WHAT IS THE UNIVERSE?

Waipa Post, Volume 42, Issue 3304, 2 June 1931, Page 7

WHAT IS THE UNIVERSE?

TO THE SUN BY ROCKET. (By Sir James Jeans.) It is not so long since astronomers thought of the stars merely as bright points of light in the sky. If some looked fainter than others, this might be simply because they were farther away. In any case it was certain that they were all too far away to find out much about them. The giant telescopes of to-day make it possible to study the stars in great detail. They are treated no longer as mere points of light, but as complicated systems to be weighed and measured. The astronomer measures not only their sizes, but also the amount of radiation they pour into space in the form of lighgt and heat and the temperature of the still hotter interior in which the radiation is generated. This intensive study has led to remarkable results. The stars are found to show a variety which can be described only as amazing. They show a range in size which is as great as that between a speck of dust and a house, and as great a range in candle power as that between a glowworm and a searchlight. The range in their weights is less marked; still, it is about equal to that between a feather and a cricket balk

Our sun could hardly. expect to strike the happy mean in every way; yet, as a matter of fact, it never misses it very badly. To put the same thing in another and rather less complicated way, the sun is totally undistinguished in all respects in weight, in size, in heat, and in candle power.

Let us try to understand something of what the stars really are, what they are made of, what makes them shine, why they differ so much one from another, and so on. Before we discuss the more weird varieties of star, let us first discuss that very average ordinary star —our own sun. Even this may appear weird enough before we have finished with it. Let us seal ourselves in a rocket and persuade someone to shoot us toward the sun. We need start only with speed enough to carry us a short distance away from the earth—about seven miles a second will do—and the sun’s gravitational pull will do the rest. It will drag us down into the sun whether we like it or not. If we start at seven miles a second, the whole journey will take about ten weeks.

Even in the first few seconds of our journey we shall notice the sun getting bluer and the sky getting blacker.’ A layer of air makes sunlight look redder than it is. We have a proof of this at sunset. The sunlight comes to us through an unusually thick layer of air, and looks unusually red. As we get outside the earth’s atmosphere we get free from this reddening effect altogether. We begin to see the sun for what it really is—a vivid, bluish globe of light set in a sky as black as that of midnight.

If we are wise we shall have started some time near new moon, because then our path will take us past the moon, and we can study it also. Down behind us the surface of the earth looks dim and blurred; this because we see it through a thick layer of air, clouds, and dust. The face of the moon looks strangely clear by comparison. The reason is that it has no atmosphere, and no rain, fog, clouds, or dust to blur our vision. We see no qities, fields, or forests. We are looking on a dead world. Ninety-five years ago a New York newspaper perpetrated what was later known as the “ great moon hoax.” It published whooly fraudulent articles, which claimed to describe the moon as seen through a giant new telescope in South Africa. The articles described trees of amazing growth, weird animgls, and flying men, all of types utterly different from anything kpown on earth. By these discreditable methods a little-known newspaper increased its sales until it had the largest circulation of any paper in the world—a proof of the interest men feel in the problem of life in other worlds. *

Our telescopes show us a very different picture from that drawn by the American newspaper. The surface of the moon consists largely of• vast flat deserts, showing no signs of cultivation or life of any kind. The surface probably consists of layers of volcanic ash. Scattered over the surface are circular elevations which look like the craters of extinct volcanoes, which is what they probably are. Many of themi are large enough to hold whole English counties. Here and there we see immense jagged peaks and ranges of mountains, as sharp-cut as when they first came into existence. The mountains on our earth have been weathered by millions of years of snow, rain, and wind, but here we can see no trace of weathering.