Martha Evans Martin

“ Then, too, the spring o’ the year is the most likely time to see Mercury in the evening sky. He comes into his best position for this view of him just when the evenings are growing longer and milder and one begins to hunger for outdoor things, so that the quest of him at that time has the gladness that goes with our first excursions into the open after a winter’s housing, whether it be in search of flowers, or birds, or stars, or simply the general loveliness of everything that belongs to the beginning of the outdoor season. ”

“ Together the earth and they circle ceaselessly around and around the sun, following in nicely adjusted orbits that great luminary as it sweeps majestically on through space toward the beautiful Vega, itself a sun, and, so far as we now know, in this close companionship we shall continue until every planet and the sun itself has become cold and dark and lifeless. ”

“ From Mars the earth shows all the phases that Venus shows to us. When Mars is flaming down upon us in his position of greatest brilliancy we present to him a thin crescent. When he sees our full face we are on the opposite side of the sun from him. It would be necessary to have a more brilliant electrical illumination than any we have yet seen to lighten the dark side of the earth and exchange signals with Mars when we are nearest to him—if, indeed, our atmosphere would permit from Mars any view at all of the surface of the earth, which is not at all certain. ”

“ Like individuals of whatever kind, they impress different persons in different ways. As I have watched them from year to year I have come to have a very distinct impression of Jupiter as slow and majestic, and yet not lacking in joviality; Saturn as friendly, but reserved; Mars as sturdily brisk and busy; Venus as always gracious and smiling; and Mercury as irresponsible and roguish. Others might have an entirely different feeling in regard to them; but an intimate acquaintance with them, which is not wholly scientific, cannot fail to stamp them as in some sort individuals. ”

“ But if he does stop to think about it and notices that it is far larger than any star he has noted before, that it hangs low in the western sky early in the evening, and shines with a brilliant silvery light, and if he then learns that it is Venus, will he not always have a pleasant thrill of recognition when he again sees such a star in such a position and knows it as Venus, among the planets as surpassing in beauty as the goddess of that name was among the immortals? ”

“ Yet, being one of the inferior planets, with her orbit smaller and nearer the sun than that of the earth, she can never get so far from the sun as to be at any uncomfortable height for viewing, and hence, when she can be seen at all, is always an obvious bit of brilliancy and a joy to the beholder. She is never higher in the sky than forty-five degrees, which is half-way between the horizon and the zenith, and is never farther away from the sun than forty-eight degrees. One frequently sees a bright planet higher up in the heavens than this; but it is never Venus nor Mercury. ”

“ To know about the planets is to know about ourselves. The earth is one of them. Whatever their origin, the earth’s is the same. It and they are formed from the same nebula, controlled by the same central body, subject to the same laws, and destined for the same fate in the end. In this, the stars and the planets are not alike. They all shine upon us with the same sweet friendliness, and commonly we make no difference between them in our feeling for them. ”

“ In view of the fact that he is the only planet that twinkles, may it not suggest, when we see his ruddy face peering through the thick atmospheric mists near our horizon, that the impish little body is winking at us, and that it may be with planets as it is with people: they may not always be in an unfortunate plight because their fate is different from ours? ”

“ Mercury is the only planet that in color even suggests Mars, and for Mercury it can never be mistaken after one has once seen the two planets. Mercury, we know, is always very near the sun; but when visible at all is, even in that unfavorable situation, always as bright as a first-magnitude star. Mars is near the sun, to our view, only when it is approaching conjunction, and it is then so far from us that it always appears as a rather small star, and, while never insignificant, is, in this situation, quite inconspicuous even as compared with the rarely visible Mercury. ”

“ And when the first frosts began to strip the leaves from the trees we found the compensation that nature always gives when she destroys one beauty: we could see earlier in the evening, through the bare branches, that lovely yellowish disc, with its suggestion of aloofness and grandeur that is peculiar to it. ”

“ In either position it never twinkles as Mercury sometimes does, but shines so steadily and softly that at times its disc can almost be seen with the naked eye, and it has such brilliancy that its light can often be seen in the daytime, if one knows when and how to look for the planet. At its brightest it frequently throws a light sufficiently strong to cast a shadow, as one may easily prove by holding a book or some other opaque object between Venus and a white background, such as the wall of a white house. ”

“ It is a matter for regret that Uranus does not come more easily within our view; for he is a very beautiful planet, pale green in color, and unlike any of the others in his aspect. There are, however, very few persons nowadays who can see him without the aid of at least a small glass, and to most of us he must ever remain a body with which we can have no personal acquaintance. None the less he must have an interest to us such as attaches always to anything so closely related to us, and sharing with us a common origin and a common destiny. ”

“ With them, as with other natural objects, it requires observation truly to know them. But then, observation, when one gets a little started in it, is a great deal more interesting, a great deal more absorbing, than any reading about them can ever be. It is also a very easy thing to begin, for, after all, it is not much more than looking and then looking again. In doing this one can hardly tell just when an object ceases to be strange, and then becomes familiar, and finally is so much a part of every-day knowledge that one knows it at a glance. ”

“ Jupiter does not need the nourishing that the smaller terrestrial planets must have, or die. He is probably almost a sun himself. We are not at all certain that the planet is even so far cooled as to have a solid surface. If it has, there is reason to think that the surface is at least red hot, and gives to the planet a temperature higher than anything we have any comprehension of. Jupiter’s atmosphere, too, is extremely thick and dense, so that the planet is probably so protected that it gets very little heat from the sun and loses very little of its own. ”

“ She seems from her excessive brightness to be covered with clouds; and yet it is manifestly impossible that so small a body could have held an atmosphere throughout these long ages, though clouds presuppose an atmosphere. No doubt, in time this mystery of Vesta’s brilliancy will be made plain. Bright as she is in proportion to her size, and even if she sometimes can be seen, one cannot reasonably expect anything very brilliant to our view from a body not much more than a hundred miles in diameter, shining by reflected light, nearly two hundred million miles away. ”

“ We really know nothing certainly about the rotation of Uranus; but there seems to be some indication that, like Jupiter and Saturn, it revolves swiftly—in perhaps ten or twelve hours, and hence has a very short day and night. The great inclination of its axis must make its seasons so abnormal, from our point of view, that it is difficult to understand what they are. Moreover, the planet is, at this stage of its development, so far from being a habitable body, for beings such as we know anything about, that the subject of its seasons seems not very important or interesting. ”

“ The very name of Venus, for example, and still more the sight of Venus, will call up a conception of Venus, with the particular atmosphere and light and movements and wanderings which make her what she is. On looking at her the observer will at once know why she occupies the special position in the sky in which he sees her, why she is not so bright as she was when she was last in view, or is so much brighter than she was then, about how long she is likely to remain where she is, and when she goes what will become of her. ”

“ It is rather curious to what extent we have a feeling of kinship with Neptune, notwithstanding he dwells forever in far-off space where we cannot expect even to have a glimpse of him without the aid of a telescope. Uranus, the other very distant planet, is so nearly within the limit of ordinary vision that we have always a hope that, by some lucky chance of situation or atmosphere, we may some day be able to see him face to face, and know for ourselves what manner of planet this is which, though a member of our own cosmic family, remains always just beyond easy exchange of glances with us ”

“ So far as light and brilliancy are concerned, it is to Jupiter a very small sun indeed. To an observer on Jupiter the sun would not appear to be more than one-fifth as large as it seems to us. The light it furnishes to Jupiter is twenty-five times less than we receive; and if the planet depended entirely upon the sun for heat, his temperature would be more than two hundred degrees below zero, Fahrenheit. There is every reason to believe that the little heat the sun gives to this mighty planet does not count for much one way or the other at the planet’s present stage of development. ”

“ Whatever each planet affords in the way of life and human interests, all of them must ever be to us the most interesting things in all nature, outside of our own earth, in the two regards already pointed out: first, as the most beautiful objects of vision among all the starry hosts, and, second, as our nearest kindred in this universe of suns and systems of worlds. ”

“ As they wander from constellation to constellation the soft light of their placid faces gives a beauty and variety to the spectacle that endears them to us, and at the same time enhances by contrast their own charm and that of the glittering, unchanging stars.
There is nothing that gives one such a sense of sweet familiarity with the heavens as a really recognizing acquaintance with the planets. They are not, like the stars, associated with particular seasons. ”

“ Mercury, we have every reason to think, cannot support life, mainly because of his lack of atmosphere; but also because of his long rotation, which affords no alternations of day and night, but leaves him with one side always burning-hot and the other inconceivably cold. Venus might very well have a climate not utterly unlike ours, and hence be habitable for beings somewhat resembling us, if she has, as she has long been thought to have, a heavier atmosphere than the earth has, and if she has alternations of day and night. ”

“ The law of gravity, under which the earth draws toward its center every atom of matter surrounding it, and thus holds together all the atoms composing it, is not solely terrestrial in its application. It is probably universal. It certainly applies to every part of our little family of worlds. Every particle in the solar system attracts toward it every other particle in that system with a force determined by its mass and its distance. The sun, by reason of its immense size, compels the earth and all the other planets forever to circle around it. ”

“ For far off and truly mysterious as the planets are, it still is with them as with most other objects in nature: a very little knowledge of their aspects and their ways begets a sense about them that makes the most casual observation of them interesting and, as far as it goes, intelligent. The slightest glance at them betrays some shape, or position, or light, or other quality, which at once makes recognition of them unmistakable. They disclose themselves oftentimes, one can scarcely say how, just as persons with whom we are intimate do by some half-caught outline, motion, or posture ”

“ One may well wonder at the immensity beyond comprehension of the stars, among which our sun is but a very small one, when one considers how even this small one can thus swing huge Jupiter about. For Jupiter is, after the sun itself, the mammoth member of our system. In volume he is larger than all the other planets put together, and in mass he is more than double as large as the combined mass of all the others. He is about equal to the sun in density, and about one-fourth as dense as the earth. ”

“ Unfortunately, our comparative proximity to this beautiful planet does not much aid us in learning anything about her personal peculiarities. Shining only by reflected light, and being, like Mercury, situated nearer to the sun than the earth is, when she comes around to the same side of the sun on which we are, her unillumined side is turned toward us, and at the point of very closest approach she is absolutely invisible to the naked eye. ”

“ These extreme changes of brightness are due not so much to any great distance that Mars goes from us in comparison with other planets as to its coming so very near to us at times. It is, after all, a small body, and no great distance, as heavenly distances go, is required to make it show so. But the eccentricity of its orbit brings it sometimes very near us, and its near approaches are at a time when we can see its entire disc, and not a mere crescent, such as we see when Venus is nearest to us. ”

“ It is worth one’s while, even at some inconvenience, to see Mars at whatever time he is in opposition, for he is a delight to the observer, and always notable in the part of the skies through which he is then passing. There are some aspects of the planet that are so charming at a winter opposition that it is a positive loss not to have seen him at such times. ”

“ It is certain that the planet must be subjected to great extremes of temperature within its range, since its filmy robe of atmosphere cannot protect it to any extent from the direct rays of the sun during the day, nor prevent the heat from escaping with great rapidity at night; so that, whatever heat it may gain in the daytime, it probably loses much of it during the night. Until we know more of the constitution of the atmosphere of Mars we can know nothing certainly about its temperature beyond the fact that it is much colder than ours and more subject to variations. ”

“ It has been suggested that light from the earth is responsible for a dusky illumination of the dark side of Venus, which is occasionally seen, and which enables us to distinguish her entire outline even when only the merest line of a crescent is really illuminated. It is known to be earth-shine that causes what is apparently the same phenomenon often seen by us on the moon; but it seems that there is no reason to think that our earth, at its distance, would be sufficiently brilliant to illuminate Venus even so slightly. ”

“ The sun is a star not very different from most of the other stars, as we believe them to be, except that it is smaller than most of them. It is the center around which we and all the planets revolve, and it is believed that we were all once a part of the very body of it. For astronomers are substantially agreed that the whole solar family, including the sun and all the planets, has been evolved from a great nebula which, in one form or another, at one time filled practically the whole of the immense space from the sun to the outermost planet of the system. ”

“ If Venus is finally proved to have no alternations of day and night, she is still better off than Mercury, who has practically no atmosphere to protect him from the intense heat of the sun. How much protection she has depends altogether on the extent of her atmosphere. It is probably not enough to make the hot side comfortable from our point of view; and Venus, being undoubtedly a solid body with no internal heat, the cold side must be cold beyond anything we have any conception of. ”

“ Once in a while our relative positions are such that we see it pass like a black dot directly over the bright face of the sun. This is called a transit. But a transit does not occur at every inferior conjunction. It would so occur if the planet’s orbit and the earth’s were in exactly the same plane. But the small tilt that they have is sufficient to throw the planet, when it is passing the sun, into such an angle that it does not pass directly between the disc of the sun and us, but a little above or below. ”

“ If there is any one on Venus who is studying the earth, he has a much easier task than we have in our effort to learn something about her. The earth is not only somewhat larger than the planet, but when the two bodies are nearest together the disc of the earth is fully illuminated, and so must show a splendid face; and then, our atmosphere probably interferes less with close observation than that of Venus. ”