Urania Part 13

"Terrestrial humanity is young," answered Spero. "You must not despair.

It is a child, and still in primitive ignorance. It is amused at trifles, and obeys masters of its own giving. You like to divide yourselves into nations, to trick yourselves out in national costumes, and to exterminate each other to music! Then you raise statues to those who have led you to butchery. You ruin yourselves, you commit suicide, and yet you cannot live without wresting your daily bread from the Earth. That is a sad condition of things, but one which fully satisfies the greater part of the dwellers on your planet. If some of them, with higher aspirations, think occasionally of problems of the higher order, of the nature of the soul or the existence of G.o.d, the result has been no better, because they have put their souls outside of Nature, and have invented strange, horrible G.o.ds, who never existed except in their perverted imaginations, and in whose name they have committed all kinds of outrages against the human conscience, have blessed all crimes, and bound weak minds in a slavery from which it will be difficult for them to escape. The lowest animal on Mars is better, finer, gentler, more intelligent, and greater than the G.o.d of the armies of David, Constantine, Charlemagne, and all your crowned a.s.sa.s.sins. There is therefore nothing surprising in the coa.r.s.eness and stupidity of terrestrial humanity. But the law of progress governs the world. You are more advanced than at the period of your ancestors of the stone age, whose wretched existence was spent in fighting night and day with ferocious beasts. In a few thousands of years you will be more advanced than you are now. Then Urania will reign in your hearts."

"It would require a brutal material fact to teach and convince human beings. If, for instance, we could some day enter into communication with the neighboring world which you inhabit, not into physical communication with one isolated person of it, as I am now doing, but with the planet itself, by hundreds and thousands of witnesses, that would be a gigantic stride towards progress."

"You could do it now if you chose, for we Martials are all prepared for it, and have even tried it many times. But you have never replied to us.

Solar reflections, showing geometrical figures on our vast plains, prove to you that we exist. You could reply to us by like figures also displayed on your plains, either during the day by the sun, or during the night by the electric light. But you never even think of it; and if some one should propose to try it, your courts would interpose to prevent it, for the very idea is immeasurably too high for the general approval of the denizens of your planet. What do your scientific a.s.semblies work for? The preservation of the past. To what do your political a.s.semblies direct their attention? Increasing the taxes. In the land of the blind, one-eyed men are kings.

"But you must not utterly despair. Progress bears you on in spite of yourselves. One of these days, too, you will realize that you are citizens of the sky; then you will live in the light, in knowledge, in the mind's true world."

While the inhabitant of Mars was teaching me the princ.i.p.al characteristics of his new country, the terrestrial globe had turned towards the east, the horizon had sunk lower, and the Moon had gradually risen in the sky, which she was illuminating with her radiance.

Suddenly chancing to lower my eyes to where Spero sat, I could not repress a start of surprise. The moonlight was streaming over him as it did over me, and yet, although my body cast a shadow on the parapet, his figure was shadowless. I arose abruptly to a.s.sure myself of this fact. I turned about at once and stretched out my hand to touch his shoulder, watching the shadow of my gesture on the parapet. But my visitor had instantly disappeared. I was absolutely alone on the silent tower. My very dark shadow was thrown out sharply on the parapet. The Moon was brilliant, the village was sleeping at my feet. The air was mild and very still. And yet I thought I heard footsteps. I listened, and indeed did hear rather heavy footsteps coming towards me. Some one was evidently climbing the tower-stairs.

"Monsieur has not gone down yet?" said the custodian, coming up to the top. "I was waiting to lock the doors, and thought the experiments must be over."

[Ill.u.s.tration]

[Ill.u.s.tration]

IV.

THE FIXED POINT IN THE UNIVERSE.

The memory of Urania and the celestial journey on which she had borne me away, the truths she had made me realize, Spero's history, his trials in his pursuit of the absolute, his apparition, his story of another world, still haunted me, and kept the same problems (partly solved, partly veiled in the uncertainty of our knowledge) incessantly before my mind.

I felt that I had gradually risen to a perception of the truth, and that the visible universe was really but an appearance, which we must pa.s.s through in order to reach reality.

The testimony of our senses is but an illusion. The Earth is not what it seems to be. Nature is not what we think. In the physical universe itself, where is the fixed point upon which material creation is in equilibrium?

The natural and direct impression given by the observation of Nature is that we inhabit a solid, stable Earth, fixed in the centre of the universe. It took long centuries of study and a great deal of boldness to free ourselves from that natural conviction, and to realize that the world we are on is isolated in s.p.a.ce, without any support whatever, in rapid motion on itself and around the Sun. But to the ages before scientific a.n.a.lysis, to primitive peoples, and even to-day to three quarters of the human race, our feet are resting on a solid Earth which is fixed at the base of the universe, and whose foundations are supposed to extend into the depths of the infinite.

And yet from the time when it was first realized that it is the same Sun which rises and sets every day; that it is the same Moon, the same stars, the same constellations which revolve about us, those very facts forced one to admit with absolute certainty that there must be empty s.p.a.ce underneath the Earth, to let the stars of the firmament pa.s.s from their setting to their rising. This first recognition was a turning-point. The admission of the Earth's isolation in s.p.a.ce was astronomy's first triumph. It was the first step, and indeed the most difficult one. Think of it! To give up the foundations of the Earth!

Such an idea would never have sprung from any brain without the study of the stars, or indeed without the transparency of the atmosphere. Under a perpetually cloudy sky, human thoughts would have remained fixed on terrestrial ground like the oyster to the rock.

The Earth once isolated in s.p.a.ce, the first step was taken. Before this revolution, whose philosophical bearing equals its scientific value, all manner of shapes had been imagined for our sublunary dwelling-place. In the first place, the Earth was thought to be an island emerging from a boundless ocean, the island having infinite roots. Then the Earth, with its seas, was supposed to be a flat, circular disk, all around which rested the vault of the firmament. Later, cubic, cylindrical, polyhedric forms, etc., were imagined. But still the progress of navigation tended to reveal its spherical nature, and when its isolation, with its incontestable proofs, was recognized, this sphericity was admitted as a natural corollary of that isolation and of the circular motion of the celestial spheres around the supposed central globe.

The terrestrial globe being from that time recognized as isolated, to move it was no longer difficult. Formerly, when the sky was looked upon as a dome crowning the ma.s.sive and unlimited Earth, the very idea of supposing it to be in motion would have been not only absurd but untenable. But from the time that we could see it in our minds, placed like a globe in the centre of celestial motion, the idea of imagining that perhaps this globe could revolve on itself, so as to avoid obliging the whole sky and the immense universe to perform this daily task, might come naturally into a thinker's mind; and indeed we see the hypothesis of the daily rotation of the terrestrial sphere coming to light in ancient civilizations, among the Greeks, the Egyptians, the Indians, etc. It is sufficient to read a few chapters of Ptolemy, Plutarch, or Surya-Siddhanta for an account of these conjectures. But this new hypothesis, although it had been prepared for by the first one, was none the less bold, and contrary to the feelings inspired by the direct contemplation of Nature. Thoughtful mankind was obliged to wait until the sixteenth century, or, to speak more correctly, until the seventeenth century, to learn our planet's true position in the universe, and to _know_ by supported proofs that it has a double movement,--daily about itself, and yearly about the Sun. From that time only, from the time of Copernicus, Galileo, Kepler, and Newton, has real astronomy existed.

And yet again, that was but a beginning, for the great remodeller of the world's system, Copernicus himself, had no suspicion of the Earth's other motions, or of the distances of the stars. It is only in our own century that the first measurements of the distances of the stars could be made, and it is only in our day that sidereal discoveries have afforded us the necessary data by which we might endeavor to account for the forces which maintain the equilibrium of creation.

The ancient idea of endless roots attributed to the Earth, evidently left much to be desired to minds anxious to go to the bottom of things.

It is absolutely impossible for us to conceive of a material pillar, as thick and as wide as you like (of the diameter of the Earth, for example), sinking down into the infinite; just as one cannot admit the real existence of a stick which should have but one end. No matter how far our mind goes down towards the base of such a material pillar, there is a point where it can see the end of it. The difficulty had been obviated by materializing the celestial sphere and putting the Earth inside it, occupying all its lower portion. But in the first place it became difficult to adjust the motion of the stars, and on the other hand this material universe itself, enclosed in an immense crystal globe, was held up by nothing, since the infinite must extend all around, beneath it, as well as above. Investigating minds were at first obliged to free themselves from the vulgar idea of weight.

Isolated in s.p.a.ce like a child's balloon floating in the air, and more absolutely too, for the balloon is carried by aerial waves, while worlds gravitate in the void, the Earth is a toy for the invisible cosmic forces which it obeys,--a real soap-bubble, sensitive to the faintest breath. Besides, we can easily judge of it by looking at the same time at the whole of the _eleven_ princ.i.p.al motions of the Earth, by which it is moved. Perhaps they will help us to find that "fixed point" which our philosophical ambition asks for.

Thrown around the Sun at a distance of 37,000,000 leagues, and making at this distance its annual revolution around the luminous star, it consequently moves at the rate of 643,000 leagues per day; that is, 26,800 leagues an hour, or 29,450 metres per second. This speed is eleven hundred times more rapid than an express train going at the rate of a hundred kilometres an hour. It is a ball, going with a rapidity seventy-five times greater than that of a bomb, always hurrying on, but never reaching its goal. In 365 days, 6 hours, 9 minutes, and 10 seconds, the terrestrial projectile has returned to the same point of its...o...b..t relative to the Sun, and continues its flight. The Sun, on its part, is moving in s.p.a.ce, following a line oblique to the plane of the Earth's annual motion,--a line drawn towards the constellation of Hercules. The result is, that instead of describing an exact circle, the Earth describes a spiral, and has never pa.s.sed over the same road twice in its existence. To its motion of annual revolution around the Sun there is added perpetually, as a second motion, that of the Sun itself, which draws it, with all the solar system, into an oblique descent towards the constellation of Hercules.

During all this time our little globe pirouettes around itself every twenty-four hours, and gives us the daily succession of days and nights,--diurnal rotation: third motion.

It does not turn upright upon itself, like a top, which would be vertical on a table, but is inclined, as everybody knows, by 23 27'.

This inclination, too, is not always the same; it varies from year to year, from age to age, oscillating slowly by secular periods. That is a fourth kind of motion.

The orbit in which our planet yearly travels around the Sun is not circular, but elliptical. This ellipse itself also varies from year to year, and from century to century; sometimes it approaches the circ.u.mference of a circle, sometimes it lengthens out to a great eccentricity. It is like an elastic ring, which can be bent more or less out of shape. Fifth complication in the Earth's motion.

This ellipse itself is not fixed in s.p.a.ce, but revolves in its own plane in a period of 21,000 years. The perihelion, which at the beginning of our era was at 65 degrees of longitude, starting from the vernal equinox, is now at 101 degrees. This secular displacement of the line of the apsides brings a sixth complication to the motion of our abiding-place.

Here is a seventh. We said just now that our globe's axis of rotation is inclined, and everybody knows that the imaginary prolongation of this axis points towards the polar star. This axis itself is not fixed. It revolves in 25,765 years, keeping its inclination of 22 to 24 degrees, so that its prolongation describes a circle of 44 to 48 degrees in diameter--according to the epoch--on the celestial sphere around the pole of the ecliptic. It is in consequence of this displacement of the pole that Vega, in twelve thousand years, will again become the polar star, as she was fourteen thousand years ago. Seventh kind of movement.

An eighth motion, due to the action of the Moon on the equatorial swelling of the Earth, that of nutation, causes the pole of the equator to describe a small ellipse in eighteen years and eight months.

A ninth, due also to the attraction of our satellite, incessantly changes the position of the globe's centre of gravity and the Earth's place in s.p.a.ce. When the Moon is in front of us, she accelerates the speed of the globe; when she is behind, she r.e.t.a.r.ds us, on the contrary, like a check-rein,--a monthly complication which is added to all the others.

When the Earth pa.s.ses between the Sun and Jupiter, the attraction of the latter, in spite of its distance of 155,000,000 leagues, makes it deviate by 2 m. 10 sec. from its absolute orbit. The attraction of Venus makes it deviate 1 m. 25 sec. the other way. Saturn and Mars also act upon it, but more feebly. These are exterior disturbances, which make up a tenth kind of correction to add to the motion of our celestial barque.

The whole of the planets weigh about one seven hundredth part of the weight of the Sun; the centre of gravity around which the Earth annually turns is not in the very centre of the Sun, but far from the centre, and often even outside of the solar globe. Now, absolutely speaking, the Earth does not turn around the Sun; but the two heavenly bodies, Sun and Earth, turn about their common centre of gravity. Thus the centre of our planet's annual motion is constantly changing place, and we may add this eleventh complication to the others. We might even add many others to these; but the preceding ones are enough to make the degree of lightness and delicacy of our floating island appreciated, subject, as we have seen, to all the fluctuations of celestial influences.

Mathematical a.n.a.lysis goes very far beyond this summary statement. It has found that the Moon alone, which seems to turn so peacefully about us, has more than sixty distinct motions.

The expression is therefore not exaggerated: our planet is but the plaything of the cosmic forces which accompany it in the meadows of the sky, and it is the same with everything existing in the universe. Matter is meekly obedient to force.

Where, then, is the fixed point which we desire for our support?

Our planet, then, formerly supposed to be at the base of the universe, is in fact kept up at a distance by the Sun, which makes the Earth gravitate about it with a speed corresponding to that distance. This speed, caused by the solar ma.s.s itself, keeps our planet at the same mean distance from the central star. A lesser speed would make the weight predominate, and would lead to the Earth's falling into the Sun; a greater speed, on the contrary, would progressively and infinitely send our planet away from its life-giving focus. But at the speed resulting from gravitation, our wandering home remains suspended in permanent stability, just as the Moon is upheld in s.p.a.ce by the force of the Earth's gravity, which makes it circulate about the Earth with the speed requisite to maintain it constantly at the same mean distance. The Earth and the Moon thus form a planetary couple in s.p.a.ce which sustain each other in perpetual equilibrium under the supreme domination of solar attraction. If the Earth existed alone in the universe, it would be forever motionless in the void, wherever it had been placed, with no power to descend or rise or change its position in any way whatsoever; these very expressions--to rise, descend, left or right--having no absolute sense whatever. If this same Earth, while existing alone, had received any impetus whatever, had been thrown with any speed in any direction, it would have whirled away forever in a straight line in that direction, never being able to stop or to slacken its pace or change its motion. It would have been the same thing if the Moon had existed alone with it; they would both have turned about their common centre of gravity, fulfilling their destiny in the same place in s.p.a.ce, flying together, following the direction in which they had been thrown. The Sun existing and being the centre of its system, the Earth, all the planets and their satellites, are dependent upon it, and to it their destiny is irrevocably bound.

Is the fixed point that we are seeking, the solid base which we seem to need to insure the stability of the universe, to be found in that colossal and heavy globe, the Sun?

a.s.suredly not, since the Sun itself is not in repose, for it is bearing us and all its system away towards the constellation of Hercules.

Does our Sun gravitate around an immense sun whose attraction extends to it and controls its destinies as it controls that of the planets? Do investigations in sidereal astronomy lead us to believe that a star of such magnitude can exist in a direction situated at right angles with our course towards Hercules? No; our Sun is influenced by sidereal attraction, but no one star appears to overpower all the others and reign sovereign over our central star.

Although it may be perfectly admissible, or rather certain, that the sun nearest to ours, the star Alpha Centauri, and our own Sun feel their mutual attraction; although this star may be situated at about 90 degrees from our tangent towards Hercules, and, more than that, in the plane of the princ.i.p.al stars, pa.s.sing by Perseus, Capella, Vega, Aldebaran, and the Southern Cross; and although the proper motion of this neighboring sun may be turned sensibly in the opposite direction from ours,--yet we could not consider these two systems as forming one couple a.n.a.logous to that of the double stars; in the first place, because all the known double-star systems are composed of stars much nearer to each other, and then because in the immensity of the orbit described, according to this hypothesis, the attraction of the neighboring stars could not be considered as remaining without influence; and lastly, because the actual rates of speed with which these two suns are moved are much less great than those which would result from their mutual attraction.

The little constellation of Perseus, especially, might very well exert a more powerful action than that of the Pleiades, or than any other group of stars, and be the fixed point, the centre of gravity, of the motions of our Sun, of Alpha Centauri, and the neighboring stars, inasmuch as the cl.u.s.ter of Perseus is not only at right angles with the tangent of our movement towards Hercules, but also in the great circle of the princ.i.p.al stars and precisely at the intersection of this circle with the Milky Way. But here another factor comes in, of more importance than all the preceding ones,--this Milky Way, with its eighteen millions of suns, of which it would a.s.suredly be audacious to seek the centre of gravity.

But what is the whole entire Milky Way, after all, compared with the milliards of stars which our mind contemplates in the bosom of the sidereal universe? Is not this Milky Way itself moving like an archipelago of floating islands? Is not every resolvable nebula, each cl.u.s.ter of stars, a Milky Way in motion under the action of the gravitation of other universes, which call to it and appeal to it through the infinite night?

Our thoughts are transported from star to star, from system to system, from region to region, in the presence of unfathomable grandeurs, in sight of celestial motions whose speed we are but just beginning properly to value, but which already surpa.s.ses all conception. The proper annual motion of the sun Alpha Centauri exceeds 188 millions of leagues per year. The proper motion of the 61st of Cygnus (second sun in the order of distances) is equivalent to 370 millions of leagues per year, or about one million of leagues per day. The star Alpha Cygni comes to us in a direct line at a speed of 500 millions of leagues per year. The proper motion of the star 1830 of Groombridge's Catalogue rises to 2,590 millions of leagues per year, which represents seven millions of leagues per day, 115,000 kilometres per hour, or 320,000 metres per second! These are minimum estimates, inasmuch as we certainly do not see perpendicularly, but obliquely, the stellar displacements thus measured.

What projectiles! They are suns thousands and millions of times heavier than the Earth, launched through the unfathomable void with giddy rates of speed, revolving in immensity under the influence of the gravitation of all the stars of the universe. And these millions and thousand millions of suns, planets, cl.u.s.ters of stars, nebulae, worlds in their infancy, worlds near their end, rush with equal velocity towards goals of which they are ignorant, with an energy and intensity of action before which gunpowder and dynamite are like the breath of sleeping babes.

And thus everything hurries on through all eternity perhaps, without being able ever to reach the unexisting limits of infinity.... Motion, activity, light, life everywhere. Happily so, without doubt. If all these innumerable suns, planets, earths, moons, comets, were fixed and immovable, petrified kings in their eternal tombs, how much more formidable, but also more mournful, would be the aspect of such a universe! Can you imagine the whole creation stopped, benumbed, mummified? Is not such an idea unbearable? Is there not something funereal about it?

What causes these motions? What maintains them? What regulates them?

Universal gravitation, invisible force, which the visible universe (what we call matter) obeys. A body attracted from infinity by the Earth would attain a velocity of 11,300 metres per second; just as a body thrown from the Earth with that speed would never fall again. A body attracted by the Sun from the infinite would attain a speed of 608,000 metres; and a body thrown by the Sun with that swiftness would never return to its point of departure. Cl.u.s.ters of stars may give us velocities much more remarkable still, but which are explained by the theory of gravitation.

A glance at a map of the proper motions of the stars is enough to make one understand the variety and grandeur of these motions.