loss of material, though we may be unable to conceive how the lost sun or planet could be utilised. Our imagined insect reasoners would be unable to imagine that fruits plucked from their tree system were otherwise than wasted, for they would conceive that their idea of the purpose of fruits was the only true one; yet they would be altogether mistaken, as we may be in supposing the main purpose of planetary existence is the support of life.

In like manner, when we pass in imagination beyond the limits of our own system, we may learn a useful lesson from the imagined creatures' reasoning about other tree systems than that to which their world belonged. Astronomers have been apt to generalise too daringly respecting remote stars and star systems, as though our solar system were a true picture of all solar systems, the system of stars to which our sun belongs a true picture of all star systems. They have been apt to forget that, as every world in our own system has its period of life, short by comparison with the entire duration of the world, so each solar system, each system of such systems, may have its own life-bearing season, infinitely long according to our conceptions, but very short indeed compared with the entire duration of which the life-bearing season would be only a single era.

Lastly, though men may daringly overleap the limits of time and space within which their lives are cast, though they may learn to recognise the development of their own world and of others like it even from the blossom of nebulosity, they seem unable to rise to the conception that the mighty tree which during remote æons bore those nebulous blossoms sprang itself from cosmical germs. We are unable to conceive the nature of such germs; the processes of development affecting them belong to other orders than any processes we know of, and required periods compared with which the inconceivable, nay, the inexpressible periods required for the development of the parts of our universe, are as mere instants. Yet have we every reason which analogy can afford to believe that even the development of a whole universe such as ours should be regarded as but a minute local phenomenon of a universe infinitely higher in order, that universe in turn but a single member of a system of such universes, and so on, even ad infinitum. To reject the belief that this is possible is to share the folly of beings such as we have conceived regarding their tiny world as a fit centre whence to measure the universe, while yet, from such a stand-point, this little earth on which we live would be many degrees beyond the limits where for them the inconceivable would begin. To reject the belief that this is not only possible, but real, is to regard the few short steps by which man has advanced towards the unknown as a measurable approach towards limits of space, towards the beginning and the end of all things. Until it can be shown that space is bounded by limits beyond which neither matter nor void exists, that time had a beginning before which it was not and tends to an end after which it will exist no more, we may confidently accept the belief that the history of our earth is as evanescent in time as the earth itself is evanescent in space, and that nothing we can possibly learn about our earth, or about the system it belongs to, or about systems of such systems, can either prove or disprove aught respecting the scheme and mode of government of the universe itself. It is true now as it was in days of yore, and it will remain true as long as the earth and those who dwell on it endure, that what men know is nothing, the unknown infinite.

VI.

SUNS IN FLAMES

In November 1876 news arrived of a catastrophe the effects of which must in all probability have been disastrous, not to a district, or a country, or a continent, or even a world, but to a whole system of worlds. The catastrophe happened many years ago—probably at least a hundred—yet the messenger who brought the news has not been idle on his way, but has sped along at a rate which would suffice to circle this earth eight times in the course of a second. That messenger has had, however, to traverse millions of millions of miles, and only reached our earth November 1876. The news he brought was that a sun like our own was in conflagration; and on a closer study of his message something was learned as to the nature of the conflagration, and a few facts tending to throw light on the question (somewhat interesting to ourselves) whether our own sun is likely to undergo a similar mishap at any time. What would happen if he did, we know already. The sun which has just met with this disaster—that is, which so suffered a few generations ago—blazed out for a time with several hundred times its former lustre. If our sun were to increase as greatly in light and heat, the creatures on the side of our earth turned towards him at the time would be destroyed in an instant. Those on the dark or night hemisphere would not have to wait for their turn till the earth, by rotating, carried them into view of the destroying sun. In much briefer space the effect of his new fires would be felt all over the earth's surface. The heavens would be dissolved and the elements would melt with fervent heat. In fact no description of such a catastrophe, as affecting the night half of the earth, could possibly be more effective and poetical than St. Peter's account of the day of the Lord, coming 'as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein being burned up;' though I imagine the apostle would have been scarce prepared to admit that the earth was in danger from a solar conflagration. Indeed, according to another account, the sun was to be turned into darkness and the moon into blood, before that great and notable day of the Lord came—a description corresponding well with solar and lunar eclipses, the most noteworthy 'signs in the heavens,' but agreeing very ill with the outburst of a great solar conflagration.

Before proceeding to inquire into the singular and significant circumstances of the recent outburst, it may be found interesting to examine briefly the records which astronomy has preserved of similar catastrophes in former years. These may be compared to the records of accidents on the various railway lines in a country or continent. Those other suns which we can stars are engines working the mighty mechanism of planetary systems, as our sun maintains the energies of our own system; and it is a matter of some interest to us to inquire in how many cases, among the many suns within the range of vision, destructive explosions occur. We may take the opportunity, later, to inquire into the number of cases in which the machinery of solar systems appears to have broken down.

The first case of a solar conflagration on record is that of the new star observed by Hipparchus some 2000 years ago. In his time, and indeed until quite recently, an object of this kind was called a new star, or a temporary star. But we now know that when a star makes its appearance where none had before been visible, what has really happened has been that a star too remote to be seen has become visible through some rapid increase of splendour. When the new splendour dies out again, it is not that a star has ceased to exist; but simply that a faint star which had increased greatly in lustre has resumed its original condition. Hipparchus's star must have been a remarkable object, for it was visible in full daylight, whence we may infer that it was many times brighter than the blazing Dog-star. It is interesting in the history of science, as having led Hipparchus to draw up a catalogue of stars, the first on record. Some moderns, being sceptical, rejected this story as a fiction; but Biot examining Chinese Chronicles32 relating to the times of Hipparchus, finds that in 134 b.c. (about nine years before the date of Hipparchus's catalogue) a new star was recorded as having appeared in the constellation Scorpio.

The next new star (that is, stellar conflagration) on record is still more interesting, as there appears some reason for believing that before long we may see another outburst of the same star. In the years 945, 1264, and 1572, brilliant stars appeared in the region of the heavens between Cepheus and Cassiopeia. Sir J. Herschel remarks, that, 'from the imperfect account we have of the places of the two earlier, as compared with that of the last, which was well determined, as well as from the tolerably near coincidence of the intervals of their appearance, we may suspect them, with Goodricke, to be one and the same star, with a period of 312 or perhaps of 156 years.' The latter period may very reasonably be rejected, as one can perceive no reason why the intermediate returns of the star to visibility should have been overlooked, the star having appeared in a region which never sets. It is to be noted that, the period from 945 to 1264 being 319 years, and that from 1264 to 1572 only 308 years, the period of this star (if Goodricke is correct in supposing the three outbursts to have occurred in the same star) would seem to be diminishing. At any time, then, this star might now blaze out in the region between Cassiopeia and Cepheus, for more than 304 years have already passed since its last outburst.

As the appearance of a new star led Hipparchus to undertake the formation of his famous catalogue, so did the appearance of the star in Cassiopeia, in 1572, lead the Danish astronomer Tycho Brahe to construct a new and enlarged catalogue. (This, be it remembered, was before the invention of the telescope.) Returning one evening (November 11, 1572, old style) from his laboratory to his dwelling-house, he found, says Sir J. Herschel, 'a group of country people gazing at a star, which he was sure did not exist an hour before. This was the star in question.'

The description of the star and its various changes is more interesting at the present time, when the true nature of these phenomena is understood, than it was even in the time when the star was blazing in the firmament. It will be gathered from that description and from what I shall have to say farther on about the results of recent observations on less splendid new stars, that, if this star should reappear in the next few years, our observers will probably be able to obtain very important information from it. The message from it will be much fuller and more distinct than any we have yet received from such stars, though we have learned quite enough to remain in no sort of doubt as to their general nature.

The star remained visible, we learn, about sixteen months, during which time it kept its place in the heavens without the least variation. 'It had all the radiance of the fixed stars, and twinkled like them; and was in all respects like Sirius, except that it surpassed Sirius in brightness and magnitude.' It appeared larger than Jupiter, which was at that time at his brightest, and was scarcely inferior to Venus. It did not acquire this lustre gradually, but shone forth at once of its full size and brightness, 'as if,' said the chroniclers of the time, 'it had been of instantaneous creation.' For three weeks it shone with full splendour, during which time it could be seen at noonday 'by those who had good eyes, and knew where to look for it.' But before it had been seen a month, it became visibly smaller, and from the middle of December 1572 till March 1574, when it entirely disappeared, it continually diminished in magnitude. 'As it decreased in size, it varied in colour: at first its light was white and extremely bright; it then became yellowish; afterwards of a ruddy colour like Mars; and finished with a pale livid white resembling the colour of Saturn.' All the details of this account should be very carefully noted. It will presently be seen that they are highly characteristic.