The Orbit of the Sun and the Solar System.

Progress, Volume II, Issue 11, 2 September 1907, Page 397

The Orbit of the Sun and the Solar System.

Our sun through the centuries travels a long ellipse, dragging the world , of course, with it, and just within one end of this ellipse blaze the rays of another sun, known to astronomers as the star Arcturus. At the other end of our sun's ellipse are cold voids, vast spaces of absolute zero. Astronomical records are complete enough to show that somewhere more than twenty centuries ago Arcturus was visible only as a luminous speck Now it blares in the evening sk}^, bright as the planet Jupiter, a beacon among the glittering points of fire that stud the firmament this side the Milky Way. Manifestly, our own solar system is approaching the sun Arcturus. The rate of travel of our sun through space, carrying with it its little group of satellites, including the world, has been determined with fair accuracy. We are racing southward through the heavens at the rate of about 5 000 000 miles a year, along an arc whose segment shows undeviating progress in the one direction of Arcturus. Eventually, we will be carried clear around this star and be subjected to its fierce rays ; then we will come back on the other side of the ellipse, and will be carried along a wide and awful sweep towards the star Polaris, now in our rear and to the extreme curve that must be passed before the journey back again begins. How many times our solar system has swung that almost illimitable course, none can ever

following the comet. Clouds and twilight interfered with this photograph. The tail appears to be divided into three branches, with two short streamers near the head.

Fig. 3 is a photograph of the comet's head taken at the same time as No. 2, with the 9in. object glass. The white streaks are star trails with a break caused by clouds. The star near the comet's head is Gamma Geminorum.

Fig. 4 shows the comet taken at the Meanee Observatory on the 15th of August last, with a 3|-in. portrait lens at 45 minutes' exposure. The original negative showed six branches to the tail, but owing to the extreme faintness of two of them, our illustration only depicts four. The length of the tnil in this picture is over 17,000,000 miles. The star with the black dot near the end of the tail is Gamma Geminorum.

4 know or guess. But in this great course there are iust two extremes of season, except that instead of their being six months, they are about 75,000 years apart. The summer season of this vast cycle is unutterable heat— the melting point ; the winter season, frigidity. That we are now a little more than half way down the journey to the summer turning point, and entering upon a springlike opening to a young summer of celestial weather, is made clear by those who study the sky, and to whom the stars present but partial mystery. The astronomer Leroy Tobey has shown that the course we are travelling is regulated by the influence of Arcturus, and that it will carry us around that torrid star in something more than 25,000 years. The turn will bring us so near to it. and into a zone of heat so high, that physical life in its present form will be impossible ; for Arcturus is an incandescent sun. known to be vastly larger than our own. The belief that the world shall die in fire enwrapped a truth — as all beliefs do when they are understood. On the other hand, at the Polaris end of the great ellipse are ' thrilling regions of thick-ribbed ice." Flung to the extreme limit of its course before it turns again in answer to the magnet of its orbit, our sun and the worlds that circle it, being farthest from their source of heat, will dim and fall into a sleep of cold so deep that life will be suspended, to again awaken and again begin ? new development, as the southward turn is made and warmth flows in once more." Elmer E. Towie.