The Ways of the Planets

by Martha Evans Martin

XI

VENUS

Of all the planets lovely Venus is the one that is best known and most admired. It far exceeds all the other planets in brilliancy and beauty when as an evening star it hangs in gracious silvery softness above the sun, which has just passed below the horizon; and it is not less surpassing in loveliness when as a morning star it comes into view shortly before the sun rises, its glowing face still silvery and bright, but yet tinged with the rosy flush of the eastern morning sky.

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 six times as bright as the brightest of all the fixed stars, Sirius, the beautiful dog-star, which we see in winter chasing across the southern skies after Orion.

Venus’s superior brilliancy is due in part to the fact that it comes nearer to the earth than any other planet; but it is also intrinsically brighter than any of the others. From equal areas it reflects almost four times as much light as Mercury and three times as much as Mars.

WHEN AND WHERE TO SEE VENUS

When Venus appears in the sky she is not often mistaken for any other planet. Among all the planets she is the most readily recognized and the easiest to find. This is due largely to her extreme brilliancy and a peculiar silvery appearance that none of the other planets have; but also, in part, to her limited range in the sky, and her favorable situation for observation. Unlike Mercury, she is far enough away from the sun to be seen above the horizon for as much as three hours after sunset, and is then sufficiently high in the heavens to be seen free from the vapors of the atmosphere at the horizon. 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.

We first begin to notice Venus in the evening sky about six weeks after she has passed superior conjunction. She is then very near the sun, and sets a little less than half an hour after sundown. Evening by evening she grows gradually brighter, mounts higher and higher in the sky and, consequently, sets correspondingly later, until in a little more than seven months after superior conjunction, and about six months after we have begun to watch her, she reaches her greatest elongation east from the sun. At that time she is usually somewhere near forty-five degrees above the sun, and is a very lovely and conspicuous object in the evening sky, setting a little more than three hours after sundown.

From this point she begins to travel back toward the sun, still becoming brighter each evening, because she is really coming nearer to us; and in about four or five weeks she attains the greatest brilliancy that she will have as an evening star during the particular revolution she is making. About twelve days after her brightest she will reach the point where she seems to be stationary for a time. This is when she is about to overtake us in our journey around the sun. After a short pause she will move on gradually, her course among the stars then being retrograde or westward; but what we most notice is that she is drawing nearer to the sun, setting earlier each evening, and becoming more and more difficult to see. At the end of about three weeks she is in inferior conjunction, on a line between us and the sun, and invisible. She has run her course as an evening star for nine and a half months, and has been visible anywhere from seven to eight months, the time of her invisibility depending upon the eye of the observer and the conditions of situation and atmosphere.

A week or two later we shall find her a splendid morning star, rising nearly an hour earlier than the sun. About three weeks thereafter she will be at her brightest as a morning star, and will continue to be very brilliant for some weeks. In about five more weeks she will have reached her greatest elongation west of the sun, and will rise about three hours and a half before dawn. Then she will begin to retrace her path, moving eastward, growing smaller all the time as she goes farther away from us, and showing a slower apparent movement, which gives one an agreeable sense of a reluctant parting, until after a little more than seven months she will have reached the sun and will again be in superior conjunction. She has then been a morning star for nine and a half months, and has been visible for about the same length of time that she was when she shone as an evening star.