STARRY WONDERLAND

Taranaki Daily News, 3 August 1935, Page 1 (Supplement)

STARRY WONDERLAND

SEEN FROM THE ROCKET

B. Dudley,

(By the Rev.

FR.A.S.)

(Written for Young Folic.)

Continuing our amazing journey with Jeans in his rocket, let us listen attentively while he describes what the scenery would be like on worlds circling round the star Sirius, which is a big white-hot sun. “If Sirius had planets,” he states, “the eyes of their inhabitants would probably have adjusted themselves to ultra-violet colours, for which we have no names because we cannot see them.” To such inhabitants life would be very different from ours. Glass, for instance, would not let the ultra-violet rays pass through, so that the Sirians could not use it for their windows. On the other hand, they could employ it very well for the walls of their houses, only remembering the proverb that they who live in glass houses must not be first to throw stones. If the Sirians had an atmosphere like ours to live in, then their sky would look always perfectly black, because air is unable to let the Sirian light through, if it contains as much ozone as our atmosphere. We are next taken to have a peep at certain stars which are both very small and very heavy. The average ton of matter in our sun, as all astronomers know, occupies- about a cubic yard. But the average ton of matter in some of these dwarfish stars “would all go,” he tells us, “inside a thimble.” The big star mentioned last week, Omicron Ceti, on the other hand, “requires, to accommodate a ton, as much space as the interior of Waterloo station.” There is no railway station in New Zealand equal in'size to that at Waterloo, London. The most massive star known to astronomers is one called Plaskett’s star. This is a double—the two stars being locked together and moving about one another perpetually, each of them being about a hundred times the weight of the sun. We are also shown a remarkable star in the constellation Orion, the Hunter. . This star, known as Rigel, is of special interest because it is one of the most luminous known. It burns with a glare about 15,000 times that of the sun. In his book “Through. Space and Time,” Sir James gives us five photographs of the same part of the sky. This Is in the constellation Auriga. In one of the pictures is seen a single faint star. So feeble is it that it is utterly impossible for the naked eye to see it. The next shows the same region as seen in the big telescope at Mount Wilson, California. Here come into view about 30 others. The eyepiece of the instrument is again, changed, and there now appear on the photographic plate scores of others; while the solitary 9th magnitude star seen in the first picture is too powerful for the plate and comes out on it as a big white and blurred image. Again, in picture four, with increased telescopic power, scores of stars become hundreds. In picture five there are seen many hundreds. Thus we discover what the telescope and the camera can do in assisting the eye as we look out towards the starry wonderlands around us.

Let us not imagine that the stars are moving hither and thither at random, as if there were no method or order in the skies. It has lately been shown that the whole system of stars is rotating round a centre, “much as a cart-wheel rotates about its. hub,” Jeans says. “This rotation,” he also informs us, “whirls the sun through space at a rate of about 290 miles a second, yet the wheel is so vast that the ; sun must travel at this speed for about 250 million years before it has made one complete circle round the hub.” This rotating cart-wheel is compared by our author to the hour hand of a clock which turns completely round once in 12 hours. “If we now slow down the hour hand,” writes Jeans, “until it turns at the same rate as the system of stars, the jump which at present occurs every second would take more than 5000 years—almost the whole of human civilisation.” Yet a study of the ages of the stars seems to show that our wheel must have made thousands, and perhaps hundreds of thousands of complete revolutions. And of course, since we belong to the sun, the earth being a member of the solar system, we go where he goes—one turn in 260 million years. When Jeans speaks of the hub, he does not want us to think of our system of stars as revolving round some bright centre or some supermighty star. The actual centre could be an empty part of space. Astronomers are still uncertain of the exact location of this centre. It is at present thought to be somewhere between the constellations Sagittarius and Ophiuchus. Now, the sun, and of course the entire solar system with its nine planets, including the teeming millions of people who live upon the earth, would “fly off the whirling wheel into space like a speck of mud off a bicycle wheel, were it not that the gravitational pull of the other stars restrains it.” This gravitational pull keeps the sun moving in an orbit, just as the gravitational pull of the sun keeps the earth in its place; at its proper distance, that is to say. Jeans estimates that the total number of stars in the Great System is certainly more than a hundred thousand million; and he thinks it would come near the truth if this number were doubled. In this estimate he takes no notice of the millions of other cart-wheels which may in some cases have a like number of stars within them. Of this vast multitude our naked sight can - detect only about 5000, half that number in the southern hemisphere and half in the northern.

You may like to know what our author has to say about the size of this cartwheel as he calls it. Let me explain first that the somewhat irregular belt of stars which crosses the heavens from side to side and is so easily seen on a clear, moonless night, forms a complete ring, the unseen half of it lying beneath our feet and crossing the skies over the heads of people who live in the northern hemisphere. This ring marks the boundary of our system of stars—the rotating cart-wheel. The “Milky Way,” as this ring is called, looks milky merely because it consists of millions of stars so far away that we cannot see them as individuals. We see them only in a mass. It is this ring, then, about whose size we are inquiring. The answer given by Sir James Jeans is that it has a diameter of 200,000 light years. In other words, a ray of light travelling at the speed of 670 million miles an hour would take 200,000 years to cross the ring!