Astronomy for Amateurs - Camille Flammarion (ebook reader with android os TXT) 📗

infinite, and "positive" science, founded upon our senses only, is altogether inadequate, although it is the only possible basis of our reasoning. We must learn to see with the eyes of our spirit.

As to the planetary systems other than our own, we are no longer reduced to hypotheses. We already know with certainty that our Sun is no exception, as was suggested, and is still maintained, by some theorists. The discovery in itself is curious enough.

It is surely an exceptional situation that, given a sidereal system composed of a central sun, and of one or more stars gravitating round him, the plane of such a system should fall just within our line of vision, and that it should revolve in such a way that the globes of which it is composed pass exactly between this sun and ourselves in turning round him, eclipsing him more or less during this transit. As, on the other hand, the eclipses would be our only means of determining the existence of these unknown planets (save indeed from perturbation, as in the case of Sirius and Procyon), it might have seemed quixotic to hope for like conditions in order to discover solar systems other than our own. But these exceptional circumstances have reproduced themselves at different parts of the Heavens.

Thus, for instance, we have seen that the variable star Algol owes its variations in brilliancy, which reduce it from second to fourth magnitude every sixty-nine hours, to the interposition of a body between itself and the Earth, and celestial mechanics has already been able to determine accurately the orbit of this body, its dimensions and its mass, and even the flattening of the sun Algol. Here, then, is a system in which we know the sun and an enormous planet, whose revolution is effected in sixty-nine hours with extreme rapidity, as measured by the spectroscope.

The star δ of Cepheus is in the same case: it is an orb eclipsed in a period of 129 hours, and its eclipsing planet also revolves in the plane of our vision. The variable star in Ophiuchus has an analogous system, and observation has already revealed a great number of others.

Since, then, a certain number of solar systems differing from our own have been revealed, as it were in section, to terrestrial observation, this affords us sufficient evidence of the existence of an innumerable quantity of solar systems scattered through the immensities of space, and we are no longer reduced to conjecture.

On the other hand, analysis of the motions of several stars, such as Sirius, Procyon, Altaïr, proves that these distant orbs have companions,—planets not yet discovered by the telescope, and that perhaps never will be discovered, because they are obscure, and lost in the radiation of the star.

Some savants have asserted that Life can not germinate if the conditions of the environment differ too much from terrestrial conditions.

This hypothesis is purely gratuitous, and we will now discuss it.

In order to examine what is happening on the Earth, let us mount the ladder of time for a moment, to follow the evolutions of Nature.

There was an epoch when the Earth did not exist. Our planet, the future world of our habitation, slept in the bosom of the solar nebula.

At last it came to birth, this cherished Earth, a gaseous, luminous ball, poor reflection of the King of Orbs, its parent. Millions of years rolled by before the condensation and cooling of this new globe were sufficiently transformed to permit life to manifest itself in its most rudimentary aspects.

The first organic forms of the protoplasm, the first aggregations of cells, the protozoons, the zoophytes or plant-animals, the gelatinous mussels of the still warm seas, were succeeded by the fishes, then by the reptiles, the birds, the mammals, and lastly man, who at present occupies the top of the genealogical tree, and crowns the animal kingdom.

Humanity is comparatively young upon the Earth. We may attribute some thousands of centuries of existence to it ... and some five years of reason!

The terrestrial organisms, from the lowest up to man, are the resultant of the forces in action at the surface of our planet. The earliest seem to have been produced by the combinations of carbon with hydrogen and nitrogen; they were, so to speak, without animation, save for some very rudimentary sensibility; the sponges, corals, polyps, and medusæ, give us a notion of these primitive beings. They were formed in the tepid waters of the primary epoch. As long as there were no continents, no islands emerging from the level of the universal ocean, there were no beings breathing in the air. The first aquatic creatures were succeeded by the amphibia, the reptiles. Later on were developed the mammals and the birds.

What, again, do we not owe to the plant-world of the primary epoch, of the secondary epoch, of the tertiary epoch, which slowly prepared the good nutritious soil of to-day, in which the roses flourish, and the peach and strawberry ripen?

Before it gave birth to a Helen or a Cleopatra, life manifested itself under the roughest forms, and in the most varied conditions. A long-period comet passing in sight of the Earth from time to time would have seen modifications of existence in each of its transits, in accordance with a slow evolution, corresponding to the variation of the conditions of existence, and progressing incessantly, for if Life is the goal of nature, Progress is the supreme law.

The history of our planet is the history of life, with all its metamorphoses. It is the same for all the worlds, with some exceptions of orbs arrested in their development.

The constitution of living beings is in absolute relation with the substances of which they are composed, the environment in which they move, temperature, light, weight, density, the length of day and night, the seasons, etc.—in a word, with all the cosmographic elements of a world.

If, for example, we compare between themselves two worlds such as the Earth and Neptune, utterly different from the point of view of distance from the Sun, we could not for an instant suppose that organic structures could have followed a parallel development on these planets. The average temperature must be much lower on Neptune than on the Earth, and the same holds for intensity of light. The years and seasons there are 165 times longer than with us, the density of matter is three times as weak, and weight is, on the contrary, a little greater. Under conditions so different from our own, the activities of Nature would have to translate themselves under other forms. And doubtless the elementary bodies would not be found there in the same proportions. Consequently we have to conclude that organs and senses would not be the same there as here. The optic nerve, for instance, which has formed and developed here from the rudimentary organ of the trilobite to the marvels of the human eye, must be incomparably more sensitive upon Neptune than in our dazzling solar luminosity, in order to perceive radiations that we do not perceive here. In all probability, it is replaced there by some other organ. The lungs, functioning there in another atmosphere, are different from our own. So, too, for the stomach and digestive organs. Corporeal forms, animal and human, can not resemble those which exist upon the Earth.

Certain savants contend that if the conditions differed too much from terrestrial conditions, life could not be produced there at all. Yet we have no right to limit the powers of Nature to the narrow bounds of our sphere of observation, and to pretend that our planet and our Humanity are the type of all the worlds. That is a hypothesis as ridiculous as it is childish.

Do not let us be "personal," like children, and old people who never see beyond their room. Let us learn to live in the Infinite and the Eternal.

From this larger point of view, the doctrine of the plurality of worlds is the complement and the natural crown of Astronomy. What interests us most in the study of the Universe is surely to know what goes on there.

These considerations show that, in all the ages, what really constitutes a planet is not its skeleton but the life that vibrates upon its surface.

And again, if we analyze things, we see that for the Procession of Nature, life is all, and matter nothing.

What has become of our ancestors, the millions of human beings who preceded us upon this globe? Where are their bodies? What is left of them? Search everywhere. Nothing is left but the molecules of air, water, dust, atoms of hydrogen, nitrogen, oxygen, carbon, etc., which are incorporated in turn in the organism of every living being.

The whole Earth is a vast cemetery, and its finest cities are rooted in the catacombs. But now, in crossing Paris, I passed for at least the thousandth time near the Church of St. Germain-l'Auxerrois, and was obliged to turn out of the direct way, on account of excavations. I looked down, and saw that immediately below the pavement, they had just uncovered some stone coffins still containing the skeletons that had reposed there for ten centuries. From time immemorial the passers-by had trampled them unwittingly under foot. And I reflected that it is much the same in every quarter of Paris. Only yesterday, some Roman tombs and a coin with the effigy of Nero were found in a garden near the Observatory.

And from the most general standpoint of Life, the whole world is in the same case, and even more so, seeing that all that exists, all that lives, is formed of elements that have already been incorporated in other beings, no longer living. The roses that adorn the bosom of the fair ... but I will not enlarge upon this topic.

And you, so strong and virile, of what elements is your splendid body formed? Where have the elements you absorb to-day in respiration and assimilation been drawn from, what lugubrious adventures have they been subject to? Think away from it: do not insist on this point: on no account consider it....

And yet, let us dwell on it, since this reality is the most evident demonstration of the ideal; since what exists is you, is all of us, is Life; and matter is only its substance, like the materials of a house, and even less so, since its particles only pass rapidly through the framework of our bodies. A heap of stones does not make a house. Quintillions of tons of materials would not represent the Earth or any other world.

Yes, what really exists, what constitutes a complete orb, is the city of Life. Let us recognize that the flower of life flourishes on the surface of our planet, embellishing it with its perfume; that it is just this life that we see and admire,—of which we form part,—and which is the raison d'être of things; that matter floats, and crosses, and crosses back again, in the web of living beings,—and the reality, the goal, is not matter—it is the life matter is employed upon.

Yes, matter passes, and being also, after sharing in the concerted symphony of life.

And indeed everything passes rapidly!

What irrepressible grief, what deep melancholy, what ineffaceable regrets we feel, when as age comes on we look back, when we see our friends fallen upon the road one after the other, above all when we visit the beloved scenes of our childhood, those homes of other years, that witnessed our first start in terrestrial existence, our first games, our first affections—those affections of childhood that seemed eternal—when we wander over those fields and valleys and hills, when we see again the landscape whose aspect has hardly changed, and whose