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quantity of invisible aqueous vapor that abode of pleasantness, a sort of paradise the spectroscopist can recognize the bands among the planet-worlds. There exists, we of this vapor in the planet's spectrum. are told, in that distant world, a perennial
Even more perplexing is the circum- spring, "A striking display of the benefistance that the cloud-masses should form cence of the Creator," says Admiral themselves into zones. We can not get
We can not get Smyth; "for the Jovian year contains rid of this difficulty by a mere reference to twelve mundane years; and if there were the planet's rapid rotation, unless we are a proportionate length of winter, that cold prepared to show how this rotation is to season would be three of the earthly years act in forcing the cloud-masses to become in length and tend to the destruction of true belts. The whole substance of Jupi- vegetable life.” ter and his whole atmosphere must take Even those who have denied that Jupart in his rotation, and to suppose that piter can be the abode of life, and have aqueous vapor raised from his oceans formed altogether unfavorable ideas of his would be left behind in the upper air like condition, have pictured him nevertheless the steam from a railway engine, is to make as the scene of continual calm, though the a mistake resembling that which caused calm is, according to their view, the calm Tycho Brahé to deny the rotation of the of gloom and desolation. They recognize earth, because bodies projected into the in Jupiter an eternal winter rather than a air are not left behind by the rotating earth. perpetual spring. Whewell, for example, Nor is it conceivable that belts which vary in that once famous work the Plurality of remarkably, from time to time, in position Worlds, maintained that if living creatures and extent, should be formed by sun-rais- exist at all in Jupiter, they must be wretched clouds in the Jovian atmosphere, if the ed gelatinous monsters, languidly floating planet's surface is divided into permanent about in icy seas. According to him Julands and seas.
piter is but a great globe of ice and water But we are thus led to consider a cir- with perhaps a cindery nucleus, a glacial cumstance which, as it appears to us, dis- planet, with no more vitality in it than an poses finally of the idea that in the cloud- iceberg. rings of Jupiter we have to deal with phe- But when we begin to examine the renomena resembling those presented by our cords of observers, and to consider them own earth.
with due reference to the vast proportions We are too apt in studying the celestial of the planet, we recognize the fact that objects to forget that where all seems at whatever may be Jupiter's unfitness to be nearly perfect rest, there may be processes the abode of life, it is not of an excess of of the utmost activity,—nay, rather of the stillness that his inhabitants (if he have utmost violence,-taking place as it were any) can justly make complaint Setting under our very eyes, and yet not percepti- aside the enormous activity of which the ble save to the eye of reason. Looking at mere existence of the belts affords evidence, Jupiter, under his ordinary aspect, even in and even regarding such phenomena as the the finest telescope, one would feel certain formation of a disappearance of a new belt that a general calm prevailed over his in two or three hours as merely indicative mighty globe. The steadfast equatorial of heavy rainfalls or of the condensation of ring, and the straight and sharply defined large masses of invisible aqueous vapor inbands over either hemisphere, suggest cer- to clouds,—there have been signs on more tainly no idea of violent action. And occasions than one, of Jovian hurricanes when some feature in a belt is seen to blowing persistently for several weeks tochange slowly in figure,—or rather, when gether at a rate compared with which the at the end of a certain time it is found to velocity of our fiercest tornadoes seems have so changed, for no eye can follow utterly insignificant. During the year such changes as they proceed,--we are 1860, a rift in one of the Jovian cloud-belts not prepared to recognize in the process behaved in such a way as to demonstrate the evidence of disturbances compared the startling fact that a hurricane was with which the fiercest hurricanes that raging over an extent of Jovian territory have ever raged on earth are as mere sum- equalling the whole surface of our earth, at mer zephyrs.
a rate of fully 150 miles per hour. It is Indeed the planet Jupiter has been se- not too much to say that a hurricane of lected even by astronomers of repute as an like velocity on our earth would destroy
every building in the territory over which ed to merit. Several, indeed, of our leadit raged, would uproot the mightiest foresting astronomers were disposed to deny trees, and would cause in fact universal that any thing unusual was in progress, desolation. At sea no ship that man ever though none asserted definitely that they made could withstand the fury of such a based this opinion on a careful re-examinstorm for a single minute. And yet this ation of the planet's face. But quite retremendous Jovian hurricane continued to cently one of the most eminent of our rage with unabated fury for at least six modern observers, Mr. Lassell, lately weeks, or for fully one hundred Jovian president of the Royal Astronomical Sodays.
ciety—(having been led to observe the But during the last two or three years planet by the fact that certain phenomena a change of so remarkable a nature has of interest in connection with the satellite passed over Jupiter as to imply the exist- system are now in progress,) found his attence of forces even more energetic than tention attracted by the marvelous beauty those at work in producing atmospheric of the colors presented by Jupiter's belts. changes.
After describing the appearances he had In the autumn of 1870, Mr. Browning intended to observe in the first instance, (the eminent optician and observer) called he proceeds, " But this was not the phethe attention of astronomers to the fact nomenon which struck me most in this that the great equatorial zone, usually, as rare and exquisite view of Jupiter. I must we have said, of a creamy white color, had acknowledge that I have hitherto been assumed a decidedly orange tint. At the inclined to think that there might be some same time it had become much less uni- exaggeration of the colored views I have form in outline and sundry peculiarities in lately seen of the planet; but this properits appearance could be recognized, which ty of the disk, in the view I am describing, have been severally compared to port-holes, was so unmistakable that my skepticism is pipe-bowls and stems, oval moldings, and at last beginning to yield.” 'Nor will this other objects of an uncelestial nature. statement be thought to express more Without 'entering into descriptions which than the truth, when we add that in the could only be rendered intelligible by picture accompanying his paper, Mr. Lasmeans of a series of elaborate illustrations, sell presented the equatorial zone as brownlet it suffice to say that the bright edges of orange, and three neighboring dark zones the belts bordering on this ruddy equato- as purple; one of the interinediate light rial zone seemed to be frayed and torn like belts being pictured as of a light olivethe edges of storm clouds, and that the green. knots and projections thus formed often Let us compare these observations made extended so far upon the great orange in our brumous latitudes, with those efzone, from both sides, as almost to break fected by Father Secchi with the fine it up into separate parts.
equatorial of the Roman Observatory. Now without inquiring into the particu- “ During the fine evenings of this month," lar form of action to which these remark- he wrote last February, " Jupiter has preable changes were due, we can see at once sented a wonderful aspect. The equatothat they implied processes of extreme rial band, of a very pronounced rose color, energy. For, every one of the projections was strewn with a large number of yellowand knots, the seeming frayed edges of ish clouds. Above and below this band, narrow cloud-streaks, had, in reality, an there were many very fine zones, with othextent exceeding the largest of our terres- ers strongly marked and narrow, which retrial countries. Yet their aspect, and in- sembled stretched threads. The blue and deed the whole aspect of the ruddy belt, yellow colors formed a remarkable conwhose extent far exceeded the whole sur- trast with the red zone, a contrast doubtface of our earth, changed obviously from less increased by a little illusion. . The night to night.
surface of the planet is actually so differStrangely enough, these interesting ob- ent from that which I have formerly seen, servations, though they were presently that there is room for the study of the confirmed by several well-known stu
stu- planet's meteorology." dents of the heavens, did not attract It appears to us that when these rethat full attention from the senior as- markable changes are considered in comtronomers of the day which they appear
bination with the circumstance that on d priori grounds we should expect the sun half as broad as it is long. As no less to have very little influence on the condi- than fourteen years and a half separate the tion of the planet's atmosphere, the idea Saturnian summer and winter, we might can not but be suggested that the chief fairly expect that the sun's action would source of all this energy resides in the have time to exert itself. In particular, planet itself. The idea may seem start- we might fairly expect the great equatoling at a first view, but when once enter- rial zone to be displaced; for our terrestained, many arguments will be found to trial zone of calms or “doldrums” travels present themselves in its favor.
north and south of the equator as the sun For instance, it does not seem to have shifts northward and southward of the cebeen noticed, heretofore, as a very re- lestial equator, accomplishing in this way markable circumstance if the Jovian belts a range of no less than 3000 miles. But are sun-raised, that they pass round to the the Saturnian equatorial zone is not disnocturnal half of Jupiter and reappear placed at all during the long Saturnian again, with the same general features as year. It remains always persistently equabefore, and this often for weeks at a torial ! Nothing could be more easy than stretch. Even that remarkable feature the detection of its change of place if it whose changes led to the conclusion that followed the sun; yet no observer has ever mighty hurricanes were in progress, yet suspected the slightest degree of systematchanged continuously and regularly dur. ic change corresponding with the changes ing the Jovian nights as well as during the of the Saturnian seasons. Or rather, it is Jovian days, for one hundred such days absolutely certain that no such change in succession. This is perfectly intelligi- takes place. ble if the seat of disturbance is in the It appears, then, that night and day planet itself, but it is perfectly inexplicable, and summer and winter, are alike withou (as it seems to us,) if the sun occasions all influence on the Jovian and Saturnian these meteorological changes in Jupiter, cloud zones. Can it reasonably be quesas he occasions all the changes which take tioned that, this being the case, we must place in our earth's atmosphere. The al- look for the origin of the cloud zones in ternation of day and night, which is one these planets themselves, and not in the of the most potent of all the circumstances solar orb, whose action must needs be affecting the earth's meteorological condi- largely influenced by the alternation of tion, appears to have no effect whatever night and day and of the seasons ? on the condition of Jupiter's atmosphere ! But further, we find that a circumstance
Now, as respects the alternation of sum- which had seemed perplexing when we mer and winter, we can form no satisfac- compared the Jovian belts with terrestrial tory opinion in Jupiter's case, because he trade-wind zones, finds an explanation at has no seasons worth mentioning. For once when we regard the belts as due to instance, in latitudes on Jupiter corre- some form of action exerted by the planet sponding to our own, the difference be- itself. For let us suppose that streams of tween extreme winter and extreme sum- vapor are poured upwards to vast heights mer corresponds to the difference between and with great velocity from the true surthe warmth on March 12th and March face of the planet. Then such streams 28th, or between the warmth on Septem- starting from the surface with the rotationber 15 and on September 31st. Yet we al movement there prevailing, would be are not without evidence as to seasonal carried to regions where (owing to increase meteorological effects in the case of the of distance from the centre) the movement sun's outer family of planets. Saturn, a due to the planet's rotation would be greatbelted planet like Jupiter, and in all oth- er. They would thus be caught by the er respects resembling him so far as tele- more swiftly-moving upper air and carried scopic study can be trusted, has seasons forwards, the modus operandi being the reeven more markedly contrasted than those verse of that observed when an engine on our own earth. We see now one pole leaves a trail of condensed steam behind now another bowed toward us, and his it; or rather it may be compared to what equatorial zone is curved now downward would take place if a steam-engine were now upward, so as to form two half ovals, moving in the same direction as the wind (at these opposite seasons,) which, taken but less swiftly, so that steam-clouds would together, would make an ellipse about be carried in front instead of behind.
Now, heat is the only form of force if he reflected the whole of the light fallwhich could account for the formation of ing upon him! According to the latter, the enormous masses of cloud suspended and more trustworthy series, Jupiter does in the atmosphere of Jupiter. And it not indeed shine quite so brightly as Proseems difficult to conceive that the clouds fessor Bond supposed, but the planet yet could be maintained at a great height shines three times as brightly as a globe of above the real surface of the planet unless equal size would shine, if similarly placed, that surface were intensely hot,-as hot but constituted like Mars, and four times as perhaps as red-hot iron. If we supposed brightly as such a globe would shine if this to be the case we should find at once constituted like our moon. Jupiter shines an explanation of the ruddy aspect of the in fact very nearly as brightly as though he dark belts. Nor would the change of the were constituted like one of our terrestrial great equatorial belt from white to red im- clouds! ply more than that, owing to some un- This result is highly significant. If Juknown cause, clouds had not formed du- piter showed no belts and shone with a ring the last two years over the planet's pure white color, we could explain it at equatorial zone, or, having formed, had once by simply regarding Jupiter as wholly been dispersed in some way. We need cloud-covered or snow-covered (for snow not even imagine a complete dispersion, and cloud shine with nearly equal lustre since the best telescopes
, and notably Mr. when similarly illuminated.) But the great Buckingham's fine 21-inch refractor, have dark belts which occupy so large a portion shown always a multitude of minute cloud- of the planet's disk altogether negative like objects over the ruddy equatorial zone. this supposition. We seem compelled to
But the idea of a red-hot planet, or of believe that some considerable portion of a planet partially red-hot, will appear at a the planet's lustre is inherent. first view too bizarre to be entertained even Let us, however, proceed carefully here. for a moment. We have been so accus- We have to inquire first how far Zöllner's tomed to regard Jupiter and Saturn as oth- results can be trusted, and secondly, whether worlds, that the mind is disposed to re-er they are corroborated by any independject the conception that they can be so in- ent evidence. Now Zöllner carefully estitensely heated as to be utterly unfit to be mated the weight of his observations, we the abode of living creatures.
may say he jealously estimated their weight, This unwillingness to accept startling for it must be remembered that he was in ideas is not to be altogether reprehended, no way interested in securing a greater or since it prevents the mind from forming less result
, while he was greatly interested rash and baseless speculations. Yet we in so stating the value of his results that must not suffer this mental habitude, excel- those who might succeed him in the inlent though it may be in its proper place, quiry should not detect any serious error to interfere with the admission of conclu- in his estimate. But his opinion of the sions which seem based on trustworthy evi- probable degree of error in his observadence. Let us then inquire whether the tions was such as scarcely to affect to an startling hypothesis to which we have been appreciable extent the statements we have led by the study of observed facts may not made above. Taking Zöllner's lowest esbe found to be in agreement with other timate of Jupiter's brightness, that state. facts not yet considered.
ment remains appreciably correct. It will be obvious that if the real globe And next as to corroborative evidence. of Jupiter is thus intensely heated, a por- It happens that we have a very delicate tion of the planet's light must be inherent. means of measuring the degree of Jupiter's Therefore we might expect that the planet luminosity, as compared with that of other would shine somewhat more brightly than orbs similarly placed. For his satellites a globe of equal size and similarly placed, pass across his face, and nothing can be shining merely by reflecting the sun's light. easier than to observe whether they appear Now two series of good observations have darker or brighter than his surface. been made upon the luminosity of Jupiter. It was an observation such as this which One was made by the late Professor Bond, Mr. Lassell had made on the night when of America, the other by Dr. Zöllner, of he noticed the ruddiness of Jupiter's great Germany. According to the former, Ju- medial belt. By a singular chance Father piter shines more brightly than he would Secchi made a similar observation during
New SERIES.-VOL. XVI., No. 1.
his researches, and the reader will see, Although a part of the difference dwelt when we have quoted the narratives of on in Secchi's closing words may be asboth these observers, that the comparative cribed to the oblique incidence of the light darkness of all four satellites will have been near the planet's edge, yet it does not apestablished. “The fourth satellite,” says pear to us that the whole difference can Lassell, “ has begun again for a season to be thus explained. A difference so great cross the planet's disk, and I have looked that a satellite appears as a bright point out for opportunities of observing its pas- close by the planet's edge, and almost sages, and was favored on the night of the black near the middle of the disk, suggests 30th December last by witnessing a part that the light near the edge is not reinof its passage under circumstances more forced by the inherent luminosity of our than usually propitious. On its first en- theory, that luminosity adding only to the trance it was scarcely to be distinguished brightness of the central parts of the disk. from the edge, not appearing at all as the We would not insist too strongly on this others do, as a round bright spot. As it inference, because the darkening due to advanced it grew gradually manifestly dark- oblique incidence is, under certain circumer than the surface of the planet, and by stances, very obvious to direct observathe time it had advanced a fourth of the tion. But it seems to us that a portion way across it had become a very dark if of the difference should be referred to the not a black spot-o dark, indeed, that if inherent luminosity of the central parts of I had looked at Jupiter without knowing the disk. This being admitted, it would any thing of the positions of his satellites, follow that the real solid globe of the I should have said that a shadow (of a planet is much smaller than the globe satellite) was passing. I remember having measured by astronomers; and that, thereseen the like phenomenon many years fore, instead of that amazingly small denago; but my impression is that I had nev- sity which is so perplexing a feature of the er seen the disk of the satellite so near to planet's physical condition, Jupiter's globe absolute blackness before. Of course it is may have a density equaling or exceedonly by contrast that it can possibly so ap- ing that of the earth. . pear; and we have in this fact a striking And after all, let us remember that the proof of the exceeding brilliancy of the theory that Jupiter is an intensely heated surface of the planet. In the same way globe-a theory to which we have been the solarspots, if not surrounded by the mar- led by the consideration of many observed velous splendor of the sun's surface, would facts, and which in its turn suggests very doubtless appear as brilliant objects.” satisfactory explanations of other observed
Next let us hear Secchi's account. “On facts—would merely show that, as Jupiter the evening of February 3d,” he says, “I and Saturn hold an intermediate position observed the transit of the third satellite between the sun and the minor planets in and that of its shadow. The satellite respect of size, so those giant orbs hold a seemed almost black when it was upon corresponding position in respect of inthe middle of the planet's disk, and nota- herent heat. Roughly speaking, the earth bly smaller than its shadow, which was is 8000 miles, the sun 840,000 miles, visible at the same time; one would have in diameter, and Jupiter, with his diamRestimated it at only one-half. In ap- eter of 82,000 miles, comes midway proaching the edge the satellite disap- between these orbs. Now, the sun is peared, and reappeared soon after, close at a white heat, and the earth gives out by the edge, but as a bright point. This only what is called obscure heat; and if fact is not a new one for the other satel- Jupiter's globe is at a red heat, he again lites, but for the third it is unique. This comes midway between the sun and the result shows also the great difference of earth. luminosity at the centre and near the edge We should be led by the theory here of the planet, a difference already con- maintained to regard the major planets firmed by photography."
which travel outside the zone of asteroids It is hardly necessary to point out how as in a sense secondary suns. So viewed, strikingly these facts illustrate and confirm they could not be regarded as orbs fit for Dr. Zöllner's observations. But they also the support of living creatures. Yet, as supply fresh evidence of a very interesting each of them is the centre of a scheme of nature.
dependent worlds, of dimensions large